From 1d47922b98046b8070a77347fb883a6523792803 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Sun, 14 Dec 2025 16:47:34 +0000 Subject: [PATCH] gfs2: Fix slab-use-after-free in qd_put [ Upstream commit 22150a7d401d9e9169b9b68e05bed95f7f49bf69 ] Commit a475c5dd16e5 ("gfs2: Free quota data objects synchronously") started freeing quota data objects during filesystem shutdown instead of putting them back onto the LRU list, but it failed to remove these objects from the LRU list, causing LRU list corruption. This caused use-after-free when the shrinker (gfs2_qd_shrink_scan) tried to access already-freed objects on the LRU list. Fix this by removing qd objects from the LRU list before freeing them in qd_put(). Initial fix from Deepanshu Kartikey . Fixes: a475c5dd16e5 ("gfs2: Free quota data objects synchronously") Reported-by: syzbot+046b605f01802054bff0@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=046b605f01802054bff0 Signed-off-by: Andreas Gruenbacher Signed-off-by: Sasha Levin --- fs/gfs2/quota.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c index f2df01f801b8..898fc3937b44 100644 --- a/fs/gfs2/quota.c +++ b/fs/gfs2/quota.c @@ -334,6 +334,7 @@ static void qd_put(struct gfs2_quota_data *qd) lockref_mark_dead(&qd->qd_lockref); spin_unlock(&qd->qd_lockref.lock); + list_lru_del_obj(&gfs2_qd_lru, &qd->qd_lru); gfs2_qd_dispose(qd); return; }