On 2022/01/04 22:26, Tetsuo Handa wrote: > On 2022/01/04 16:14, Christoph Hellwig wrote: >> On Mon, Jan 03, 2022 at 07:49:11PM +0900, Tetsuo Handa wrote: >>> syzbot is reporting hung task at blkdev_fallocate() [1], for it can take >>> minutes with mapping->invalidate_lock held. Since fallocate() has to accept >>> size > MAX_RW_COUNT bytes, we can't predict how long it will take. Thus, >>> mitigate this problem by using killable wait where possible. >> >> Well, but that also means we want all other users of the invalidate_lock >> to be killable, as fallocate vs fallocate synchronization is probably >> not the interesting case. > > Right. But being responsive to SIGKILL is generally preferable. > > syzbot (and other syzkaller based fuzzing) is reporting many hung task reports, > but many of such reports are simply overstressing. > > We can't use killable lock wait for release operation because it is a "void" > function. But we can use killable lock wait for majority of operations which > are not "void" functions. Use of killable lock wait where possible can improve > situation. > If there is no alternative, can we apply this patch?
