From 97236ad5a68c6b7603cea2ad01c588887e5cb961 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Sun, 4 Dec 2022 13:02:39 +0100 Subject: gfs2: Avoid dequeuing GL_ASYNC glock holders twice When a locking request fails, the associated glock holder is automatically dequeued from the list of active and waiting holders. For GL_ASYNC locking requests, this will obviously happen asynchronously and it can race with attempts to cancel that locking request via gfs2_glock_dq(). Therefore, don't forget to check if a locking request has already been dequeued in gfs2_glock_dq(). Signed-off-by: Andreas Gruenbacher --- fs/gfs2/glock.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'fs/gfs2') diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 1a6c1eb7bd6b..0f5c5c12d8c6 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1707,6 +1707,13 @@ void gfs2_glock_dq(struct gfs2_holder *gh) struct gfs2_glock *gl = gh->gh_gl; spin_lock(&gl->gl_lockref.lock); + if (!gfs2_holder_queued(gh)) { + /* + * May have already been dequeued because the locking request + * was GL_ASYNC and it has failed in the meantime. + */ + goto out; + } if (list_is_first(&gh->gh_list, &gl->gl_holders) && !test_bit(HIF_HOLDER, &gh->gh_iflags)) { spin_unlock(&gl->gl_lockref.lock); @@ -1716,6 +1723,7 @@ void gfs2_glock_dq(struct gfs2_holder *gh) } __gfs2_glock_dq(gh); +out: spin_unlock(&gl->gl_lockref.lock); } -- cgit v1.2.3