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b2b5f36baf
[ Upstream commit d0aa72604fbd80c8aabb46eda00535ed35570f1f ]
Below race may cause NULL pointer dereference
P1 P2
dquot_free_inode quota_off
drop_dquot_ref
remove_dquot_ref
dquots = i_dquot(inode)
dquots = i_dquot(inode)
srcu_read_lock
dquots[cnt]) != NULL (1)
dquots[type] = NULL (2)
spin_lock(&dquots[cnt]->dq_dqb_lock) (3)
....
If dquot_free_inode(or other routines) checks inode's quota pointers (1)
before quota_off sets it to NULL(2) and use it (3) after that, NULL pointer
dereference will be triggered.
So let's fix it by using a temporary pointer to avoid this issue.
Signed-off-by: Wang Jianjian <wangjianjian3@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240202081852.2514092-1-wangjianjian3@huawei.com>
Stable-dep-of: 179b8c97ebf6 ("quota: Fix rcu annotations of inode dquot pointers")
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 8514899c1a4edf802f03c408db901063aa3f05a1)
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>