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srcu: Debug NMI safety even on archs that don't require it

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Currently the NMI safety debugging is only performed on architectures
that don't support NMI-safe this_cpu_inc().

Reorder the code so that other architectures like x86 also detect bad
uses.

[ paulmck: Apply kernel test robot, Stephen Rothwell, and Zqiang feedback. ]

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Frederic Weisbecker 2022-10-13 19:22:44 +02:00 • committed by Paul E. McKenney
parent ae3c070616
commit e29a4915db
3 changed files with 34 additions and 31 deletions
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36
include/linux/srcu.h
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@ -65,14 +65,14 @@ unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp);
bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie);
#ifdef CONFIG_NEED_SRCU_NMI_SAFE
int __srcu_read_lock_nmisafe(struct srcu_struct *ssp, bool chknmisafe) __acquires(ssp);
void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx, bool chknmisafe) __releases(ssp);
int __srcu_read_lock_nmisafe(struct srcu_struct *ssp) __acquires(ssp);
void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx) __releases(ssp);
#else
static inline int __srcu_read_lock_nmisafe(struct srcu_struct *ssp, bool chknmisafe)
static inline int __srcu_read_lock_nmisafe(struct srcu_struct *ssp)
{
return __srcu_read_lock(ssp);
}
static inline void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx, bool chknmisafe)
static inline void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx)
{
__srcu_read_unlock(ssp, idx);
}
@ -118,6 +118,18 @@ static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
#define SRCU_NMI_UNKNOWN 0x0
#define SRCU_NMI_UNSAFE 0x1
#define SRCU_NMI_SAFE 0x2
#if defined(CONFIG_PROVE_RCU) && defined(CONFIG_TREE_SRCU)
void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe);
#else
static inline void srcu_check_nmi_safety(struct srcu_struct *ssp,
bool nmi_safe) { }
#endif
/**
* srcu_dereference_check - fetch SRCU-protected pointer for later dereferencing
* @p: the pointer to fetch and protect for later dereferencing
@ -175,6 +187,7 @@ static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp)
{
int retval;
srcu_check_nmi_safety(ssp, false);
retval = __srcu_read_lock(ssp);
rcu_lock_acquire(&(ssp)->dep_map);
return retval;
@ -191,10 +204,8 @@ static inline int srcu_read_lock_nmisafe(struct srcu_struct *ssp) __acquires(ssp
{
int retval;
if (IS_ENABLED(CONFIG_NEED_SRCU_NMI_SAFE))
retval = __srcu_read_lock_nmisafe(ssp, true);
else
retval = __srcu_read_lock(ssp);
srcu_check_nmi_safety(ssp, true);
retval = __srcu_read_lock_nmisafe(ssp);
rcu_lock_acquire(&(ssp)->dep_map);
return retval;
}
@ -205,6 +216,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp) __acquires(ssp)
{
int retval;
srcu_check_nmi_safety(ssp, false);
retval = __srcu_read_lock(ssp);
return retval;
}
@ -220,6 +232,7 @@ static inline void srcu_read_unlock(struct srcu_struct *ssp, int idx)
__releases(ssp)
{
WARN_ON_ONCE(idx & ~0x1);
srcu_check_nmi_safety(ssp, false);
rcu_lock_release(&(ssp)->dep_map);
__srcu_read_unlock(ssp, idx);
}
@ -235,17 +248,16 @@ static inline void srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx)
__releases(ssp)
{
WARN_ON_ONCE(idx & ~0x1);
srcu_check_nmi_safety(ssp, true);
rcu_lock_release(&(ssp)->dep_map);
if (IS_ENABLED(CONFIG_NEED_SRCU_NMI_SAFE))
__srcu_read_unlock_nmisafe(ssp, idx, true);
else
__srcu_read_unlock(ssp, idx);
__srcu_read_unlock_nmisafe(ssp, idx);
}
/* Used by tracing, cannot be traced and cannot call lockdep. */
static inline notrace void
srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp)
{
srcu_check_nmi_safety(ssp, false);
__srcu_read_unlock(ssp, idx);
}