Jan Kara
5b5f99bc91
BugLink: https://bugs.launchpad.net/bugs/2097575 [ Upstream commit 35ceae44742e1101f9d20adadbbbd92c05d7d659 ] When __fsnotify_recalc_mask() recomputes the mask on the watched object, the compiler can "optimize" the code to perform partial updates to the mask (including zeroing it at the beginning). Thus places checking the object mask without conn->lock such as fsnotify_object_watched() could see invalid states of the mask. Make sure the mask update is performed by one memory store using WRITE_ONCE(). Reported-by: syzbot+701037856c25b143f1ad@syzkaller.appspotmail.com Reported-by: Dmitry Vyukov <dvyukov@google.com> Link: https://lore.kernel.org/all/CACT4Y+Zk0ohwwwHSD63U2-PQ=UuamXczr1mKBD6xtj2dyYKBvA@mail.gmail.com Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Link: https://patch.msgid.link/20240717140623.27768-1-jack@suse.cz Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>