From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, desmondcheongzx@gmail.com,
gregkh@linuxfoundation.org, gustavoars@kernel.org,
linux-mm@kvack.org, mm-commits@vger.kernel.org,
skhan@linuxfoundation.org, slava@dubeyko.com,
torvalds@linux-foundation.org, viro@zeniv.linux.org.uk
Subject: [patch 12/13] hfs: add lock nesting notation to hfs_find_init
Date: Wed, 14 Jul 2021 21:27:08 -0700 [thread overview]
Message-ID: <20210715042708.eP0VysJim%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210714212609.fad116e584ba1194981a6294@linux-foundation.org>
From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Subject: hfs: add lock nesting notation to hfs_find_init
Syzbot reports a possible recursive lock:
https://syzkaller.appspot.com/bug?id=f007ef1d7a31a469e3be7aeb0fde0769b18585db
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://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>
---
fs/hfs/bfind.c | 14 +++++++++++++-
fs/hfs/btree.h | 7 +++++++
2 files changed, 20 insertions(+), 1 deletion(-)
--- a/fs/hfs/bfind.c~hfs-add-lock-nesting-notation-to-hfs_find_init
+++ a/fs/hfs/bfind.c
@@ -25,7 +25,19 @@ int hfs_find_init(struct hfs_btree *tree
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;
}
--- a/fs/hfs/btree.h~hfs-add-lock-nesting-notation-to-hfs_find_init
+++ a/fs/hfs/btree.h
@@ -13,6 +13,13 @@ typedef int (*btree_keycmp)(const btree_
#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;
_
next prev parent reply other threads:[~2021-07-15 4:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-15 4:26 incoming Andrew Morton
2021-07-15 4:26 ` [patch 01/13] mm: move helper to check slub_debug_enabled Andrew Morton
2021-07-15 4:26 ` [patch 02/13] kasan: add memzero init for unaligned size at DEBUG Andrew Morton
2021-07-15 4:26 ` [patch 03/13] kasan: fix build by including kernel.h Andrew Morton
2021-07-15 4:26 ` [patch 04/13] Revert "mm/page_alloc: make should_fail_alloc_page() static" Andrew Morton
2021-07-15 4:26 ` [patch 05/13] mm/page_alloc: avoid page allocator recursion with pagesets.lock held Andrew Morton
2021-07-15 4:26 ` [patch 06/13] mm/page_alloc: correct return value when failing at preparing Andrew Morton
2021-07-15 4:26 ` [patch 07/13] mm/page_alloc: further fix __alloc_pages_bulk() return value Andrew Morton
2021-07-15 4:26 ` [patch 08/13] mm: fix the try_to_unmap prototype for !CONFIG_MMU Andrew Morton
2021-07-15 4:26 ` [patch 09/13] lib/test_hmm: remove set but unused page variable Andrew Morton
2021-07-15 4:27 ` [patch 10/13] hfs: add missing clean-up in hfs_fill_super Andrew Morton
2021-07-15 4:27 ` [patch 11/13] hfs: fix high memory mapping in hfs_bnode_read Andrew Morton
2021-07-15 4:27 ` Andrew Morton [this message]
2021-07-15 4:27 ` [patch 13/13] mm/hugetlb: fix refs calculation from unaligned @vaddr Andrew Morton
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