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| author | Zhang, Yanmin <yanmin.zhang@intel.com> | 2005-09-30 11:59:20 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-30 12:41:20 -0700 |
| commit | 2dd960d66bc12b6b206e63104636514e5da0ddb7 (patch) | |
| tree | 07fc074809ad2028891201f10b0279d3280da5e6 /arch | |
| parent | 32e7a04faa29f50f65e06d43a9029bb607743e76 (diff) | |
| download | op-kernel-dev-2dd960d66bc12b6b206e63104636514e5da0ddb7.zip op-kernel-dev-2dd960d66bc12b6b206e63104636514e5da0ddb7.tar.gz | |
[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')
| -rw-r--r-- | arch/x86_64/kernel/kprobes.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c index df08c43..76a28b0 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) |
