diff options
| author | Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2012-09-05 23:31:12 +0900 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2012-09-13 22:52:09 -0400 |
| commit | 4b036d54bf849a75d0103b33d92a53f89ecb9315 (patch) | |
| tree | a3951c4c6b585f15e02634993cde58986f848443 | |
| parent | a5e37863ab31d78faddff15675c89979792bc0bd (diff) | |
| download | linux-4b036d54bf849a75d0103b33d92a53f89ecb9315.tar.bz2 | |
kprobes/x86: Fix kprobes to collectly handle IP on ftrace
Current kprobe_ftrace_handler expects regs->ip == ip, but it is
incorrect (originally on x86-64). Actually, ftrace handler sets
regs->ip = ip + MCOUNT_INSN_SIZE.
kprobe_ftrace_handler must take care for that.
Link: http://lkml.kernel.org/r/20120905143112.10329.72069.stgit@localhost.localdomain
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| -rw-r--r-- | arch/x86/kernel/kprobes.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 47ae1023a93c..f49f60cca40d 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -1072,7 +1072,8 @@ void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, if (kprobe_running()) { kprobes_inc_nmissed_count(p); } else { - regs->ip += sizeof(kprobe_opcode_t); + /* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */ + regs->ip = ip + sizeof(kprobe_opcode_t); __this_cpu_write(current_kprobe, p); kcb->kprobe_status = KPROBE_HIT_ACTIVE; @@ -1080,13 +1081,15 @@ void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, p->pre_handler(p, regs); if (unlikely(p->post_handler)) { - /* Emulate singlestep as if there is a 5byte nop */ + /* + * Emulate singlestep (and also recover regs->ip) + * as if there is a 5byte nop + */ regs->ip = ip + MCOUNT_INSN_SIZE; kcb->kprobe_status = KPROBE_HIT_SSDONE; p->post_handler(p, regs, 0); } __this_cpu_write(current_kprobe, NULL); - regs->ip = ip; /* Recover for next callback */ } end: local_irq_restore(flags); |