From: Xia Fukun xiafukun@huawei.com
stable inclusion from stable-v4.19.267 commit 93d9cef55f8fe463e3b9f6c73c7a32619222c657 category: bugfix bugzilla: 187828, https://gitee.com/openeuler/kernel/issues/I63UEU CVE: NA
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[ Upstream commit a382f8fee42ca10c9bfce0d2352d4153f931f5dc ]
These are indeed "should not happen" situations, but it turns out recent changes made the 'task_is_stopped_or_trace()' case trigger (fix for that exists, is pending more testing), and the BUG_ON() makes it unnecessarily hard to actually debug for no good reason.
It's been that way for a long time, but let's make it clear: BUG_ON() is not good for debugging, and should never be used in situations where you could just say "this shouldn't happen, but we can continue".
Use WARN_ON_ONCE() instead to make sure it gets logged, and then just continue running. Instead of making the system basically unusuable because you crashed the machine while potentially holding some very core locks (eg this function is commonly called while holding 'tasklist_lock' for writing).
Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Xia Fukun xiafukun@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- kernel/signal.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c index d8f810e9fc34..69b9d8bff5a8 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1831,12 +1831,12 @@ bool do_notify_parent(struct task_struct *tsk, int sig) bool autoreap = false; u64 utime, stime;
- BUG_ON(sig == -1); + WARN_ON_ONCE(sig == -1);
- /* do_notify_parent_cldstop should have been called instead. */ - BUG_ON(task_is_stopped_or_traced(tsk)); + /* do_notify_parent_cldstop should have been called instead. */ + WARN_ON_ONCE(task_is_stopped_or_traced(tsk));
- BUG_ON(!tsk->ptrace && + WARN_ON_ONCE(!tsk->ptrace && (tsk->group_leader != tsk || !thread_group_empty(tsk)));
if (sig != SIGCHLD) {