[PATCH -tip v2 5/5] kprobes: Don't call BUG_ON if there is a kprobe in use on free list

[Masami Hiramatsu <mhiramat@kernel.org>]

Instead of calling BUG_ON, if we find a kprobe in use on free kprobe
list, just remove it from the list and keep it on kprobe hash list
as same as other in-use kprobes.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 Changes in v2:
  - Use WARN_ON_ONCE() for unusual case.
---
 kernel/kprobes.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 63c342e5e6c3..90e98e233647 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -546,8 +546,14 @@ static void do_free_cleaned_kprobes(void)
 	struct optimized_kprobe *op, *tmp;
 
 	list_for_each_entry_safe(op, tmp, &freeing_list, list) {
-		BUG_ON(!kprobe_unused(&op->kp));
 		list_del_init(&op->list);
+		if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) {
+			/*
+			 * This must not happen, but if there is a kprobe
+			 * still in use, keep it on kprobes hash list.
+			 */
+			continue;
+		}
 		free_aggr_kprobe(&op->kp);
 	}
 }