Waiman Long <long...@redhat.com> writes: > On 7/19/19 2:45 PM, Luis Henriques wrote: >> On Mon, May 20, 2019 at 04:59:12PM -0400, Waiman Long wrote: >>> The rwsem->owner contains not just the task structure pointer, it also >>> holds some flags for storing the current state of the rwsem. Some of >>> the flags may have to be atomically updated. To reflect the new reality, >>> the owner is now changed to an atomic_long_t type. >>> >>> New helper functions are added to properly separate out the task >>> structure pointer and the embedded flags. >> I started seeing KASAN use-after-free with current master, and a bisect >> showed me that this commit 94a9717b3c40 ("locking/rwsem: Make >> rwsem->owner an atomic_long_t") was the problem. Does it ring any >> bells? I can easily reproduce it with xfstests (generic/464). >> >> Cheers, >> -- >> Luís > > This patch shouldn't change the behavior of the rwsem code. The code > only access data within the rw_semaphore structures. I don't know why it > will cause a KASAN error. I will have to reproduce it and figure out > exactly which statement is doing the invalid access.
Yeah, screwing the bisection is something I've done in the past so I may have got the wrong commit. Another detail is that I was running xfstests against CephFS, I didn't tried with any other filesystem. I can try to reproduce with btrfs or xfs next week. Cheers, -- Luis