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Subject[PATCH -tip/urgent 2/2] [BUGFIX]kprobes: makes kprobes/enabled works correctly for optimized kprobes.
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Date
From: Wang Nan <wangnan0@huawei.com>

debugfs/kprobes/enabled doesn't work correctly on optimized kprobes.
Masami Hiramatsu has a test report on x86_64 platform:

https://lkml.org/lkml/2015/1/19/274

This patch forces it to unoptimize kprobe if kprobes_all_disarmed
is set. It also checks the flag in unregistering path for skipping
unneeded disarming process when kprobes globally disarmed.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
kernel/kprobes.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 9471710..fb995ef 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -869,7 +869,8 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt)
{
struct kprobe *_p;

- unoptimize_kprobe(p, false); /* Try to unoptimize */
+ /* Try to unoptimize */
+ unoptimize_kprobe(p, kprobes_all_disarmed);

if (!kprobe_queued(p)) {
arch_disarm_kprobe(p);
@@ -1571,7 +1572,13 @@ static struct kprobe *__disable_kprobe(struct kprobe *p)

/* Try to disarm and disable this/parent probe */
if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
- disarm_kprobe(orig_p, true);
+ /*
+ * If kprobes_all_disarmed is set, orig_p
+ * should have already been disarmed, so
+ * skip unneed disarming process.
+ */
+ if (!kprobes_all_disarmed)
+ disarm_kprobe(orig_p, true);
orig_p->flags |= KPROBE_FLAG_DISABLED;
}
}


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