On Tue, Aug 16, 2022 at 03:28:50PM +0900, Hector Martin wrote: > > This is the same reason I argued queue_work() itself needs to have a > similar guarantee, even when it doesn't queue work (and I updated the > doc to match). If test_and_set_bit() is used in this kind of context > often in the kernel, clearly the current implementation/doc clashes with > that. Kernel code all over the place rely on the fact that test_and_set_bit provides a memory barrier. So this bug that you've discovered is not at all isolated to the workqeueue system. It'll break the kernel in lots of places in exactly the same way. > As I said, I don't have any particular beef in this fight, but this is > horribly broken on M1/2 right now, so I'll send a patch to change the > bitops instead and you all can fight it out over which way is correct :) Please do. Thanks, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
