| Message ID | 1420461140-27153-1-git-send-email-wangnan0@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
(2015/01/05 21:32), Wang Nan wrote: > Original code failed to disarm the probed instruction after > > echo 0 > /sys/kernel/debug/kprobes/enabled > > if OPTPROBE is enabled. > > This is caused by a piece of logically inconsistent code: > > unoptimize_kprobe(p, false); > if (!kprobe_queued(p)) { > ... > } > > unoptimize_kprobe() with 'force' == false queues p onto > unoptimizing_list, so following kprobe_queued() check always fail unless > another core schedules optimizer and does the unoptimization very soon. > This logic causes arch_disarm_kprobe() failed to get execute, lefts a > breakpoint at the probed address, instead of restoring it. No, the root cause of this failure comes from the lack of checking kprobes_all_disarmed in unoptimized_kprobe(). It should check the flag and return soon if it is set. So, I Nak this patch. > > This patch uses force unoptimize instead. > > Signed-off-by: Wang Nan <wangnan0@huawei.com> > --- > kernel/kprobes.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index b185464..9fbe0c3 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -869,7 +869,7 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt) > { > struct kprobe *_p; > > - unoptimize_kprobe(p, false); /* Try to unoptimize */ > + unoptimize_kprobe(p, true); /* Try to unoptimize */ > > if (!kprobe_queued(p)) { > arch_disarm_kprobe(p); >
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index b185464..9fbe0c3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -869,7 +869,7 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt) { struct kprobe *_p; - unoptimize_kprobe(p, false); /* Try to unoptimize */ + unoptimize_kprobe(p, true); /* Try to unoptimize */ if (!kprobe_queued(p)) { arch_disarm_kprobe(p);
Original code failed to disarm the probed instruction after echo 0 > /sys/kernel/debug/kprobes/enabled if OPTPROBE is enabled. This is caused by a piece of logically inconsistent code: unoptimize_kprobe(p, false); if (!kprobe_queued(p)) { ... } unoptimize_kprobe() with 'force' == false queues p onto unoptimizing_list, so following kprobe_queued() check always fail unless another core schedules optimizer and does the unoptimization very soon. This logic causes arch_disarm_kprobe() failed to get execute, lefts a breakpoint at the probed address, instead of restoring it. This patch uses force unoptimize instead. Signed-off-by: Wang Nan <wangnan0@huawei.com> --- kernel/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)