Commit graph

1122 commits

Author SHA1 Message Date
Linus Torvalds
bba90e0964 Core code updates:
- Reduce the amount of work to release a task stack in context
     switch. There is no real reason to do cgroup accounting and memory
     freeing in this performance sensitive context. Aside of this the
     invoked functions cannot be called from this preemption disabled
     context on PREEMPT_RT enabled kernels. Solve this by moving the
     accounting into do_exit() and delaying the freeing of the stack unless
     the vmap stack can be cached.
 
   - Provide a mechanism to delay raising signals from atomic context on
     PREEMPT_RT enabled kernels as sighand::lock cannot be acquired.  Store
     the information in the task struct and raise it in the exit path.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAmI4U6gTHHRnbHhAbGlu
 dXRyb25peC5kZQAKCRCmGPVMDXSYoSpkEACwgaaQUbqVrpw5yb6LbwzUPnjEdFNN
 uUQCv0XZD8LWbfhcQQVSPWGho7S/w2Mkpdhi0DkVb2K0dkB7EvITSNEC4KoS/yez
 8iQBpv6Lm00quHdNLjkQySSZ4NYB8M1GasBI7zSBjROK/+sRqioTPQsM0oDemGmD
 uMvw0dgDJRlB8X4LZv0xuJbYLdSzu2VOlWd5aJG9BUgHkd7PfUWMlHsa29FP0hkP
 A5yziOnr9kMsmCAsgmiyDW/GmefrEealby5M/jgnxTruF/OLnDsP+PYMlws47fPx
 g6xpHkT5H0zQJ/nMJtK2JAlxpnbIl4cLuUnpn7wX316yjBpP2s3Pw04AVdzPPoBa
 ufAoOLFtnrKN6enIqLWaJHGAsBHEULw6d3/7HoAEQOVWChnQSuWOob8z0QDbvM14
 kKtz+LTrO+P5a15fd4g5+9lFBXJUTnF74SYQNwxIm2cV9hxrf15NhAr8yg+RtUvF
 /ilNNAFtXkASLqs9moEi7U+GyBYwemG+gduVZ3Dw8FBxK/vHmDrhlItcZdKom+UJ
 k4VFDVhzd2GYRHMrcaLfkCYew6ou+LD/rjdPhIU9OQHgILIMLY5aLqxDuyPtHqDz
 TEyF5qsL4wYLIUdsWlqyHISqQQ6LfnpIyko5kb2Zt56sYtrcZr8swDy+yimiEOdL
 G4BzQu0nVbCLhw==
 =uGTc
 -----END PGP SIGNATURE-----

Merge tag 'core-core-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core process handling RT latency updates from Thomas Gleixner:

 - Reduce the amount of work to release a task stack in context switch.
   There is no real reason to do cgroup accounting and memory freeing in
   this performance sensitive context.

   Aside of this the invoked functions cannot be called from this
   preemption disabled context on PREEMPT_RT enabled kernels. Solve this
   by moving the accounting into do_exit() and delaying the freeing of
   the stack unless the vmap stack can be cached.

 - Provide a mechanism to delay raising signals from atomic context on
   PREEMPT_RT enabled kernels as sighand::lock cannot be acquired. Store
   the information in the task struct and raise it in the exit path.

* tag 'core-core-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  signal, x86: Delay calling signals in atomic on RT enabled kernels
  fork: Use IS_ENABLED() in account_kernel_stack()
  fork: Only cache the VMAP stack in finish_task_switch()
  fork: Move task stack accounting to do_exit()
  fork: Move memcg_charge_kernel_stack() into CONFIG_VMAP_STACK
  fork: Don't assign the stack pointer in dup_task_struct()
  fork, IA64: Provide alloc_thread_stack_node() for IA64
  fork: Duplicate task_struct before stack allocation
  fork: Redo ifdefs around task stack handling
2022-03-21 12:37:33 -07:00
Linus Torvalds
3fd33273a4 Reenable ENQCMD/PASID support:
- Simplify the PASID handling to allocate the PASID once, associate it to
    the mm of a process and free it on mm_exit(). The previous attempt of
    refcounted PASIDs and dynamic alloc()/free() turned out to be error
    prone and too complex. The PASID space is 20bits, so the case of
    resource exhaustion is a pure academic concern.
 
  - Populate the PASID MSR on demand via #GP to avoid racy updates via IPIs.
 
  - Reenable ENQCMD and let objtool check for the forbidden usage of ENQCMD
    in the kernel.
 
  - Update the documentation for Shared Virtual Addressing accordingly.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAmI4WpETHHRnbHhAbGlu
 dXRyb25peC5kZQAKCRCmGPVMDXSYoUfnD/0bY94rgEX4Uuy/mFQ1W8X8XlcyKrha
 0/cRATb+4QV/pwJgGr2nClKhGlFMYPdJLvKMC1TCUPCVrLD1RNmluIZoFzeqXwhm
 jDdCcFOuGZ2D4ujDPWwOOpKBT1ytovnQa7+lH6QJyKkEqdcC2ncOvGJQoiRxRQIG
 8wTVs/OUvQJ5ZhSZQMKQN4uMWMyHEjhbroYS30/uNi/598jTPgzlEoa14XocQ9Os
 nS6ALvjuc9MsJ34F61etMaJU1ZMI3Wx75u9QjEvX6hmJs87YdvgwE7lzJUKFDEuh
 gewM0wp2fTa8/azzP0eMiHTin56PqFdmllzRqXmilbZMEPOeI29dZVArCdpKcAn0
 r9p1kJUT3Xl2G3Oir/OdCaaQHcznD1Y5ZFOyh12wgEucZ/rdeSr7nq7n5HoOL5Bw
 Q2o6YvTkE9DOL0nTN1lSXGiPspou7fzX0uUcRBrbJUS3sBv4zGIlaJXUaTVnSdAt
 VZj4LeOK7v2BjyeiOY0iaaIQd3xjmLUF0UjozXS5M13SoVcToZRbyWqhDzPvNuKA
 imQb/dnFpXhABgmuqAiJLeqM0VtGMFNc780OURkcsBSPng+iSEdV4DzuhK0jpU8x
 Uk1RuGMd/vgmrlDFBrw+orQQiiKR1ixpI0LiHfcOBycfJhqTwcnrNZvAN5/do28Z
 E23+QzlUbZF0cw==
 =Dy8V
 -----END PGP SIGNATURE-----

Merge tag 'x86-pasid-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 PASID support from Thomas Gleixner:
 "Reenable ENQCMD/PASID support:

   - Simplify the PASID handling to allocate the PASID once, associate
     it to the mm of a process and free it on mm_exit().

     The previous attempt of refcounted PASIDs and dynamic
     alloc()/free() turned out to be error prone and too complex. The
     PASID space is 20bits, so the case of resource exhaustion is a pure
     academic concern.

   - Populate the PASID MSR on demand via #GP to avoid racy updates via
     IPIs.

   - Reenable ENQCMD and let objtool check for the forbidden usage of
     ENQCMD in the kernel.

   - Update the documentation for Shared Virtual Addressing accordingly"

* tag 'x86-pasid-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation/x86: Update documentation for SVA (Shared Virtual Addressing)
  tools/objtool: Check for use of the ENQCMD instruction in the kernel
  x86/cpufeatures: Re-enable ENQCMD
  x86/traps: Demand-populate PASID MSR via #GP
  sched: Define and initialize a flag to identify valid PASID in the task
  x86/fpu: Clear PASID when copying fpstate
  iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit
  kernel/fork: Initialize mm's PASID
  iommu/ioasid: Introduce a helper to check for valid PASIDs
  mm: Change CONFIG option for mm->pasid field
  iommu/sva: Rename CONFIG_IOMMU_SVA_LIB to CONFIG_IOMMU_SVA
2022-03-21 12:28:13 -07:00
Suren Baghdasaryan
5c26f6ac94 mm: refactor vm_area_struct::anon_vma_name usage code
Avoid mixing strings and their anon_vma_name referenced pointers by
using struct anon_vma_name whenever possible.  This simplifies the code
and allows easier sharing of anon_vma_name structures when they
represent the same name.

[surenb@google.com: fix comment]

Link: https://lkml.kernel.org/r/20220223153613.835563-1-surenb@google.com
Link: https://lkml.kernel.org/r/20220224231834.1481408-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Colin Cross <ccross@google.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Chris Hyser <chris.hyser@oracle.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Xiaofeng Cao <caoxiaofeng@yulong.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-05 11:08:32 -08:00
Sebastian Andrzej Siewior
0ce055f853 fork: Use IS_ENABLED() in account_kernel_stack()
Not strickly needed but checking CONFIG_VMAP_STACK instead of
task_stack_vm_area()' result allows the compiler the remove the else
path in the CONFIG_VMAP_STACK case where the pointer can't be NULL.

Check for CONFIG_VMAP_STACK in order to use the proper path.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-9-bigeasy@linutronix.de
2022-02-22 22:25:02 +01:00
Sebastian Andrzej Siewior
e540bf3162 fork: Only cache the VMAP stack in finish_task_switch()
The task stack could be deallocated later, but for fork()/exec() kind of
workloads (say a shell script executing several commands) it is important
that the stack is released in finish_task_switch() so that in VMAP_STACK
case it can be cached and reused in the new task.

For PREEMPT_RT it would be good if the wake-up in vfree_atomic() could
be avoided in the scheduling path. Far worse are the other
free_thread_stack() implementations which invoke __free_pages()/
kmem_cache_free() with disabled preemption.

Cache the stack in free_thread_stack() in the VMAP_STACK case and
RCU-delay the free path otherwise. Free the stack in the RCU callback.
In the VMAP_STACK case this is another opportunity to fill the cache.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-8-bigeasy@linutronix.de
2022-02-22 22:25:02 +01:00
Sebastian Andrzej Siewior
1a03d3f13f fork: Move task stack accounting to do_exit()
There is no need to perform the stack accounting of the outgoing task in
its final schedule() invocation which happens with preemption disabled.
The task is leaving, the resources will be freed and the accounting can
happen in do_exit() before the actual schedule invocation which
frees the stack memory.

Move the accounting of the stack memory from release_task_stack() to
exit_task_stack_account() which then can be invoked from do_exit().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-7-bigeasy@linutronix.de
2022-02-22 22:25:02 +01:00
Sebastian Andrzej Siewior
f1c1a9ee00 fork: Move memcg_charge_kernel_stack() into CONFIG_VMAP_STACK
memcg_charge_kernel_stack() is only used in the CONFIG_VMAP_STACK case.

