| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 047/214] f2fs: fix use-after-free issue | Date | Tue, 1 Sep 2020 17:08:47 +0200 |
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From: Li Guifu <bluce.liguifu@huawei.com>
[ Upstream commit 99c787cfd2bd04926f1f553b30bd7dcea2caaba1 ]
During umount, f2fs_put_super() unregisters procfs entries after f2fs_destroy_segment_manager(), it may cause use-after-free issue when umount races with procfs accessing, fix it by relocating f2fs_unregister_sysfs().
[Chao Yu: change commit title/message a bit]
Signed-off-by: Li Guifu <bluce.liguifu@huawei.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- fs/f2fs/super.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index f4b882ee48ddf..fa461db696e79 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -1075,6 +1075,9 @@ static void f2fs_put_super(struct super_block *sb) int i; bool dropped; + /* unregister procfs/sysfs entries in advance to avoid race case */ + f2fs_unregister_sysfs(sbi); + f2fs_quota_off_umount(sb); /* prevent remaining shrinker jobs */ @@ -1138,8 +1141,6 @@ static void f2fs_put_super(struct super_block *sb) kvfree(sbi->ckpt); - f2fs_unregister_sysfs(sbi); - sb->s_fs_info = NULL; if (sbi->s_chksum_driver) crypto_free_shash(sbi->s_chksum_driver); -- 2.25.1
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