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Subject[PATCH v2] kprobes: Rollback kprobe flags on failed arm_kprobe
Date
From: Chuang Wang <nashuiliang@gmail.com>

In aggrprobe scenes, if arm_kprobe() returns an error(e.g. livepatch and
kprobe are using the same function X), kprobe flags, while has been
modified to ~KPROBE_FLAG_DISABLED, is not rollled back.

Then, __disable_kprobe() will be failed in __unregister_kprobe_top(),
the kprobe list will be not removed from aggrprobe, memory leaks or
illegal pointers will be caused.

WARN disarm_kprobe:
Failed to disarm kprobe-ftrace at 00000000c729fdbc (-2)
RIP: 0010:disarm_kprobe+0xcc/0x110
Call Trace:
__disable_kprobe+0x78/0x90
__unregister_kprobe_top+0x13/0x1b0
? _cond_resched+0x15/0x30
unregister_kprobes+0x32/0x80
unregister_kprobe+0x1a/0x20

Illegal Pointers:
BUG: unable to handle kernel paging request at 0000000000656369
RIP: 0010:__get_valid_kprobe+0x69/0x90
Call Trace:
register_kprobe+0x30/0x60
__register_trace_kprobe.part.7+0x8b/0xc0
create_local_trace_kprobe+0xd2/0x130
perf_kprobe_init+0x83/0xd0

Fixes: 12310e343755 ("kprobes: Propagate error from arm_kprobe_ftrace()")
Cc: stable@vger.kernel.org
Signed-off-by: Jingren Zhou <zhoujingren@didiglobal.com>
Signed-off-by: Chuang Wang <nashuiliang@gmail.com>

---
v1->v2:
- Supplement commit information: fixline, Cc stable

kernel/kprobes.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index f214f8c088ed..c11c79e05a4c 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2422,8 +2422,11 @@ int enable_kprobe(struct kprobe *kp)
if (!kprobes_all_disarmed && kprobe_disabled(p)) {
p->flags &= ~KPROBE_FLAG_DISABLED;
ret = arm_kprobe(p);
- if (ret)
+ if (ret) {
p->flags |= KPROBE_FLAG_DISABLED;
+ if (p != kp)
+ kp->flags |= KPROBE_FLAG_DISABLED;
+ }
}
out:
mutex_unlock(&kprobe_mutex);
--
2.34.1
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