On Wed, Jan 23, 2019 at 09:44:12AM +0900, Tetsuo Handa wrote: > Daniel Jordan wrote: > > On Sat, Jan 19, 2019 at 11:41:22AM +0900, Tetsuo Handa wrote: > > > On 2019/01/19 4:48, Daniel Jordan wrote: > > > > On Sat, Jan 19, 2019 at 02:04:58AM +0900, Tetsuo Handa wrote: > > > > __queue_work has a sanity check already for work, but using list_empty. > > > > Seems > > > > slightly better to be consistent? > > > > > > > > > > list_empty() won't work, for "struct work_struct" is embedded into a > > > struct > > > which is allocated by kzalloc(). > > > > Please check list_empty's definition again, it compares the address of the > > node > > to its next pointer, so it should work for a zeroed node. I'll reiterate > > that > > it seems slightly better to be consistent in "is work_struct initialized?" > > checks, but it's not a big deal and I'm fine either way. > > You are talking about > > if (WARN_ON(!list_empty(&work->entry))) { > spin_unlock(&pwq->pool->lock); > return; > } > > part in __queue_work(), aren't you? But since flush_work() is used for > waiting for > a work to complete, that work can be either queued state (list_empty() == > false) or > not queued state (list_empty() == true). Thus, I don't think that > flush_work() can > use list_empty() for checking whether that work was initialized. > > > > [PATCH v2] workqueue: Try to catch flush_work() without INIT_WORK(). > > 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-ker...@i-love.sakura.ne.jp>
Applied to wq/for-5.0. Thanks. -- tejun