On Tue, Aug 16, 2022 at 02:58:10AM +0900, Hector Martin wrote: > This has been broken since the dawn of time, and it was incompletely > fixed by 346c09f80459, which added the necessary barriers in the work > execution path but failed to account for the missing barrier in the > test_and_set_bit() failure case. Fix it by switching to > atomic_long_fetch_or(), which does have unconditional barrier semantics > regardless of whether the bit was already set or not (this is actually > just test_and_set_bit() minus the early exit path). ... Oh, tricky one and yeah you're absolutely right that it makes no sense to not guarantee barrier semantics when already pending. I didn't even know test_and_set_bit() wasn't a barrier when it failed. Thanks a lot for hunting down and fixing this. Applied to wq/for-6.0-fixes. Thanks. -- tejun