Move memcg_charge_kernel_stack() into the CONFIG_VMAP_STACK block and
invoke it from within alloc_thread_stack_node().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-6-bigeasy@linutronix.de
2022-02-22 22:25:01 +01:00
Sebastian Andrzej Siewior
7865aba3ad fork: Don't assign the stack pointer in dup_task_struct()
All four versions of alloc_thread_stack_node() assign now
task_struct::stack in case the allocation was successful.

Let alloc_thread_stack_node() return an error code instead of the stack
pointer and remove the stack assignment in dup_task_struct().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-5-bigeasy@linutronix.de
2022-02-22 22:25:01 +01:00
Sebastian Andrzej Siewior
2bb0529c0b fork, IA64: Provide alloc_thread_stack_node() for IA64
Provide a generic alloc_thread_stack_node() for IA64 and
CONFIG_ARCH_THREAD_STACK_ALLOCATOR which returns stack pointer and sets
task_struct::stack so it behaves exactly like the other implementations.

Rename IA64's alloc_thread_stack_node() and add the generic version to the
fork code so it is in one place _and_ to drastically lower the chances of
fat fingering the IA64 code.  Do the same for free_thread_stack().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-4-bigeasy@linutronix.de
2022-02-22 22:25:01 +01:00
Sebastian Andrzej Siewior
546c42b2c5 fork: Duplicate task_struct before stack allocation
alloc_thread_stack_node() already populates the task_struct::stack
member except on IA64. The stack pointer is saved and populated again
because IA64 needs it and arch_dup_task_struct() overwrites it.

Allocate thread's stack after task_struct has been duplicated as a
preparation for further changes.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-3-bigeasy@linutronix.de
2022-02-22 22:25:01 +01:00
Sebastian Andrzej Siewior
be9a2277ca fork: Redo ifdefs around task stack handling
The use of ifdef CONFIG_VMAP_STACK is confusing in terms what is
actually happenning and what can happen.

For instance from reading free_thread_stack() it appears that in the
CONFIG_VMAP_STACK case it may receive a non-NULL vm pointer but it may also
be NULL in which case __free_pages() is used to free the stack.  This is
however not the case because in the VMAP case a non-NULL pointer is always
returned here.  Since it looks like this might happen, the compiler creates
the correct dead code with the invocation to __free_pages() and everything
around it. Twice.

Add spaces between the ifdef and the identifer to recognize the ifdef
level which is currently in scope.

Add the current identifer as a comment behind #else and #endif.
Move the code within free_thread_stack() and alloc_thread_stack_node()
into the relevant ifdef blocks.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-2-bigeasy@linutronix.de
2022-02-22 22:25:01 +01:00
Linus Torvalds
0b0894ff78 - Fix task exposure order when forking tasks
-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEEzv7L6UO9uDPlPSfHEsHwGGHeVUoFAmISLs0ACgkQEsHwGGHe
 VUrq+g/+NxLVl3QTmteNh4jEzA/3FDccRKbALNs09YX116nCOZ1sv1Z5FgtdOLUT
 ukIujAm1SKDXQrXoglmm3eH6ylWZ54DQo6qrP+vzavtIKSgbt+vPS63qDR4ehF8N
 Kh04qssWy+AzOSeZRQ6lXTiGei2nBKFbiwlwPnV5vbQmLBFvzv2dEErVFYkHwWN6
 foygRUOhslv5aizwpDriAvDq9ZTVUPXqzIi5zWnTON8y8Vy32eZjSJKez8SQH57w
 vbEZkJTw33tCzG/5+J5mh3UmP9Mcj34W/GDCKHxjO1Y38SbLTMy2Agl5hbRKjVZ8
 W4wElyXyXtLx1RsrZpOJ90mhqwADcxLgkq4ipl6uzikeQlQVnOOBsHZOi3NkTorg
 1YhpxZhqzWWotdGUQwzfZYSuoqQAyUxeqZKwqUD+dYsEqQWhTWSa41IWcfz+r8UD
 uD+pO03EbAEzBB+BSJL9xh0xnchdOnHbpTSFo1AJeQ+LUKanXxO2tXk9/3SwliMj
 M751vPtQH6DiVukSfywxJym+aaLbjeju6RvA69Atap51roYXPSsaCHGDwLeNUS+w
 5D6KC0IuCxsliLpAD4c4PXkRdTvwnG/0lUt+s83bGnyfh5nQzfXXbBp3I5+o0Fcq
 jIQ37uH2Mj5MKtmC8o4ekCtNTtWM8QNZvKzMzoju616Wqee0Ag4=
 =RagE
 -----END PGP SIGNATURE-----

Merge tag 'sched_urgent_for_v5.17_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fix from Borislav Petkov:
 "Fix task exposure order when forking tasks"

* tag 'sched_urgent_for_v5.17_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix yet more sched_fork() races
2022-02-20 12:40:20 -08:00
Linus Torvalds
c1034d249d pidfd.v5.17-rc4
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCYhDKMgAKCRCRxhvAZXjc
 opUwAPwORv7MD8rh5va7LFWUxX1UFpxVILWcC1umuhHAOKZ7YAEA3DTYFrQZhxA2
 nMBR6hBEDKRARIFv3zHZYflYK97FnQA=
 =NPXo
 -----END PGP SIGNATURE-----

Merge tag 'pidfd.v5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull pidfd fix from Christian Brauner:
 "This fixes a problem reported by lockdep when installing a pidfd via
  fd_install() with siglock and the tasklisk write lock held in
  copy_process() when calling clone()/clone3() with CLONE_PIDFD.

  Originally a pidfd was created prior to holding any of these locks but
  this required a call to ksys_close(). So quite some time ago in
  6fd2fe494b ("copy_process(): don't use ksys_close() on cleanups") we
  switched to a get_unused_fd_flags() + fd_install() model.

  As part of that we moved fd_install() as late as possible. This was
  done for two main reasons. First, because we needed to ensure that we
  call fd_install() past the point of no return as once that's called
  the fd is live in the task's file table. Second, because we tried to
  ensure that the fd is visible in /proc/<pid>/fd/<pidfd> right when the
  task is visible.

  This fix moves the fd_install() to an even later point which means
  that a task will be visible in proc while the pidfd isn't yet under
  /proc/<pid>/fd/<pidfd>.

  While this is a user visible change it's very unlikely that this will
  have any impact. Nobody should be relying on that and if they do we
  need to come up with something better but again, it's doubtful this is
  relevant"

* tag 'pidfd.v5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  copy_process(): Move fd_install() out of sighand->siglock critical section
2022-02-20 10:55:05 -08:00
Peter Zijlstra
b1e8206582 sched: Fix yet more sched_fork() races
Where commit 4ef0c5c6b5 ("kernel/sched: Fix sched_fork() access an
invalid sched_task_group") fixed a fork race vs cgroup, it opened up a
race vs syscalls by not placing the task on the runqueue before it
gets exposed through the pidhash.

Commit 13765de814 ("sched/fair: Fix fault in reweight_entity") is
trying to fix a single instance of this, instead fix the whole class
of issues, effectively reverting this commit.

Fixes: 4ef0c5c6b5 ("kernel/sched: Fix sched_fork() access an invalid sched_task_group")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Tested-by: Zhang Qiao <zhangqiao22@huawei.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lkml.kernel.org/r/YgoeCbwj5mbCR0qA@hirez.programming.kicks-ass.net
2022-02-19 11:11:05 +01:00
Eric W. Biederman
8f2f9c4d82 ucounts: Enforce RLIMIT_NPROC not RLIMIT_NPROC+1
Michal Koutný <mkoutny@suse.com> wrote:

> It was reported that v5.14 behaves differently when enforcing
> RLIMIT_NPROC limit, namely, it allows one more task than previously.
> This is consequence of the commit 21d1c5e386 ("Reimplement
> RLIMIT_NPROC on top of ucounts") that missed the sharpness of
> equality in the forking path.

This can be fixed either by fixing the test or by moving the increment
to be before the test.  Fix it my moving copy_creds which contains
the increment before is_ucounts_overlimit.

In the case of CLONE_NEWUSER the ucounts in the task_cred changes.
The function is_ucounts_overlimit needs to use the final version of
the ucounts for the new process.  Which means moving the
is_ucounts_overlimit test after copy_creds is necessary.

Both the test in fork and the test in set_user were semantically
changed when the code moved to ucounts.  The change of the test in
fork was bad because it was before the increment.  The test in
set_user was wrong and the change to ucounts fixed it.  So this
fix only restores the old behavior in one lcation not two.

Link: https://lkml.kernel.org/r/20220204181144.24462-1-mkoutny@suse.com
Link: https://lkml.kernel.org/r/20220216155832.680775-2-ebiederm@xmission.com
Cc: stable@vger.kernel.org
Reported-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Fixes: 21d1c5e386 ("Reimplement RLIMIT_NPROC on top of ucounts")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-02-17 09:10:33 -06:00
Peter Zijlstra
a3d29e8291 sched: Define and initialize a flag to identify valid PASID in the task
Add a new single bit field to the task structure to track whether this task
has initialized the IA32_PASID MSR to the mm's PASID.

Initialize the field to zero when creating a new task with fork/clone.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220207230254.3342514-8-fenghua.yu@intel.com
2022-02-15 11:31:43 +01:00
Fenghua Yu
701fac4038 iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit
PASIDs are process-wide. It was attempted to use refcounted PASIDs to
free them when the last thread drops the refcount. This turned out to
be complex and error prone. Given the fact that the PASID space is 20
bits, which allows up to 1M processes to have a PASID associated
concurrently, PASID resource exhaustion is not a realistic concern.

Therefore, it was decided to simplify the approach and stick with lazy
on demand PASID allocation, but drop the eager free approach and make an
allocated PASID's lifetime bound to the lifetime of the process.

Get rid of the refcounting mechanisms and replace/rename the interfaces
to reflect this new approach.

  [ bp: Massage commit message. ]

Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20220207230254.3342514-6-fenghua.yu@intel.com
2022-02-15 11:31:35 +01:00
Fenghua Yu
a6cbd44093 kernel/fork: Initialize mm's PASID
A new mm doesn't have a PASID yet when it's created. Initialize
the mm's PASID on fork() or for init_mm to INVALID_IOASID (-1).

INIT_PASID (0) is reserved for kernel legacy DMA PASID. It cannot be
allocated to a user process. Initializing the process's PASID to 0 may
cause confusion that's why the process uses the reserved kernel legacy
DMA PASID. Initializing the PASID to INVALID_IOASID (-1) explicitly
tells the process doesn't have a valid PASID yet.

