From: Yakov Lerner Date: Sun, 16 Mar 2008 08:21:21 +0000 (-0500) Subject: x86, kprobes: correct post-eip value in post_hander() X-Git-Tag: v2.6.26-rc1~1154^2~301 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=acb5b8a2dd0f901463d075382ea548935e679f4e;p=linux-2.6 x86, kprobes: correct post-eip value in post_hander() I was trying to get the address of instruction to be executed next after the kprobed instruction. But regs->eip in post_handler() contains value which is useless to the user. It's pre-corrected value. This value is difficult to use without access to resume_execution(), which is not exported anyway. I moved the invocation of post_handler() to *after* resume_execution(). Now regs->eip contains meaningful value in post_handler(). I do not think this change breaks any backward-compatibility. To make meaning of the old value, post_handler() would need access to resume_execution() which is not exported. I have difficulty to believe that previous, uncorrected, regs->eip can be meaningfully used in post_handler(). Signed-off-by: Yakov Lerner Acked-by: Ananth N Mavinakayanahalli Acked-by: Masami Hiramatsu Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 1e3de7db9a..cc8ae90103 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -858,15 +858,15 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs) if (!cur) return 0; + resume_execution(cur, regs, kcb); + regs->flags |= kcb->kprobe_saved_flags; + trace_hardirqs_fixup_flags(regs->flags); + if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { kcb->kprobe_status = KPROBE_HIT_SSDONE; cur->post_handler(cur, regs, 0); } - resume_execution(cur, regs, kcb); - regs->flags |= kcb->kprobe_saved_flags; - trace_hardirqs_fixup_flags(regs->flags); - /* Restore back the original saved kprobes variables and continue. */ if (kcb->kprobe_status == KPROBE_REENTER) { restore_previous_kprobe(kcb);