From 4029fed7d24cf306bb042b0bd8aa62f9d58ba79f Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Fri, 18 Sep 2020 21:20:21 -0700 Subject: kprobes: fix kill kprobe which has been marked as gone [ Upstream commit b0399092ccebd9feef68d4ceb8d6219a8c0caa05 ] If a kprobe is marked as gone, we should not kill it again. Otherwise, we can disarm the kprobe more than once. In that case, the statistics of kprobe_ftrace_enabled can unbalance which can lead to that kprobe do not work. Fixes: e8386a0cb22f ("kprobes: support probing module __exit function") Co-developed-by: Chengming Zhou Signed-off-by: Muchun Song Signed-off-by: Chengming Zhou Signed-off-by: Andrew Morton Acked-by: Masami Hiramatsu Cc: "Naveen N . Rao" Cc: Anil S Keshavamurthy Cc: David S. Miller Cc: Song Liu Cc: Steven Rostedt Cc: Link: https://lkml.kernel.org/r/20200822030055.32383-1-songmuchun@bytedance.com Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- kernel/kprobes.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 9aa2dbe6a456..6f63d78aceec 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2012,6 +2012,9 @@ static void kill_kprobe(struct kprobe *p) { struct kprobe *kp; + if (WARN_ON_ONCE(kprobe_gone(p))) + return; + p->flags |= KPROBE_FLAG_GONE; if (kprobe_aggrprobe(p)) { /* @@ -2154,7 +2157,10 @@ static int kprobes_module_callback(struct notifier_block *nb, mutex_lock(&kprobe_mutex); for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; - hlist_for_each_entry_rcu(p, head, hlist) + hlist_for_each_entry_rcu(p, head, hlist) { + if (kprobe_gone(p)) + continue; + if (within_module_init((unsigned long)p->addr, mod) || (checkcore && within_module_core((unsigned long)p->addr, mod))) { @@ -2165,6 +2171,7 @@ static int kprobes_module_callback(struct notifier_block *nb, */ kill_kprobe(p); } + } } mutex_unlock(&kprobe_mutex); return NOTIFY_DONE; -- cgit v1.2.3