Even though the only user of mm_pasid_init() is in fork.c, define it in
<linux/sched/mm.h> as the first of three mm/pasid life cycle functions
(init/set/drop) to keep these all together.

Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220207230254.3342514-5-fenghua.yu@intel.com
2022-02-14 19:51:47 +01:00
Fenghua Yu
7a853c2d59 mm: Change CONFIG option for mm->pasid field
This currently depends on CONFIG_IOMMU_SUPPORT. But it is only
needed when CONFIG_IOMMU_SVA option is enabled.

Change the CONFIG guards around definition and initialization
of mm->pasid field.

Suggested-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20220207230254.3342514-3-fenghua.yu@intel.com
2022-02-14 19:23:50 +01:00
Waiman Long
ddc204b517
copy_process(): Move fd_install() out of sighand->siglock critical section
I was made aware of the following lockdep splat:

[ 2516.308763] =====================================================
[ 2516.309085] WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
[ 2516.309433] 5.14.0-51.el9.aarch64+debug #1 Not tainted
[ 2516.309703] -----------------------------------------------------
[ 2516.310149] stress-ng/153663 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
[ 2516.310512] ffff0000e422b198 (&newf->file_lock){+.+.}-{2:2}, at: fd_install+0x368/0x4f0
[ 2516.310944]
               and this task is already holding:
[ 2516.311248] ffff0000c08140d8 (&sighand->siglock){-.-.}-{2:2}, at: copy_process+0x1e2c/0x3e80
[ 2516.311804] which would create a new lock dependency:
[ 2516.312066]  (&sighand->siglock){-.-.}-{2:2} -> (&newf->file_lock){+.+.}-{2:2}
[ 2516.312446]
               but this new dependency connects a HARDIRQ-irq-safe lock:
[ 2516.312983]  (&sighand->siglock){-.-.}-{2:2}
   :
[ 2516.330700]  Possible interrupt unsafe locking scenario:

[ 2516.331075]        CPU0                    CPU1
[ 2516.331328]        ----                    ----
[ 2516.331580]   lock(&newf->file_lock);
[ 2516.331790]                                local_irq_disable();
[ 2516.332231]                                lock(&sighand->siglock);
[ 2516.332579]                                lock(&newf->file_lock);
[ 2516.332922]   <Interrupt>
[ 2516.333069]     lock(&sighand->siglock);
[ 2516.333291]
                *** DEADLOCK ***
[ 2516.389845]
               stack backtrace:
[ 2516.390101] CPU: 3 PID: 153663 Comm: stress-ng Kdump: loaded Not tainted 5.14.0-51.el9.aarch64+debug #1
[ 2516.390756] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
[ 2516.391155] Call trace:
[ 2516.391302]  dump_backtrace+0x0/0x3e0
[ 2516.391518]  show_stack+0x24/0x30
[ 2516.391717]  dump_stack_lvl+0x9c/0xd8
[ 2516.391938]  dump_stack+0x1c/0x38
[ 2516.392247]  print_bad_irq_dependency+0x620/0x710
[ 2516.392525]  check_irq_usage+0x4fc/0x86c
[ 2516.392756]  check_prev_add+0x180/0x1d90
[ 2516.392988]  validate_chain+0x8e0/0xee0
[ 2516.393215]  __lock_acquire+0x97c/0x1e40
[ 2516.393449]  lock_acquire.part.0+0x240/0x570
[ 2516.393814]  lock_acquire+0x90/0xb4
[ 2516.394021]  _raw_spin_lock+0xe8/0x154
[ 2516.394244]  fd_install+0x368/0x4f0
[ 2516.394451]  copy_process+0x1f5c/0x3e80
[ 2516.394678]  kernel_clone+0x134/0x660
[ 2516.394895]  __do_sys_clone3+0x130/0x1f4
[ 2516.395128]  __arm64_sys_clone3+0x5c/0x7c
[ 2516.395478]  invoke_syscall.constprop.0+0x78/0x1f0
[ 2516.395762]  el0_svc_common.constprop.0+0x22c/0x2c4
[ 2516.396050]  do_el0_svc+0xb0/0x10c
[ 2516.396252]  el0_svc+0x24/0x34
[ 2516.396436]  el0t_64_sync_handler+0xa4/0x12c
[ 2516.396688]  el0t_64_sync+0x198/0x19c
[ 2517.491197] NET: Registered PF_ATMPVC protocol family
[ 2517.491524] NET: Registered PF_ATMSVC protocol family
[ 2591.991877] sched: RT throttling activated

One way to solve this problem is to move the fd_install() call out of
the sighand->siglock critical section.

Before commit 6fd2fe494b ("copy_process(): don't use ksys_close()
on cleanups"), the pidfd installation was done without holding both
the task_list lock and the sighand->siglock. Obviously, holding these
two locks are not really needed to protect the fd_install() call.
So move the fd_install() call down to after the releases of both locks.

Link: https://lore.kernel.org/r/20220208163912.1084752-1-longman@redhat.com
Fixes: 6fd2fe494b ("copy_process(): don't use ksys_close() on cleanups")
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2022-02-11 09:28:32 +01:00
Linus Torvalds
35ce8ae9ae Merge branch 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull signal/exit/ptrace updates from Eric Biederman:
 "This set of changes deletes some dead code, makes a lot of cleanups
  which hopefully make the code easier to follow, and fixes bugs found
  along the way.

  The end-game which I have not yet reached yet is for fatal signals
  that generate coredumps to be short-circuit deliverable from
  complete_signal, for force_siginfo_to_task not to require changing
  userspace configured signal delivery state, and for the ptrace stops
  to always happen in locations where we can guarantee on all
  architectures that the all of the registers are saved and available on
  the stack.

  Removal of profile_task_ext, profile_munmap, and profile_handoff_task
  are the big successes for dead code removal this round.

  A bunch of small bug fixes are included, as most of the issues
  reported were small enough that they would not affect bisection so I
  simply added the fixes and did not fold the fixes into the changes
  they were fixing.

  There was a bug that broke coredumps piped to systemd-coredump. I
  dropped the change that caused that bug and replaced it entirely with
  something much more restrained. Unfortunately that required some
  rebasing.

  Some successes after this set of changes: There are few enough calls
  to do_exit to audit in a reasonable amount of time. The lifetime of
  struct kthread now matches the lifetime of struct task, and the
  pointer to struct kthread is no longer stored in set_child_tid. The
  flag SIGNAL_GROUP_COREDUMP is removed. The field group_exit_task is
  removed. Issues where task->exit_code was examined with
  signal->group_exit_code should been examined were fixed.

  There are several loosely related changes included because I am
  cleaning up and if I don't include them they will probably get lost.

  The original postings of these changes can be found at:
     https://lkml.kernel.org/r/87a6ha4zsd.fsf@email.froward.int.ebiederm.org
     https://lkml.kernel.org/r/87bl1kunjj.fsf@email.froward.int.ebiederm.org
     https://lkml.kernel.org/r/87r19opkx1.fsf_-_@email.froward.int.ebiederm.org

  I trimmed back the last set of changes to only the obviously correct
  once. Simply because there was less time for review than I had hoped"

* 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (44 commits)
  ptrace/m68k: Stop open coding ptrace_report_syscall
  ptrace: Remove unused regs argument from ptrace_report_syscall
  ptrace: Remove second setting of PT_SEIZED in ptrace_attach
  taskstats: Cleanup the use of task->exit_code
  exit: Use the correct exit_code in /proc/<pid>/stat
  exit: Fix the exit_code for wait_task_zombie
  exit: Coredumps reach do_group_exit
  exit: Remove profile_handoff_task
  exit: Remove profile_task_exit & profile_munmap
  signal: clean up kernel-doc comments
  signal: Remove the helper signal_group_exit
  signal: Rename group_exit_task group_exec_task
  coredump: Stop setting signal->group_exit_task
  signal: Remove SIGNAL_GROUP_COREDUMP
  signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process
  signal: Make coredump handling explicit in complete_signal
  signal: Have prepare_signal detect coredumps using signal->core_state
  signal: Have the oom killer detect coredumps using signal->core_state
  exit: Move force_uaccess back into do_exit
  exit: Guarantee make_task_dead leaks the tsk when calling do_task_exit
  ...
2022-01-17 05:49:30 +02:00
Linus Torvalds
f56caedaf9 Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton:
 "146 patches.

  Subsystems affected by this patch series: kthread, ia64, scripts,
  ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
  dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
  memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
  userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
  ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
  damon)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (146 commits)
  mm/damon: hide kernel pointer from tracepoint event
  mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
  mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
  mm/damon/dbgfs: remove an unnecessary variable
  mm/damon: move the implementation of damon_insert_region to damon.h
  mm/damon: add access checking for hugetlb pages
  Docs/admin-guide/mm/damon/usage: update for schemes statistics
  mm/damon/dbgfs: support all DAMOS stats
  Docs/admin-guide/mm/damon/reclaim: document statistics parameters
  mm/damon/reclaim: provide reclamation statistics
  mm/damon/schemes: account how many times quota limit has exceeded
  mm/damon/schemes: account scheme actions that successfully applied
  mm/damon: remove a mistakenly added comment for a future feature
  Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
  Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
  Docs/admin-guide/mm/damon/usage: remove redundant information
  Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
  mm/damon: convert macro functions to static inline functions
  mm/damon: modify damon_rand() macro to static inline function
  mm/damon: move damon_rand() definition into damon.h
  ...
2022-01-15 20:37:06 +02:00
Arnd Bergmann
17fca131ce mm: move anon_vma declarations to linux/mm_inline.h
The patch to add anonymous vma names causes a build failure in some
configurations:

  include/linux/mm_types.h: In function 'is_same_vma_anon_name':
  include/linux/mm_types.h:924:37: error: implicit declaration of function 'strcmp' [-Werror=implicit-function-declaration]
    924 |         return name && vma_name && !strcmp(name, vma_name);
        |                                     ^~~~~~
  include/linux/mm_types.h:22:1: note: 'strcmp' is defined in header '<string.h>'; did you forget to '#include <string.h>'?

This should not really be part of linux/mm_types.h in the first place,
as that header is meant to only contain structure defintions and need a
minimum set of indirect includes itself.

While the header clearly includes more than it should at this point,
let's not make it worse by including string.h as well, which would pull
in the expensive (compile-speed wise) fortify-string logic.

Move the new functions into a separate header that only needs to be
included in a couple of locations.

