Hi Chuang,
On Tue, 14 Jun 2022 17:06:33 +0800 Chuang W nashuiliang@gmail.com wrote:
In a scenario where livepatch and aggrprobe coexist, if arm_kprobe() returns an error, ap.post_handler, while has been modified to p.post_handler, is not rolled back.
Would you mean 'coexist' on the same function?
When ap.post_handler is not NULL (not rolled back), the caller (e.g. register_kprobe/enable_kprobe) of arm_kprobe_ftrace() will always fail.
It seems this explanation and the actual code does not match. Can you tell me what actually you observed?
Thank you,
Fixes: 12310e343755 ("kprobes: Propagate error from arm_kprobe_ftrace()") Signed-off-by: Chuang W nashuiliang@gmail.com Cc: stable@vger.kernel.org
kernel/kprobes.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index f214f8c088ed..0610b02a3a05 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1300,6 +1300,7 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) { int ret = 0; struct kprobe *ap = orig_p;
- kprobe_post_handler_t old_post_handler = NULL;
cpus_read_lock(); @@ -1351,6 +1352,9 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) /* Copy the insn slot of 'p' to 'ap'. */ copy_kprobe(ap, p);
- /* save the old post_handler */
- old_post_handler = ap->post_handler; ret = add_new_kprobe(ap, p);
out: @@ -1365,6 +1369,7 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) ret = arm_kprobe(ap); if (ret) { ap->flags |= KPROBE_FLAG_DISABLED;
ap->post_handler = old_post_handler; list_del_rcu(&p->list); synchronize_rcu(); }-- 2.34.1