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Commit b3b2177a authored by Desmond Cheong Zhi Xi's avatar Desmond Cheong Zhi Xi Committed by Linus Torvalds
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hfs: add lock nesting notation to hfs_find_init

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: default avatarDesmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reported-by: default avatar <syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com>
Tested-by: default avatar <syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com>
Reviewed-by: default avatarViacheslav 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 54a5ead6
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