[lvc-project] [PATCH 5.10 2/2] gfs2: Fix slab-use-after-free in gfs2_qd_dealloc

[Vasiliy Kovalev]

From: Juntong Deng <juntong.deng at outlook.com>

commit bdcb8aa434c6d36b5c215d02a9ef07551be25a37 upstream.

In gfs2_put_super(), whether withdrawn or not, the quota should
be cleaned up by gfs2_quota_cleanup().

Otherwise, struct gfs2_sbd will be freed before gfs2_qd_dealloc (rcu
callback) has run for all gfs2_quota_data objects, resulting in
use-after-free.

Also, gfs2_destroy_threads() and gfs2_quota_cleanup() is already called
by gfs2_make_fs_ro(), so in gfs2_put_super(), after calling
gfs2_make_fs_ro(), there is no need to call them again.

Reported-by: syzbot+29c47e9e51895928698c at syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=29c47e9e51895928698c
Signed-off-by: Juntong Deng <juntong.deng at outlook.com>
Signed-off-by: Andreas Gruenbacher <agruenba at redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Clayton Casciato <majortomtosourcecontrol at gmail.com>
(cherry picked from commit 7ad4e0a4f61c57c3ca291ee010a9d677d0199fba)
Signed-off-by: Vasiliy Kovalev <kovalev at altlinux.org>
---
 fs/gfs2/super.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index a9e3956a5b4698..d4399bec7b5b12 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -623,6 +623,8 @@ static void gfs2_put_super(struct super_block *sb)
 
 	if (!sb_rdonly(sb)) {
 		gfs2_make_fs_ro(sdp);
+	} else {
+		gfs2_quota_cleanup(sdp);
 	}
 	WARN_ON(gfs2_withdrawing(sdp));
 
-- 
2.33.8