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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>,
	syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com,
	Viacheslav Dubeyko <slava@dubeyko.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Shuah Khan <skhan@linuxfoundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 13/17] hfs: add lock nesting notation to hfs_find_init
Date: Thu, 29 Jul 2021 15:54:14 +0200	[thread overview]
Message-ID: <20210729135137.678656929@linuxfoundation.org> (raw)
In-Reply-To: <20210729135137.260993951@linuxfoundation.org>

From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>

[ Upstream commit b3b2177a2d795e35dc11597b2609eb1e7e57e570 ]

Syzbot reports a possible recursive lock in [1].

This happens due to missing lock nesting information.  From the logs, we
see that a call to hfs_fill_super is made to mount the hfs filesystem.
While searching for the root inode, the lock on the catalog btree is
grabbed.  Then, when the parent of the root isn't found, a call to
__hfs_bnode_create is made to create the parent of the root.  This
eventually leads to a call to hfs_ext_read_extent which grabs a lock on
the extents btree.

Since the order of locking is catalog btree -> extents btree, this lock
hierarchy does not lead to a deadlock.

To tell lockdep that this locking is safe, we add nesting notation to
distinguish between catalog btrees, extents btrees, and attributes
btrees (for HFS+).  This has already been done in hfsplus.

Link: https://syzkaller.appspot.com/bug?id=f007ef1d7a31a469e3be7aeb0fde0769b18585db [1]
Link: https://lkml.kernel.org/r/20210701030756.58760-4-desmondcheongzx@gmail.com
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reported-by: syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com
Tested-by: syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfs/bfind.c | 14 +++++++++++++-
 fs/hfs/btree.h |  7 +++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/fs/hfs/bfind.c b/fs/hfs/bfind.c
index 4af318fbda77..ef9498a6e88a 100644
--- a/fs/hfs/bfind.c
+++ b/fs/hfs/bfind.c
@@ -25,7 +25,19 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
 	fd->key = ptr + tree->max_key_len + 2;
 	hfs_dbg(BNODE_REFS, "find_init: %d (%p)\n",
 		tree->cnid, __builtin_return_address(0));
-	mutex_lock(&tree->tree_lock);
+	switch (tree->cnid) {
+	case HFS_CAT_CNID:
+		mutex_lock_nested(&tree->tree_lock, CATALOG_BTREE_MUTEX);
+		break;
+	case HFS_EXT_CNID:
+		mutex_lock_nested(&tree->tree_lock, EXTENTS_BTREE_MUTEX);
+		break;
+	case HFS_ATTR_CNID:
+		mutex_lock_nested(&tree->tree_lock, ATTR_BTREE_MUTEX);
+		break;
+	default:
+		return -EINVAL;
+	}
 	return 0;
 }
 
diff --git a/fs/hfs/btree.h b/fs/hfs/btree.h
index dcc2aab1b2c4..25ac9a8bb57a 100644
--- a/fs/hfs/btree.h
+++ b/fs/hfs/btree.h
@@ -13,6 +13,13 @@ typedef int (*btree_keycmp)(const btree_key *, const btree_key *);
 
 #define NODE_HASH_SIZE  256
 
+/* B-tree mutex nested subclasses */
+enum hfs_btree_mutex_classes {
+	CATALOG_BTREE_MUTEX,
+	EXTENTS_BTREE_MUTEX,
+	ATTR_BTREE_MUTEX,
+};
+
 /* A HFS BTree held in memory */
 struct hfs_btree {
 	struct super_block *sb;
-- 
2.30.2




  parent reply	other threads:[~2021-07-29 13:56 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-29 13:54 [PATCH 4.19 00/17] 4.19.200-rc1 review Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 01/17] selftest: fix build error in tools/testing/selftests/vm/userfaultfd.c Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 02/17] iio: dac: ds4422/ds4424 drop of_node check Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 03/17] KVM: x86: determine if an exception has an error code only when injecting it Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 04/17] net: split out functions related to registering inflight socket files Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 05/17] af_unix: fix garbage collect vs MSG_PEEK Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 06/17] workqueue: fix UAF in pwq_unbound_release_workfn() Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 07/17] net/802/mrp: fix memleak in mrp_request_join() Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 08/17] net/802/garp: fix memleak in garp_request_join() Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 09/17] net: annotate data race around sk_ll_usec Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 10/17] sctp: move 198 addresses from unusable to private scope Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 11/17] hfs: add missing clean-up in hfs_fill_super Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 12/17] hfs: fix high memory mapping in hfs_bnode_read Greg Kroah-Hartman
2021-07-29 13:54 ` Greg Kroah-Hartman [this message]
2021-07-29 13:54 ` [PATCH 4.19 14/17] firmware: arm_scmi: Fix possible scmi_linux_errmap buffer overflow Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 15/17] firmware: arm_scmi: Fix range check for the maximum number of pending messages Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 16/17] cifs: fix the out of range assignment to bit fields in parse_server_interfaces Greg Kroah-Hartman
2021-07-29 13:54 ` [PATCH 4.19 17/17] ARM: dts: versatile: Fix up interrupt controller node names Greg Kroah-Hartman
2021-07-29 19:47 ` [PATCH 4.19 00/17] 4.19.200-rc1 review Pavel Machek
2021-07-29 22:50 ` Shuah Khan
2021-07-30 10:20 ` Sudip Mukherjee
2021-07-30 11:27 ` Naresh Kamboju
2021-07-31  4:42 ` Guenter Roeck

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