On 04/04/2018 09:23 AM, Theodore Y. Ts'o wrote: > The commit 5149cbac4235: "locking/rwsem: Add DEBUG_RWSEMS to look for > lock/unlock emismatches" (newly added in this merge window) will cause > xfstests tests failures in generic/068 for all file systems. > > This is because the freeze and thaw ioctls, by design, are run in > different processes. It looks like the concern for why > CONFIG_DEBUG_RWSEMS was added is because read/write semaphores can > spin --- which if the case, we need to make sure that (a) the spinlock > code path is not used for the freeze/thaw ioctls, and (b) we don't > trigger the debug WARN_ON. > > Cheers, > The rwsem code has an up_read_non_owner() function for this kind of cross task lock/unlock. I think we should add the corresponding up_write_non_owner() for that. It is better to annotate those calls that have this issue rather than working around it. I will post a patch to address that later today. Cheers, Longman
