]> git.ipfire.org Git - thirdparty/kernel/stable.git/commit
hfs: add lock nesting notation to hfs_find_init
authorDesmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Thu, 15 Jul 2021 04:27:08 +0000 (21:27 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 4 Aug 2021 09:56:45 +0000 (11:56 +0200)
commitb81e38f97662aa8f66a6dcd7d11c93cc5db3f53a
tree11912e76273f8a33defb052d00aff04b48b5dc1d
parent6c2803d4b67b8b087e39f15db40b652d2f83fed7
hfs: add lock nesting notation to hfs_find_init

[ 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
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
fs/hfs/btree.h