Link: https://lkml.kernel.org/r/20211207125710.2503446-1-arnd@kernel.org
Fixes: "mm: add a field to store names for private anonymous memory"
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Colin Cross <ccross@google.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-15 16:30:27 +02:00
Colin Cross
9a10064f56 mm: add a field to store names for private anonymous memory
In many userspace applications, and especially in VM based applications
like Android uses heavily, there are multiple different allocators in
use.  At a minimum there is libc malloc and the stack, and in many cases
there are libc malloc, the stack, direct syscalls to mmap anonymous
memory, and multiple VM heaps (one for small objects, one for big
objects, etc.).  Each of these layers usually has its own tools to
inspect its usage; malloc by compiling a debug version, the VM through
heap inspection tools, and for direct syscalls there is usually no way
to track them.

On Android we heavily use a set of tools that use an extended version of
the logic covered in Documentation/vm/pagemap.txt to walk all pages
mapped in userspace and slice their usage by process, shared (COW) vs.
unique mappings, backing, etc.  This can account for real physical
memory usage even in cases like fork without exec (which Android uses
heavily to share as many private COW pages as possible between
processes), Kernel SamePage Merging, and clean zero pages.  It produces
a measurement of the pages that only exist in that process (USS, for
unique), and a measurement of the physical memory usage of that process
with the cost of shared pages being evenly split between processes that
share them (PSS).

If all anonymous memory is indistinguishable then figuring out the real
physical memory usage (PSS) of each heap requires either a pagemap
walking tool that can understand the heap debugging of every layer, or
for every layer's heap debugging tools to implement the pagemap walking
logic, in which case it is hard to get a consistent view of memory
across the whole system.

Tracking the information in userspace leads to all sorts of problems.
It either needs to be stored inside the process, which means every
process has to have an API to export its current heap information upon
request, or it has to be stored externally in a filesystem that somebody
needs to clean up on crashes.  It needs to be readable while the process
is still running, so it has to have some sort of synchronization with
every layer of userspace.  Efficiently tracking the ranges requires
reimplementing something like the kernel vma trees, and linking to it
from every layer of userspace.  It requires more memory, more syscalls,
more runtime cost, and more complexity to separately track regions that
the kernel is already tracking.

This patch adds a field to /proc/pid/maps and /proc/pid/smaps to show a
userspace-provided name for anonymous vmas.  The names of named
anonymous vmas are shown in /proc/pid/maps and /proc/pid/smaps as
[anon:<name>].

Userspace can set the name for a region of memory by calling

   prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned long)name)

Setting the name to NULL clears it.  The name length limit is 80 bytes
including NUL-terminator and is checked to contain only printable ascii
characters (including space), except '[',']','\','$' and '`'.

Ascii strings are being used to have a descriptive identifiers for vmas,
which can be understood by the users reading /proc/pid/maps or
/proc/pid/smaps.  Names can be standardized for a given system and they
can include some variable parts such as the name of the allocator or a
library, tid of the thread using it, etc.

The name is stored in a pointer in the shared union in vm_area_struct
that points to a null terminated string.  Anonymous vmas with the same
name (equivalent strings) and are otherwise mergeable will be merged.
The name pointers are not shared between vmas even if they contain the
same name.  The name pointer is stored in a union with fields that are
only used on file-backed mappings, so it does not increase memory usage.

CONFIG_ANON_VMA_NAME kernel configuration is introduced to enable this
feature.  It keeps the feature disabled by default to prevent any
additional memory overhead and to avoid confusing procfs parsers on
systems which are not ready to support named anonymous vmas.

The patch is based on the original patch developed by Colin Cross, more
specifically on its latest version [1] posted upstream by Sumit Semwal.
It used a userspace pointer to store vma names.  In that design, name
pointers could be shared between vmas.  However during the last
upstreaming attempt, Kees Cook raised concerns [2] about this approach
and suggested to copy the name into kernel memory space, perform
validity checks [3] and store as a string referenced from
vm_area_struct.

One big concern is about fork() performance which would need to strdup
anonymous vma names.  Dave Hansen suggested experimenting with
worst-case scenario of forking a process with 64k vmas having longest
possible names [4].  I ran this experiment on an ARM64 Android device
and recorded a worst-case regression of almost 40% when forking such a
process.

This regression is addressed in the followup patch which replaces the
pointer to a name with a refcounted structure that allows sharing the
name pointer between vmas of the same name.  Instead of duplicating the
string during fork() or when splitting a vma it increments the refcount.

[1] https://lore.kernel.org/linux-mm/20200901161459.11772-4-sumit.semwal@linaro.org/
[2] https://lore.kernel.org/linux-mm/202009031031.D32EF57ED@keescook/
[3] https://lore.kernel.org/linux-mm/202009031022.3834F692@keescook/
[4] https://lore.kernel.org/linux-mm/5d0358ab-8c47-2f5f-8e43-23b89d6a8e95@intel.com/

Changes for prctl(2) manual page (in the options section):

PR_SET_VMA
	Sets an attribute specified in arg2 for virtual memory areas
	starting from the address specified in arg3 and spanning the
	size specified	in arg4. arg5 specifies the value of the attribute
	to be set. Note that assigning an attribute to a virtual memory
	area might prevent it from being merged with adjacent virtual
	memory areas due to the difference in that attribute's value.

	Currently, arg2 must be one of:

	PR_SET_VMA_ANON_NAME
		Set a name for anonymous virtual memory areas. arg5 should
		be a pointer to a null-terminated string containing the
		name. The name length including null byte cannot exceed
		80 bytes. If arg5 is NULL, the name of the appropriate
		anonymous virtual memory areas will be reset. The name
		can contain only printable ascii characters (including
                space), except '[',']','\','$' and '`'.

                This feature is available only if the kernel is built with
                the CONFIG_ANON_VMA_NAME option enabled.

[surenb@google.com: docs: proc.rst: /proc/PID/maps: fix malformed table]
  Link: https://lkml.kernel.org/r/20211123185928.2513763-1-surenb@google.com
[surenb: rebased over v5.15-rc6, replaced userpointer with a kernel copy,
 added input sanitization and CONFIG_ANON_VMA_NAME config. The bulk of the
 work here was done by Colin Cross, therefore, with his permission, keeping
 him as the author]

Link: https://lkml.kernel.org/r/20211019215511.3771969-2-surenb@google.com
Signed-off-by: Colin Cross <ccross@google.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Glauber <jan.glauber@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Landley <rob@landley.net>
Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com>
Cc: Shaohua Li <shli@fusionio.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-15 16:30:27 +02:00
Eric W. Biederman
2873cd31a2 exit: Remove profile_handoff_task
All profile_handoff_task does is notify the task_free_notifier chain.
The helpers task_handoff_register and task_handoff_unregister are used
to add and delete entries from that chain and are never called.

So remove the dead code and make it much easier to read and reason
about __put_task_struct.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/87fspyw6m0.fsf@email.froward.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-01-08 12:43:57 -06:00
Eric W. Biederman
e32cf5dfbe kthread: Generalize pf_io_worker so it can point to struct kthread
The point of using set_child_tid to hold the kthread pointer was that
it already did what is necessary.  There are now restrictions on when
set_child_tid can be initialized and when set_child_tid can be used in
schedule_tail.  Which indicates that continuing to use set_child_tid
to hold the kthread pointer is a bad idea.

Instead of continuing to use the set_child_tid field of task_struct
generalize the pf_io_worker field of task_struct and use it to hold
the kthread pointer.

Rename pf_io_worker (which is a void * pointer) to worker_private so
it can be used to store kthreads struct kthread pointer.  Update the
kthread code to store the kthread pointer in the worker_private field.
Remove the places where set_child_tid had to be dealt with carefully
because kthreads also used it.

Link: https://lkml.kernel.org/r/CAHk-=wgtFAA9SbVYg0gR1tqPMC17-NYcs0GQkaYg1bGhh1uJQQ@mail.gmail.com
Link: https://lkml.kernel.org/r/87a6grvqy8.fsf_-_@email.froward.int.ebiederm.org
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-01-08 09:39:49 -06:00
Eric W. Biederman
ff8288ff47 fork: Rename bad_fork_cleanup_threadgroup_lock to bad_fork_cleanup_delayacct
I just fixed a bug in copy_process when using the label
bad_fork_cleanup_threadgroup_lock.  While fixing the bug I looked
closer at the label and realized it has been misnamed since
568ac88821 ("cgroup: reduce read locked section of
cgroup_threadgroup_rwsem during fork").

Fix the name so that fork is easier to understand.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-12-20 10:51:00 -06:00
Eric W. Biederman
6692c98c7d fork: Stop protecting back_fork_cleanup_cgroup_lock with CONFIG_NUMA
Mark Brown <broonie@kernel.org> reported:

> This is also causing further build errors including but not limited to:
>
> /tmp/next/build/kernel/fork.c: In function 'copy_process':
> /tmp/next/build/kernel/fork.c:2106:4: error: label 'bad_fork_cleanup_threadgroup_lock' used but not defined
>  2106 |    goto bad_fork_cleanup_threadgroup_lock;
>       |    ^~~~

It turns out that I messed up and was depending upon a label protected
by an ifdef.  Move the label out of the ifdef as the ifdef around the label
no longer makes sense (if it ever did).

Link: https://lkml.kernel.org/r/YbugCP144uxXvRsk@sirena.org.uk
Fixes: 40966e316f ("kthread: Ensure struct kthread is present for all kthreads")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-12-20 10:50:51 -06:00
Eric W. Biederman
40966e316f kthread: Ensure struct kthread is present for all kthreads
Today the rules are a bit iffy and arbitrary about which kernel
threads have struct kthread present.  Both idle threads and thread
started with create_kthread want struct kthread present so that is
effectively all kernel threads.  Make the rule that if PF_KTHREAD
and the task is running then struct kthread is present.

This will allow the kernel thread code to using tsk->exit_code
with different semantics from ordinary processes.

To make ensure that struct kthread is present for all
kernel threads move it's allocation into copy_process.

Add a deallocation of struct kthread in exec for processes
that were kernel threads.

Move the allocation of struct kthread for the initial thread
earlier so that it is not repeated for each additional idle
thread.

Move the initialization of struct kthread into set_kthread_struct
so that the structure is always and reliably initailized.

