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authorZhang, Yanmin <yanmin.zhang@intel.com>2005-09-30 11:59:20 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-30 12:41:20 -0700
commit2dd960d66bc12b6b206e63104636514e5da0ddb7 (patch)
tree07fc074809ad2028891201f10b0279d3280da5e6 /arch/x86_64/kernel
parent32e7a04faa29f50f65e06d43a9029bb607743e76 (diff)
[PATCH] utilization of kprobe_mutex is incorrect on x86_64
The up()/down() orders are incorrect in arch/x86_64/kprobes.c file. kprobe_mutext is used to protect the free kprobe instruction slot list. arch_prepare_kprobe applies for a slot from the free list, and arch_remove_kprobe returns a slot to the free list. The incorrect up()/down() orders to operate on kprobe_mutex fail to protect the free list. If 2 threads try to get/return kprobe instruction slot at the same time, the free slot list might be broken, or a free slot might be applied by 2 threads. Signed-off-by: Zhang Yanmin <Yanmin.zhang@intel.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/x86_64/kernel')
-rw-r--r--arch/x86_64/kernel/kprobes.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c
index df08c43276a..76a28b007be 100644
--- a/arch/x86_64/kernel/kprobes.c
+++ b/arch/x86_64/kernel/kprobes.c
@@ -77,9 +77,9 @@ static inline int is_IF_modifier(kprobe_opcode_t *insn)
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
/* insn: must be on special executable page on x86_64. */
- up(&kprobe_mutex);
- p->ainsn.insn = get_insn_slot();
down(&kprobe_mutex);
+ p->ainsn.insn = get_insn_slot();
+ up(&kprobe_mutex);
if (!p->ainsn.insn) {
return -ENOMEM;
}
@@ -231,9 +231,9 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
- up(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn);
down(&kprobe_mutex);
+ free_insn_slot(p->ainsn.insn);
+ up(&kprobe_mutex);
}
static inline void save_previous_kprobe(void)