From: Muchun Song songmuchun@bytedance.com
stable inclusion from linux-4.19.148 commit d44a437826119e8307c3904c1e4f513095ea17cb
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[ 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 zhouchengming@bytedance.com Signed-off-by: Muchun Song songmuchun@bytedance.com Signed-off-by: Chengming Zhou zhouchengming@bytedance.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Acked-by: Masami Hiramatsu mhiramat@kernel.org Cc: "Naveen N . Rao" naveen.n.rao@linux.ibm.com Cc: Anil S Keshavamurthy anil.s.keshavamurthy@intel.com Cc: David S. Miller davem@davemloft.net Cc: Song Liu songliubraving@fb.com Cc: Steven Rostedt rostedt@goodmis.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200822030055.32383-1-songmuchun@bytedance.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- kernel/kprobes.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 1053330c5929..f231d3f335a3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2050,6 +2050,9 @@ 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)) { /* @@ -2232,7 +2235,10 @@ 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))) { @@ -2249,6 +2255,7 @@ static int kprobes_module_callback(struct notifier_block *nb, */ kill_kprobe(p); } + } } mutex_unlock(&kprobe_mutex); return NOTIFY_DONE;