Clear set_child_tid in free_kthread_struct to ensure the kthread
struct is reliably freed during exec.  The function
free_kthread_struct does not need to clear vfork_done during exec as
exec_mm_release called from exec_mmap has already cleared vfork_done.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-12-13 12:04:45 -06:00
Christoph Hellwig
88c9a2ce52 fork: move copy_io to block/blk-ioc.c
Move the copying of the I/O context to the block layer as that is where
we can use the proper low-level interfaces.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-29 06:41:29 -07:00
Linus Torvalds
622c72b651 A single fix for POSIX CPU timers to address a problem where POSIX CPU
timer delivery stops working for a new child task because copy_process()
 copies state information which is only valid for the parent task.
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAmGRDVUTHHRnbHhAbGlu
 dXRyb25peC5kZQAKCRCmGPVMDXSYocOFD/42NOdli73N+Jdq7APHUIHXzu+6DVT6
 CI5toLQw+0KPoF0s1wg4+J0YCDt2k0Pu4lOabF3Ze/+c6RlR5zfCXESqsXdHaCjh
 E91Vs57u0ataRMEHo6KB6eBIutuF8hyxfY6vVXfkTRNAreUIWiwWYrlB0G64JVOG
 +/l1W7adovjLcLwcW+ArrnLJwkBKtXunK6PVv2IrdRHwpMHbwoNRCCCFvzkqnWmQ
 4Yy2/NaB/PEBK5kezP1/j9EMcGCTWk1JJIm+l/PEwCCcbIgIdUahpW3XHAaqms6R
 oukqCvE5ukfmVzBFYBhCamhF8heyEeBVRqGU+Yyk48+I+DQFBCqaqa1NKSuEUdNL
 Nycy6Rp1yn7CHVSB461shMS6NJGOSNDBjv7vxer3WjV3HPJu7y0RrN7jXbkSfQnm
 hVKjkmbDEYwylgzFE5+T857NqD5MEXeuIBtTO08hNRnpd61aB3x+qq+8ElE6ST8Y
 pm6rMzw0AZ5buPK8QdGVDk0dD4WKObj1LzmRZvBtYeWynO6sxyKUl6B2CgAxrvn5
 D1Li2/arkJMCVeIuIL5uE6DPoxSh8J7OuEC4KeWX8M8xQSEDImqfZ+tDL2Esv6jv
 xDmymq584hiCBc1CJjCOA9kZYe6KNXC7lkVOns6GaKKzLhkrcvUR3dUGhMyzxAMO
 t9QIAinR6JwRRA==
 =EBbc
 -----END PGP SIGNATURE-----

Merge tag 'timers-urgent-2021-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fix from Thomas Gleixner:
 "A single fix for POSIX CPU timers to address a problem where POSIX CPU
  timer delivery stops working for a new child task because
  copy_process() copies state information which is only valid for the
  parent task"

* tag 'timers-urgent-2021-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  posix-cpu-timers: Clear task::posix_cputimers_work in copy_process()
2021-11-14 10:43:38 -08:00
Linus Torvalds
59a2ceeef6 Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
 "87 patches.

  Subsystems affected by this patch series: mm (pagecache and hugetlb),
  procfs, misc, MAINTAINERS, lib, checkpatch, binfmt, kallsyms, ramfs,
  init, codafs, nilfs2, hfs, crash_dump, signals, seq_file, fork,
  sysvfs, kcov, gdb, resource, selftests, and ipc"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (87 commits)
  ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL
  ipc: check checkpoint_restore_ns_capable() to modify C/R proc files
  selftests/kselftest/runner/run_one(): allow running non-executable files
  virtio-mem: disallow mapping virtio-mem memory via /dev/mem
  kernel/resource: disallow access to exclusive system RAM regions
  kernel/resource: clean up and optimize iomem_is_exclusive()
  scripts/gdb: handle split debug for vmlinux
  kcov: replace local_irq_save() with a local_lock_t
  kcov: avoid enable+disable interrupts if !in_task()
  kcov: allocate per-CPU memory on the relevant node
  Documentation/kcov: define `ip' in the example
  Documentation/kcov: include types.h in the example
  sysv: use BUILD_BUG_ON instead of runtime check
  kernel/fork.c: unshare(): use swap() to make code cleaner
  seq_file: fix passing wrong private data
  seq_file: move seq_escape() to a header
  signal: remove duplicate include in signal.h
  crash_dump: remove duplicate include in crash_dump.h
  crash_dump: fix boolreturn.cocci warning
  hfs/hfsplus: use WARN_ON for sanity check
  ...
2021-11-09 10:11:53 -08:00
Ran Xiaokai
ba1f70ddd1 kernel/fork.c: unshare(): use swap() to make code cleaner
Use swap() instead of reimplementing it.

Link: https://lkml.kernel.org/r/20210909022046.8151-1-ran.xiaokai@zte.com.cn
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Cc: Gabriel Krisman Bertazi <krisman@collabora.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexey Gladkov <legion@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-11-09 10:02:52 -08:00
Linus Torvalds
a602285ac1 Merge branch 'per_signal_struct_coredumps-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull per signal_struct coredumps from Eric Biederman:
 "Current coredumps are mixed up with the exit code, the signal handling
  code, and the ptrace code making coredumps much more complicated than
  necessary and difficult to follow.

  This series of changes starts with ptrace_stop and cleans it up,
  making it easier to follow what is happening in ptrace_stop. Then
  cleans up the exec interactions with coredumps. Then cleans up the
  coredump interactions with exit. Finally the coredump interactions
  with the signal handling code is cleaned up.

  The first and last changes are bug fixes for minor bugs.

  I believe the fact that vfork followed by execve can kill the process
  the called vfork if exec fails is sufficient justification to change
  the userspace visible behavior.

  In previous discussions some of these changes were organized
  differently and individually appeared to make the code base worse. As
  currently written I believe they all stand on their own as cleanups
  and bug fixes.

  Which means that even if the worst should happen and the last change
  needs to be reverted for some unimaginable reason, the code base will
  still be improved.

  If the worst does not happen there are a more cleanups that can be
  made. Signals that generate coredumps can easily become eligible for
  short circuit delivery in complete_signal. The entire rendezvous for
  generating a coredump can move into get_signal. The function
  force_sig_info_to_task be written in a way that does not modify the
  signal handling state of the target task (because coredumps are
  eligible for short circuit delivery). Many of these future cleanups
  can be done another way but nothing so cleanly as if coredumps become
  per signal_struct"

* 'per_signal_struct_coredumps-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  coredump: Limit coredumps to a single thread group
  coredump:  Don't perform any cleanups before dumping core
  exit: Factor coredump_exit_mm out of exit_mm
  exec: Check for a pending fatal signal instead of core_state
  ptrace: Remove the unnecessary arguments from arch_ptrace_stop
  signal: Remove the bogus sigkill_pending in ptrace_stop
2021-11-03 12:15:29 -07:00
Michael Pratt
ca7752caea posix-cpu-timers: Clear task::posix_cputimers_work in copy_process()
copy_process currently copies task_struct.posix_cputimers_work as-is. If a
timer interrupt arrives while handling clone and before dup_task_struct
completes then the child task will have:

1. posix_cputimers_work.scheduled = true
2. posix_cputimers_work.work queued.

copy_process clears task_struct.task_works, so (2) will have no effect and
posix_cpu_timers_work will never run (not to mention it doesn't make sense
for two tasks to share a common linked list).

Since posix_cpu_timers_work never runs, posix_cputimers_work.scheduled is
never cleared. Since scheduled is set, future timer interrupts will skip
scheduling work, with the ultimate result that the task will never receive
timer expirations.

Together, the complete flow is:

1. Task 1 calls clone(), enters kernel.
2. Timer interrupt fires, schedules task work on Task 1.
   2a. task_struct.posix_cputimers_work.scheduled = true
   2b. task_struct.posix_cputimers_work.work added to
       task_struct.task_works.
3. dup_task_struct() copies Task 1 to Task 2.
4. copy_process() clears task_struct.task_works for Task 2.
5. Future timer interrupts on Task 2 see
   task_struct.posix_cputimers_work.scheduled = true and skip scheduling
   work.

Fix this by explicitly clearing contents of task_struct.posix_cputimers_work
in copy_process(). This was never meant to be shared or inherited across
tasks in the first place.

Fixes: 1fb497dd00 ("posix-cpu-timers: Provide mechanisms to defer timer handling to task_work")
Reported-by: Rhys Hiltner <rhys@justin.tv>
Signed-off-by: Michael Pratt <mpratt@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20211101210615.716522-1-mpratt@google.com
2021-11-02 12:52:17 +01:00
Linus Torvalds
9a7e0a90a4 Scheduler updates:
- Revert the printk format based wchan() symbol resolution as it can leak
    the raw value in case that the symbol is not resolvable.
 
  - Make wchan() more robust and work with all kind of unwinders by
    enforcing that the task stays blocked while unwinding is in progress.
 
  - Prevent sched_fork() from accessing an invalid sched_task_group
 
  - Improve asymmetric packing logic
 
  - Extend scheduler statistics to RT and DL scheduling classes and add
    statistics for bandwith burst to the SCHED_FAIR class.
 
  - Properly account SCHED_IDLE entities
 
  - Prevent a potential deadlock when initial priority is assigned to a
    newly created kthread. A recent change to plug a race between cpuset and
    __sched_setscheduler() introduced a new lock dependency which is now
    triggered. Break the lock dependency chain by moving the priority
    assignment to the thread function.
 
  - Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.
 
  - Improve idle balancing in general and especially for NOHZ enabled
    systems.
 
  - Provide proper interfaces for live patching so it does not have to
    fiddle with scheduler internals.
 
  - Add cluster aware scheduling support.
 
