From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> commit 4d43d395fed124631ca02356c711facb90185175 upstream. syzbot found a flush_work() caller who forgot to call INIT_WORK() because that work_struct was allocated by kzalloc() [1]. But the message INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. by lock_map_acquire() is failing to tell that INIT_WORK() is missing. Since flush_work() without INIT_WORK() is a bug, and INIT_WORK() should set ->func field to non-zero, let's warn if ->func field is zero. [1] https://syzkaller.appspot.com/bug?id=a5954455fcfa51c29ca2ab55b203076337e1c770 Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/workqueue.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2908,6 +2908,9 @@ static bool __flush_work(struct work_str if (WARN_ON(!wq_online)) return false; + if (WARN_ON(!work->func)) + return false; + if (!from_cancel) { lock_map_acquire(&work->lockdep_map); lock_map_release(&work->lockdep_map);
