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From: Chao Yu <yuchao0@huawei.com>
To: <jaegeuk@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net
Subject: [f2fs-dev] [PATCH] f2fs: fix use-after-free issue
Date: Thu, 23 Jul 2020 18:28:06 +0800
Message-ID: <20200723102806.9662-1-yuchao0@huawei.com> (raw)

From: Li Guifu <bluce.liguifu@huawei.com>

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 relcating
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: Chao Yu <yuchao0@huawei.com>
---
 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 80cb7cd358f8..bf8bd64c8380 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1175,6 +1175,9 @@ static void f2fs_put_super(struct super_block *sb)
 	int i;
 	bool dropped;
 
+	/* unregister procfs/sysfs entries to avoid race case */
+	f2fs_unregister_sysfs(sbi);
+
 	f2fs_quota_off_umount(sb);
 
 	/* prevent remaining shrinker jobs */
@@ -1240,8 +1243,6 @@ 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);
-- 
2.26.2



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Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-23 10:28 Chao Yu [this message]
2020-07-23 15:26 ` Song Feng
2020-07-24  1:22   ` Chao Yu

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