  - A small set of tweaks for RT (irqwork, wait_task_inactive(), various
    scheduler options and delaying mmdrop)
 
  - The usual small tweaks and improvements all over the place
 -----BEGIN PGP SIGNATURE-----
 
 iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAmF/OUkTHHRnbHhAbGlu
 dXRyb25peC5kZQAKCRCmGPVMDXSYoR/5D/9ikdGNpKg9osNqJ3GjAmxsK6kVkB29
 iFe2k8pIpWDToWQf/wQRGih4Yj3Cl49QSnZcPIibh2/12EB1qrrW6iSPJkInz8Ec
 /1LS5/Vewn2OyoxyXZjdvGC5gTXEodSbIazASvX7nvdMeI4gsAsL5etzrMJirT/t
 aymqvr7zovvywrwMTQJrGjUMo9l4ewE8tafMNNhRu1BHU1U4ojM9yvThyRAAcmp7
 3Xy49A+Yq3IgrvYI4u8FMK5Zh08KaxSFjiLhePGm/bF+wSfYmWop2TP1jY05W2Uo
 ti8hfbJMUoFRYuMxAiEldkItnc0wV4M9PtWZZ/x+B71bs65Y4Zjt9cW+rxJv2+m1
 vzV31EsQwGnOti072dzWN4c/cZqngVXAjaNtErvDwJUr+Tw1ayv9KUvuodMQqZY6
 mu68bFUO2kV9EMe1CBOv51Uy1RGHyLj3rlNqrkw+Xp5ISE9Ad2vhUEiRp5bQx5Ci
 V/XFhGZkGUluh0vccrdFlNYZwhj8cZEzkOPCnPSeZ+bq8SyZE6xuHH/lTP1CJCOy
 s800rW1huM+kgV+zRN8adDkGXibAk9N3RtVGnQXmuEy8gB9LZmQg+JeM2wsc9B+6
 i0gdqZnsjNAfoK+BBAG4holxptSL8/eOJsFH8ZNIoxQ+iqooyPx9tFX7yXnRTBQj
 d2qWG7UvoseT+g==
 =fgtS
 -----END PGP SIGNATURE-----

Merge tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Thomas Gleixner:

 - Revert the printk format based wchan() symbol resolution as it can
   leak the raw value in case that the symbol is not resolvable.

 - Make wchan() more robust and work with all kind of unwinders by
   enforcing that the task stays blocked while unwinding is in progress.

 - Prevent sched_fork() from accessing an invalid sched_task_group

 - Improve asymmetric packing logic

 - Extend scheduler statistics to RT and DL scheduling classes and add
   statistics for bandwith burst to the SCHED_FAIR class.

 - Properly account SCHED_IDLE entities

 - Prevent a potential deadlock when initial priority is assigned to a
   newly created kthread. A recent change to plug a race between cpuset
   and __sched_setscheduler() introduced a new lock dependency which is
   now triggered. Break the lock dependency chain by moving the priority
   assignment to the thread function.

 - Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.

 - Improve idle balancing in general and especially for NOHZ enabled
   systems.

 - Provide proper interfaces for live patching so it does not have to
   fiddle with scheduler internals.

 - Add cluster aware scheduling support.

 - A small set of tweaks for RT (irqwork, wait_task_inactive(), various
   scheduler options and delaying mmdrop)

 - The usual small tweaks and improvements all over the place

* tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (69 commits)
  sched/fair: Cleanup newidle_balance
  sched/fair: Remove sysctl_sched_migration_cost condition
  sched/fair: Wait before decaying max_newidle_lb_cost
  sched/fair: Skip update_blocked_averages if we are defering load balance
  sched/fair: Account update_blocked_averages in newidle_balance cost
  x86: Fix __get_wchan() for !STACKTRACE
  sched,x86: Fix L2 cache mask
  sched/core: Remove rq_relock()
  sched: Improve wake_up_all_idle_cpus() take #2
  irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT
  irq_work: Handle some irq_work in a per-CPU thread on PREEMPT_RT
  irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.
  sched/rt: Annotate the RT balancing logic irqwork as IRQ_WORK_HARD_IRQ
  sched: Add cluster scheduler level for x86
  sched: Add cluster scheduler level in core and related Kconfig for ARM64
  topology: Represent clusters of CPUs within a die
  sched: Disable -Wunused-but-set-variable
  sched: Add wrapper for get_wchan() to keep task blocked
  x86: Fix get_wchan() to support the ORC unwinder
  proc: Use task_is_running() for wchan in /proc/$pid/stat
  ...
2021-11-01 13:48:52 -07:00
Christoph Hellwig
545c6647d2 kernel: remove spurious blkdev.h includes
Various files have acquired spurious includes of <linux/blkdev.h> over
time.  Remove them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210920123328.1399408-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18 06:17:01 -06:00
Zhang Qiao
4ef0c5c6b5 kernel/sched: Fix sched_fork() access an invalid sched_task_group
There is a small race between copy_process() and sched_fork()
where child->sched_task_group point to an already freed pointer.

	parent doing fork()      | someone moving the parent
				 | to another cgroup
  -------------------------------+-------------------------------
  copy_process()
      + dup_task_struct()<1>
				  parent move to another cgroup,
				  and free the old cgroup. <2>
      + sched_fork()
	+ __set_task_cpu()<3>
	+ task_fork_fair()
	  + sched_slice()<4>

In the worst case, this bug can lead to "use-after-free" and
cause panic as shown above:

  (1) parent copy its sched_task_group to child at <1>;

  (2) someone move the parent to another cgroup and free the old
      cgroup at <2>;

  (3) the sched_task_group and cfs_rq that belong to the old cgroup
      will be accessed at <3> and <4>, which cause a panic:

  [] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
  [] PGD 8000001fa0a86067 P4D 8000001fa0a86067 PUD 2029955067 PMD 0
  [] Oops: 0000 [#1] SMP PTI
  [] CPU: 7 PID: 648398 Comm: ebizzy Kdump: loaded Tainted: G           OE    --------- -  - 4.18.0.x86_64+ #1
  [] RIP: 0010:sched_slice+0x84/0xc0

  [] Call Trace:
  []  task_fork_fair+0x81/0x120
  []  sched_fork+0x132/0x240
  []  copy_process.part.5+0x675/0x20e0
  []  ? __handle_mm_fault+0x63f/0x690
  []  _do_fork+0xcd/0x3b0
  []  do_syscall_64+0x5d/0x1d0
  []  entry_SYSCALL_64_after_hwframe+0x65/0xca
  [] RIP: 0033:0x7f04418cd7e1

Between cgroup_can_fork() and cgroup_post_fork(), the cgroup
membership and thus sched_task_group can't change. So update child's
sched_task_group at sched_post_fork() and move task_fork() and
__set_task_cpu() (where accees the sched_task_group) from sched_fork()
to sched_post_fork().

Fixes: 8323f26ce3 ("sched: Fix race in task_group")
Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lkml.kernel.org/r/20210915064030.2231-1-zhangqiao22@huawei.com
2021-10-14 13:09:58 +02:00
Eric W. Biederman
0258b5fd7c coredump: Limit coredumps to a single thread group
Today when a signal is delivered with a handler of SIG_DFL whose
default behavior is to generate a core dump not only that process but
every process that shares the mm is killed.

In the case of vfork this looks like a real world problem.  Consider
the following well defined sequence.

	if (vfork() == 0) {
		execve(...);
		_exit(EXIT_FAILURE);
	}

If a signal that generates a core dump is received after vfork but
before the execve changes the mm the process that called vfork will
also be killed (as the mm is shared).

Similarly if the execve fails after the point of no return the kernel
delivers SIGSEGV which will kill both the exec'ing process and because
the mm is shared the process that called vfork as well.

As far as I can tell this behavior is a violation of people's
reasonable expectations, POSIX, and is unnecessarily fragile when the
system is low on memory.

Solve this by making a userspace visible change to only kill a single
process/thread group.  This is possible because Jann Horn recently
modified[1] the coredump code so that the mm can safely be modified
while the coredump is happening.  With LinuxThreads long gone I don't
expect anyone to have a notice this behavior change in practice.

To accomplish this move the core_state pointer from mm_struct to
signal_struct, which allows different thread groups to coredump
simultatenously.

In zap_threads remove the work to kill anything except for the current
thread group.

v2: Remove core_state from the VM_BUG_ON_MM print to fix
    compile failure when CONFIG_DEBUG_VM is enabled.
    Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>

[1] a07279c9a8 ("binfmt_elf, binfmt_elf_fdpic: use a VMA list snapshot")
Fixes: d89f3847def4 ("[PATCH] thread-aware coredumps, 2.5.43-C3")
History-tree: git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Link: https://lkml.kernel.org/r/87y27mvnke.fsf@disp2133
Link: https://lkml.kernel.org/r/20211007144701.67592574@canb.auug.org.au
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-10-08 12:06:02 -05:00
Eric W. Biederman
9230738308 coredump: Don't perform any cleanups before dumping core
Rename coredump_exit_mm to coredump_task_exit and call it from do_exit
before PTRACE_EVENT_EXIT, and before any cleanup work for a task
happens.  This ensures that an accurate copy of the process can be
captured in the coredump as no cleanup for the process happens before
the coredump completes.  This also ensures that PTRACE_EVENT_EXIT
will not be visited by any thread until the coredump is complete.

Add a new flag PF_POSTCOREDUMP so that tasks that have passed through
coredump_task_exit can be recognized and ignored in zap_process.

Now that all of the coredumping happens before exit_mm remove code to
test for a coredump in progress from mm_release.

Replace "may_ptrace_stop()" with a simple test of "current->ptrace".
The other tests in may_ptrace_stop all concern avoiding stopping
during a coredump.  These tests are no longer necessary as it is now
guaranteed that fatal_signal_pending will be set if the code enters
ptrace_stop during a coredump.  The code in ptrace_stop is guaranteed
not to stop if fatal_signal_pending returns true.

Until this change "ptrace_event(PTRACE_EVENT_EXIT)" could call
ptrace_stop without fatal_signal_pending being true, as signals are
dequeued in get_signal before calling do_exit.  This is no longer
an issue as "ptrace_event(PTRACE_EVENT_EXIT)" is no longer reached
until after the coredump completes.

Link: https://lkml.kernel.org/r/874kaax26c.fsf@disp2133
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-10-06 11:28:39 -05:00
Liu Zixian
13db8c5047 mm/hugetlb: initialize hugetlb_usage in mm_init
After fork, the child process will get incorrect (2x) hugetlb_usage.  If
a process uses 5 2MB hugetlb pages in an anonymous mapping,

	HugetlbPages:	   10240 kB

and then forks, the child will show,

	HugetlbPages:	   20480 kB

The reason for double the amount is because hugetlb_usage will be copied
from the parent and then increased when we copy page tables from parent
to child.  Child will have 2x actual usage.

Fix this by adding hugetlb_count_init in mm_init.

Link: https://lkml.kernel.org/r/20210826071742.877-1-liuzixian4@huawei.com
Fixes: 5d317b2b65 ("mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status")
Signed-off-by: Liu Zixian <liuzixian4@huawei.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-08 18:45:53 -07:00
Linus Torvalds
2d338201d5 Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
 "147 patches, based on 7d2a07b769.

