[PATCH AUTOSEL 4.14 076/103] kprobes: Don't call BUG_ON() if there is a kprobe in use on free list

Sasha Levin
2019-11-08T11:57:49Z

From: Masami Hiramatsu <mhiramat@kernel.org>

[ Upstream commit cbdd96f5586151e48317d90a403941ec23f12660 ]

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>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/153666126882.21306.10738207224288507996.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/kprobes.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index f7a4602a76f98..d0fe20a5475f7 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -544,8 +544,14 @@ 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);
}
}
--
2.20.1