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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2014-04-17 17:16:51 +0900
committerIngo Molnar <mingo@kernel.org>2014-04-24 10:02:55 +0200
commit6a5022a56ac37da7bffece043331a101ed0040b1 (patch)
treeefe8e5aadff08546e7a2836bf992961601a2d213
parent4d0fa8a0f01272d4de33704f20303dcecdb55df1 (diff)
kprobes/x86: Allow to handle reentered kprobe on single-stepping
Since the NMI handlers(e.g. perf) can interrupt in the single stepping (or preparing the single stepping, do_debug etc.), we should consider a kprobe is hit in the NMI handler. Even in that case, the kprobe is allowed to be reentered as same as the kprobes hit in kprobe handlers (KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE). The real issue will happen when a kprobe hit while another reentered kprobe is processing (KPROBE_REENTER), because we already consumed a saved-area for the previous kprobe. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Jonathan Lebon <jlebon@redhat.com> Link: http://lkml.kernel.org/r/20140417081651.26341.10593.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/kernel/kprobes/core.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 61b17dc2c277..da7bdaa3ce15 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -531,10 +531,11 @@ reenter_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb
switch (kcb->kprobe_status) {
case KPROBE_HIT_SSDONE:
case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SS:
kprobes_inc_nmissed_count(p);
setup_singlestep(p, regs, kcb, 1);
break;
- case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
/* A probe has been hit in the codepath leading up to, or just
* after, single-stepping of a probed instruction. This entire
* codepath should strictly reside in .kprobes.text section.