  Subsystems affected by this patch series: mm (memory-hotplug, rmap,
  ioremap, highmem, cleanups, secretmem, kfence, damon, and vmscan),
  alpha, percpu, procfs, misc, core-kernel, MAINTAINERS, lib,
  checkpatch, epoll, init, nilfs2, coredump, fork, pids, criu, kconfig,
  selftests, ipc, and scripts"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (94 commits)
  scripts: check_extable: fix typo in user error message
  mm/workingset: correct kernel-doc notations
  ipc: replace costly bailout check in sysvipc_find_ipc()
  selftests/memfd: remove unused variable
  Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH
  configs: remove the obsolete CONFIG_INPUT_POLLDEV
  prctl: allow to setup brk for et_dyn executables
  pid: cleanup the stale comment mentioning pidmap_init().
  kernel/fork.c: unexport get_{mm,task}_exe_file
  coredump: fix memleak in dump_vma_snapshot()
  fs/coredump.c: log if a core dump is aborted due to changed file permissions
  nilfs2: use refcount_dec_and_lock() to fix potential UAF
  nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group
  nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group
  nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group
  nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group
  nilfs2: fix NULL pointer in nilfs_##name##_attr_release
  nilfs2: fix memory leak in nilfs_sysfs_create_device_group
  trap: cleanup trap_init()
  init: move usermodehelper_enable() to populate_rootfs()
  ...
2021-09-08 12:55:35 -07:00
Christoph Hellwig
05da8113c9 kernel/fork.c: unexport get_{mm,task}_exe_file
Only used by core code and the tomoyo which can't be a module either.

Link: https://lkml.kernel.org/r/20210820095430.445242-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-08 11:50:28 -07:00
Linus Torvalds
49624efa65 Merge tag 'denywrite-for-5.15' of git://github.com/davidhildenbrand/linux
Pull MAP_DENYWRITE removal from David Hildenbrand:
 "Remove all in-tree usage of MAP_DENYWRITE from the kernel and remove
  VM_DENYWRITE.

  There are some (minor) user-visible changes:

   - We no longer deny write access to shared libaries loaded via legacy
     uselib(); this behavior matches modern user space e.g. dlopen().

   - We no longer deny write access to the elf interpreter after exec
     completed, treating it just like shared libraries (which it often
     is).

   - We always deny write access to the file linked via /proc/pid/exe:
     sys_prctl(PR_SET_MM_MAP/EXE_FILE) will fail if write access to the
     file cannot be denied, and write access to the file will remain
     denied until the link is effectivel gone (exec, termination,
     sys_prctl(PR_SET_MM_MAP/EXE_FILE)) -- just as if exec'ing the file.

  Cross-compiled for a bunch of architectures (alpha, microblaze, i386,
  s390x, ...) and verified via ltp that especially the relevant tests
  (i.e., creat07 and execve04) continue working as expected"

* tag 'denywrite-for-5.15' of git://github.com/davidhildenbrand/linux:
  fs: update documentation of get_write_access() and friends
  mm: ignore MAP_DENYWRITE in ksys_mmap_pgoff()
  mm: remove VM_DENYWRITE
  binfmt: remove in-tree usage of MAP_DENYWRITE
  kernel/fork: always deny write access to current MM exe_file
  kernel/fork: factor out replacing the current MM exe_file
  binfmt: don't use MAP_DENYWRITE when loading shared libraries via uselib()
2021-09-04 11:35:47 -07:00
David Hildenbrand
8d0920bde5 mm: remove VM_DENYWRITE
All in-tree users of MAP_DENYWRITE are gone. MAP_DENYWRITE cannot be
set from user space, so all users are gone; let's remove it.

Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
2021-09-03 18:42:01 +02:00
David Hildenbrand
fe69d560b5 kernel/fork: always deny write access to current MM exe_file
We want to remove VM_DENYWRITE only currently only used when mapping the
executable during exec. During exec, we already deny_write_access() the
executable, however, after exec completes the VMAs mapped
with VM_DENYWRITE effectively keeps write access denied via
deny_write_access().

Let's deny write access when setting or replacing the MM exe_file. With
this change, we can remove VM_DENYWRITE for mapping executables.

Make set_mm_exe_file() return an error in case deny_write_access()
fails; note that this should never happen, because exec code does a
deny_write_access() early and keeps write access denied when calling
set_mm_exe_file. However, it makes the code easier to read and makes
set_mm_exe_file() and replace_mm_exe_file() look more similar.

This represents a minor user space visible change:
sys_prctl(PR_SET_MM_MAP/EXE_FILE) can now fail if the file is already
opened writable. Also, after sys_prctl(PR_SET_MM_MAP/EXE_FILE) the file
cannot be opened writable. Note that we can already fail with -EACCES if
the file doesn't have execute permissions.

Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
2021-09-03 18:42:01 +02:00
David Hildenbrand
35d7bdc860 kernel/fork: factor out replacing the current MM exe_file
Let's factor the main logic out into replace_mm_exe_file(), such that
all mm->exe_file logic is contained in kernel/fork.c.

While at it, perform some simple cleanups that are possible now that
we're simplifying the individual functions.

Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
2021-09-03 18:42:01 +02:00
Linus Torvalds
9e9fb7655e Core:
- Enable memcg accounting for various networking objects.
 
 BPF:
 
  - Introduce bpf timers.
 
  - Add perf link and opaque bpf_cookie which the program can read
    out again, to be used in libbpf-based USDT library.
 
  - Add bpf_task_pt_regs() helper to access user space pt_regs
    in kprobes, to help user space stack unwinding.
 
  - Add support for UNIX sockets for BPF sockmap.
 
  - Extend BPF iterator support for UNIX domain sockets.
 
  - Allow BPF TCP congestion control progs and bpf iterators to call
    bpf_setsockopt(), e.g. to switch to another congestion control
    algorithm.
 
 Protocols:
 
  - Support IOAM Pre-allocated Trace with IPv6.
 
  - Support Management Component Transport Protocol.
 
  - bridge: multicast: add vlan support.
 
  - netfilter: add hooks for the SRv6 lightweight tunnel driver.
 
  - tcp:
     - enable mid-stream window clamping (by user space or BPF)
     - allow data-less, empty-cookie SYN with TFO_SERVER_COOKIE_NOT_REQD
     - more accurate DSACK processing for RACK-TLP
 
  - mptcp:
     - add full mesh path manager option
     - add partial support for MP_FAIL
     - improve use of backup subflows
     - optimize option processing
 
  - af_unix: add OOB notification support.
 
  - ipv6: add IFLA_INET6_RA_MTU to expose MTU value advertised by
          the router.
 
  - mac80211: Target Wake Time support in AP mode.
 
  - can: j1939: extend UAPI to notify about RX status.
 
 Driver APIs:
 
  - Add page frag support in page pool API.
 
  - Many improvements to the DSA (distributed switch) APIs.
 
  - ethtool: extend IRQ coalesce uAPI with timer reset modes.
 
  - devlink: control which auxiliary devices are created.
 
  - Support CAN PHYs via the generic PHY subsystem.
 
  - Proper cross-chip support for tag_8021q.
 
  - Allow TX forwarding for the software bridge data path to be
    offloaded to capable devices.
 
 Drivers:
 
  - veth: more flexible channels number configuration.
 
  - openvswitch: introduce per-cpu upcall dispatch.
 
  - Add internet mix (IMIX) mode to pktgen.
 
  - Transparently handle XDP operations in the bonding driver.
 
  - Add LiteETH network driver.
 
  - Renesas (ravb):
    - support Gigabit Ethernet IP
 
  - NXP Ethernet switch (sja1105)
    - fast aging support
    - support for "H" switch topologies
    - traffic termination for ports under VLAN-aware bridge
 
  - Intel 1G Ethernet
     - support getcrosststamp() with PCIe PTM (Precision Time
       Measurement) for better time sync
     - support Credit-Based Shaper (CBS) offload, enabling HW traffic
       prioritization and bandwidth reservation
 
  - Broadcom Ethernet (bnxt)
     - support pulse-per-second output
     - support larger Rx rings
 
  - Mellanox Ethernet (mlx5)
     - support ethtool RSS contexts and MQPRIO channel mode
     - support LAG offload with bridging
     - support devlink rate limit API
     - support packet sampling on tunnels
 
  - Huawei Ethernet (hns3):
     - basic devlink support
     - add extended IRQ coalescing support
     - report extended link state
 
  - Netronome Ethernet (nfp):
     - add conntrack offload support
 
  - Broadcom WiFi (brcmfmac):
     - add WPA3 Personal with FT to supported cipher suites
     - support 43752 SDIO device
 
  - Intel WiFi (iwlwifi):
     - support scanning hidden 6GHz networks
     - support for a new hardware family (Bz)
 
  - Xen pv driver:
     - harden netfront against malicious backends
 
  - Qualcomm mobile
     - ipa: refactor power management and enable automatic suspend
     - mhi: move MBIM to WWAN subsystem interfaces
 
 Refactor:
 
  - Ambient BPF run context and cgroup storage cleanup.
 
  - Compat rework for ndo_ioctl.
 
 Old code removal:
 
  - prism54 remove the obsoleted driver, deprecated by the p54 driver.
 
  - wan: remove sbni/granch driver.
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEE6jPA+I1ugmIBA4hXMUZtbf5SIrsFAmEukBYACgkQMUZtbf5S
 IrsyHA//TO8dw18NYts4n9LmlJT2naJ7yBUUSSXK/M+DtW0MQ9nnHhqzPm5uJdRl
 IgQTNJrW3dYzRwgqaWZqEwO1t5/FI+f87ND1Nsekg7x9tF66a6ov5WxU26TwwSba
 U+si/inQ/4chuQ+LxMQobqCDxaLE46I2dIoRl+YfndJ24DRzYSwAEYIPPbSdfyU+
 +/l+3s4GaxO4k/hLciPAiOniyxLoUNiGUTNh+2yqRBXelSRJRKVnl+V22ANFrxRW
 nTEiplfVKhlPU1e4iLuRtaxDDiePHhw9I3j/lMHhfeFU2P/gKJIvz4QpGV0CAZg2
 1VvDU32WEx1GQLXJbKm0KwoNRUq1QSjOyyFti+BO7ugGaYAR4gKhShOqlSYLzUtB
 tbtzQhSNLWOGqgmSJOztZb5kFDm2EdRSll5/lP2uyFlPkIsIp0QbscJVzNTnS74b
 Xz15ZOw41Z4TfWPEMWgfrx6Zkm7pPWkly+7WfUkPcHa1gftNz6tzXXxSXcXIBPdi
 yQ5JCzzxrM5573YHuk5YedwZpn6PiAt4A/muFGk9C6aXP60TQAOS/ppaUzZdnk4D
 NfOk9mj06WEULjYjPcKEuT3GGWE6kmjb8Pu0QZWKOchv7vr6oZly1EkVZqYlXELP
 AfhcrFeuufie8mqm0jdb4LnYaAnqyLzlb1J4Zxh9F+/IX7G3yoc=
 =JDGD
 -----END PGP SIGNATURE-----

Merge tag 'net-next-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Jakub Kicinski:
 "Core:

   - Enable memcg accounting for various networking objects.

