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kprobes: treewide: Replace arch_deref_entry_point() with dereference_symbol_descriptor()

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~15 years ago kprobes grew the 'arch_deref_entry_point()' __weak function:

  3d7e33825d: ("jprobes: make jprobes a little safer for users")

But this is just open-coded dereference_symbol_descriptor() in essence, and
its obscure nature was causing bugs.

Just use the real thing and remove arch_deref_entry_point().

Link: https://lkml.kernel.org/r/163163043630.489837.7924988885652708696.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2021-09-14 23:40:36 +09:00 • committed by Steven Rostedt (VMware)
parent a7fe237845
commit f2ec8d9a3b
5 changed files with 3 additions and 24 deletions
Download patch file Download diff file Expand all files Collapse all files

5
arch/ia64/kernel/kprobes.c
View file

@ -891,11 +891,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
return ret; return ret;
} }
unsigned long arch_deref_entry_point(void *entry)
{
return ((struct fnptr *)entry)->ip;
}
static struct kprobe trampoline_p = { static struct kprobe trampoline_p = {
.pre_handler = trampoline_probe_handler .pre_handler = trampoline_probe_handler
}; };

11
arch/powerpc/kernel/kprobes.c
View file

@ -542,17 +542,6 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
} }
NOKPROBE_SYMBOL(kprobe_fault_handler); NOKPROBE_SYMBOL(kprobe_fault_handler);
unsigned long arch_deref_entry_point(void *entry)
{
#ifdef PPC64_ELF_ABI_v1
if (!kernel_text_address((unsigned long)entry))
return ppc_global_function_entry(entry);
else
#endif
return (unsigned long)entry;
}
NOKPROBE_SYMBOL(arch_deref_entry_point);
static struct kprobe trampoline_p = { static struct kprobe trampoline_p = {
.addr = (kprobe_opcode_t *) &kretprobe_trampoline, .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
.pre_handler = trampoline_probe_handler .pre_handler = trampoline_probe_handler

1
include/linux/kprobes.h
View file

@ -381,7 +381,6 @@ int register_kprobe(struct kprobe *p);
void unregister_kprobe(struct kprobe *p); void unregister_kprobe(struct kprobe *p);
int register_kprobes(struct kprobe **kps, int num); int register_kprobes(struct kprobe **kps, int num);
void unregister_kprobes(struct kprobe **kps, int num); void unregister_kprobes(struct kprobe **kps, int num);
unsigned long arch_deref_entry_point(void *);
int register_kretprobe(struct kretprobe *rp); int register_kretprobe(struct kretprobe *rp);
void unregister_kretprobe(struct kretprobe *rp); void unregister_kretprobe(struct kretprobe *rp);

7
kernel/kprobes.c
View file

@ -1861,11 +1861,6 @@ static struct notifier_block kprobe_exceptions_nb = {
.priority = 0x7fffffff /* we need to be notified first */ .priority = 0x7fffffff /* we need to be notified first */
}; };
unsigned long __weak arch_deref_entry_point(void *entry)
{
return (unsigned long)entry;
}
#ifdef CONFIG_KRETPROBES #ifdef CONFIG_KRETPROBES
unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
@ -2327,7 +2322,7 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
int ret; int ret;
for (iter = start; iter < end; iter++) { for (iter = start; iter < end; iter++) {
entry = arch_deref_entry_point((void *)*iter); entry = (unsigned long)dereference_symbol_descriptor((void *)*iter);
ret = kprobe_add_ksym_blacklist(entry); ret = kprobe_add_ksym_blacklist(entry);
if (ret == -EINVAL) if (ret == -EINVAL)
continue; continue;

3
lib/error-inject.c
View file

@ -8,6 +8,7 @@
#include <linux/mutex.h> #include <linux/mutex.h>
#include <linux/list.h> #include <linux/list.h>
#include <linux/slab.h> #include <linux/slab.h>
#include <asm/sections.h>
/* Whitelist of symbols that can be overridden for error injection. */ /* Whitelist of symbols that can be overridden for error injection. */
static LIST_HEAD(error_injection_list); static LIST_HEAD(error_injection_list);
@ -64,7 +65,7 @@ static void populate_error_injection_list(struct error_injection_entry *start,
mutex_lock(&ei_mutex); mutex_lock(&ei_mutex);
for (iter = start; iter < end; iter++) { for (iter = start; iter < end; iter++) {
entry = arch_deref_entry_point((void *)iter->addr); entry = (unsigned long)dereference_symbol_descriptor((void *)iter->addr);
if (!kernel_text_address(entry) || if (!kernel_text_address(entry) ||
!kallsyms_lookup_size_offset(entry, &size, &offset)) { !kallsyms_lookup_size_offset(entry, &size, &offset)) {