  BPF:

   - Introduce bpf timers.

   - Add perf link and opaque bpf_cookie which the program can read out
     again, to be used in libbpf-based USDT library.

   - Add bpf_task_pt_regs() helper to access user space pt_regs in
     kprobes, to help user space stack unwinding.

   - Add support for UNIX sockets for BPF sockmap.

   - Extend BPF iterator support for UNIX domain sockets.

   - Allow BPF TCP congestion control progs and bpf iterators to call
     bpf_setsockopt(), e.g. to switch to another congestion control
     algorithm.

  Protocols:

   - Support IOAM Pre-allocated Trace with IPv6.

   - Support Management Component Transport Protocol.

   - bridge: multicast: add vlan support.

   - netfilter: add hooks for the SRv6 lightweight tunnel driver.

   - tcp:
       - enable mid-stream window clamping (by user space or BPF)
       - allow data-less, empty-cookie SYN with TFO_SERVER_COOKIE_NOT_REQD
       - more accurate DSACK processing for RACK-TLP

   - mptcp:
       - add full mesh path manager option
       - add partial support for MP_FAIL
       - improve use of backup subflows
       - optimize option processing

   - af_unix: add OOB notification support.

   - ipv6: add IFLA_INET6_RA_MTU to expose MTU value advertised by the
     router.

   - mac80211: Target Wake Time support in AP mode.

   - can: j1939: extend UAPI to notify about RX status.

  Driver APIs:

   - Add page frag support in page pool API.

   - Many improvements to the DSA (distributed switch) APIs.

   - ethtool: extend IRQ coalesce uAPI with timer reset modes.

   - devlink: control which auxiliary devices are created.

   - Support CAN PHYs via the generic PHY subsystem.

   - Proper cross-chip support for tag_8021q.

   - Allow TX forwarding for the software bridge data path to be
     offloaded to capable devices.

  Drivers:

   - veth: more flexible channels number configuration.

   - openvswitch: introduce per-cpu upcall dispatch.

   - Add internet mix (IMIX) mode to pktgen.

   - Transparently handle XDP operations in the bonding driver.

   - Add LiteETH network driver.

   - Renesas (ravb):
       - support Gigabit Ethernet IP

   - NXP Ethernet switch (sja1105):
       - fast aging support
       - support for "H" switch topologies
       - traffic termination for ports under VLAN-aware bridge

   - Intel 1G Ethernet
       - support getcrosststamp() with PCIe PTM (Precision Time
         Measurement) for better time sync
       - support Credit-Based Shaper (CBS) offload, enabling HW traffic
         prioritization and bandwidth reservation

   - Broadcom Ethernet (bnxt)
       - support pulse-per-second output
       - support larger Rx rings

   - Mellanox Ethernet (mlx5)
       - support ethtool RSS contexts and MQPRIO channel mode
       - support LAG offload with bridging
       - support devlink rate limit API
       - support packet sampling on tunnels

   - Huawei Ethernet (hns3):
       - basic devlink support
       - add extended IRQ coalescing support
       - report extended link state

   - Netronome Ethernet (nfp):
       - add conntrack offload support

   - Broadcom WiFi (brcmfmac):
       - add WPA3 Personal with FT to supported cipher suites
       - support 43752 SDIO device

   - Intel WiFi (iwlwifi):
       - support scanning hidden 6GHz networks
       - support for a new hardware family (Bz)

   - Xen pv driver:
       - harden netfront against malicious backends

   - Qualcomm mobile
       - ipa: refactor power management and enable automatic suspend
       - mhi: move MBIM to WWAN subsystem interfaces

  Refactor:

   - Ambient BPF run context and cgroup storage cleanup.

   - Compat rework for ndo_ioctl.

  Old code removal:

   - prism54 remove the obsoleted driver, deprecated by the p54 driver.

   - wan: remove sbni/granch driver"

* tag 'net-next-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1715 commits)
  net: Add depends on OF_NET for LiteX's LiteETH
  ipv6: seg6: remove duplicated include
  net: hns3: remove unnecessary spaces
  net: hns3: add some required spaces
  net: hns3: clean up a type mismatch warning
  net: hns3: refine function hns3_set_default_feature()
  ipv6: remove duplicated 'net/lwtunnel.h' include
  net: w5100: check return value after calling platform_get_resource()
  net/mlxbf_gige: Make use of devm_platform_ioremap_resourcexxx()
  net: mdio: mscc-miim: Make use of the helper function devm_platform_ioremap_resource()
  net: mdio-ipq4019: Make use of devm_platform_ioremap_resource()
  fou: remove sparse errors
  ipv4: fix endianness issue in inet_rtm_getroute_build_skb()
  octeontx2-af: Set proper errorcode for IPv4 checksum errors
  octeontx2-af: Fix static code analyzer reported issues
  octeontx2-af: Fix mailbox errors in nix_rss_flowkey_cfg
  octeontx2-af: Fix loop in free and unmap counter
  af_unix: fix potential NULL deref in unix_dgram_connect()
  dpaa2-eth: Replace strlcpy with strscpy
  octeontx2-af: Use NDC TX for transmit packet data
  ...
2021-08-31 16:43:06 -07:00
Linus Torvalds
5d3c0db459 Scheduler changes for v5.15 are:
- The biggest change in this cycle is scheduler support for asymmetric
   scheduling affinity, to support the execution of legacy 32-bit tasks on
   AArch32 systems that also have 64-bit-only CPUs.
 
   Architectures can fill in this functionality by defining their
   own task_cpu_possible_mask(p). When this is done, the scheduler will
   make sure the task will only be scheduled on CPUs that support it.
 
   (The actual arm64 specific changes are not part of this tree.)
 
   For other architectures there will be no change in functionality.
 
 - Add cgroup SCHED_IDLE support
 
 - Increase node-distance flexibility & delay determining it until a CPU
   is brought online. (This enables platforms where node distance isn't
   final until the CPU is only.)
 
 - Deadline scheduler enhancements & fixes
 
 - Misc fixes & cleanups.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAmEsrDgRHG1pbmdvQGtl
 cm5lbC5vcmcACgkQEnMQ0APhK1gMxBAAmzXPnDm1pDBBUaEwc+DynNGHNxZcBO5E
 CaNyfywp4GMA+OC3JzUgDg1B9uvKQRdBGtv6SZ8OcyhJMfmkEvjt5/wYUrcdtQVP
 TA2lt80/Is8LQMnvcz7X0gmsLt+fXWQTF8ik1KT4wsi/k03Xw8BH11zHct6sV2QN
 NNQ+7BEjqU1HA1UXJFiaoGtWF0gdh29VyE5dSzfAis79L0XUQadS512LJKin/AK0
 wYz8E+L7QIrjhfX9FQdOrR6da4TK6jAXyEY6a9dpaMHnFdtxuwhT4/BPtovNTeeY
 yxEZm3qSZbpghWHsMEa6Z4GIeLE6aNi3wcHt10fgdZDdotSRsNZuF6gi4A8nhRC+
 6wm+fCcFGEIBCL6eE/16Wms6YMdFfuiEAgtJGNy7GGyfH3/mS6u8eylXbLZncYXn
 DFHY+xUvmVZSzoPzcnYXEy4FB3kywNL7WBFxyhdXf5/EvWmmtHi4K3jVQ8jaqvhL
 MDk3NX9Hd0ariff3zUltWhMY5ouj6bIbBZmWWnD3s1xQT68VvE563cq0qH15dlnr
 j5M71eNRWvoOdZKzflgjRZzmdQtsZQ51tiMA6W6ZRfwYkHjb70qiia0r5GFf41X1
 MYelmcaA8+RjKrQ5etxzzDjoXl0xDXiZric6gRQHjG1Y1Zm2rVaoD+vkJGD5TQJ0
 2XTOGQgAxh4=
 =VdGE
 -----END PGP SIGNATURE-----

Merge tag 'sched-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - The biggest change in this cycle is scheduler support for asymmetric
   scheduling affinity, to support the execution of legacy 32-bit tasks
   on AArch32 systems that also have 64-bit-only CPUs.

   Architectures can fill in this functionality by defining their own
   task_cpu_possible_mask(p). When this is done, the scheduler will make
   sure the task will only be scheduled on CPUs that support it.

   (The actual arm64 specific changes are not part of this tree.)

   For other architectures there will be no change in functionality.

 - Add cgroup SCHED_IDLE support

 - Increase node-distance flexibility & delay determining it until a CPU
   is brought online. (This enables platforms where node distance isn't
   final until the CPU is only.)

 - Deadline scheduler enhancements & fixes

 - Misc fixes & cleanups.

* tag 'sched-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
  eventfd: Make signal recursion protection a task bit
  sched/fair: Mark tg_is_idle() an inline in the !CONFIG_FAIR_GROUP_SCHED case
  sched: Introduce dl_task_check_affinity() to check proposed affinity
  sched: Allow task CPU affinity to be restricted on asymmetric systems
  sched: Split the guts of sched_setaffinity() into a helper function
  sched: Introduce task_struct::user_cpus_ptr to track requested affinity
  sched: Reject CPU affinity changes based on task_cpu_possible_mask()
  cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq()
  cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus()
  cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1
  sched: Introduce task_cpu_possible_mask() to limit fallback rq selection
  sched: Cgroup SCHED_IDLE support
  sched/topology: Skip updating masks for non-online nodes
  sched: Replace deprecated CPU-hotplug functions.
  sched: Skip priority checks with SCHED_FLAG_KEEP_PARAMS
  sched: Fix UCLAMP_FLAG_IDLE setting
  sched/deadline: Fix missing clock update in migrate_task_rq_dl()
  sched/fair: Avoid a second scan of target in select_idle_cpu
  sched/fair: Use prev instead of new target as recent_used_cpu
  sched: Don't report SCHED_FLAG_SUGOV in sched_getattr()
  ...
2021-08-30 13:42:10 -07:00
Jakub Kicinski
97c78d0af5 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
drivers/net/wwan/mhi_wwan_mbim.c - drop the extra arg.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-26 17:57:57 -07:00