linux/fs/overlayfs
Amir Goldstein 6cd078702f ovl: fix recursive oi->lock in ovl_link()
linking a non-copied-up file into a non-copied-up parent results in a
nested call to mutex_lock_interruptible(&oi->lock). Fix this by copying up
target parent before ovl_nlink_start(), same as done in ovl_rename().

~/unionmount-testsuite$ ./run --ov -s
~/unionmount-testsuite$ ln /mnt/a/foo100 /mnt/a/dir100/

 WARNING: possible recursive locking detected
 --------------------------------------------
 ln/1545 is trying to acquire lock:
 00000000bcce7c4c (&ovl_i_lock_key[depth]){+.+.}, at:
     ovl_copy_up_start+0x28/0x7d
 but task is already holding lock:
 0000000026d73d5b (&ovl_i_lock_key[depth]){+.+.}, at:
     ovl_nlink_start+0x3c/0xc1

[SzM: this seems to be a false positive, but doing the copy-up first is
harmless and removes the lockdep splat]

Reported-by: syzbot+3ef5c0d1a5cb0b21e6be@syzkaller.appspotmail.com
Fixes: 5f8415d6b8 ("ovl: persistent overlay inode nlink for...")
Cc: <stable@vger.kernel.org> # v4.13
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-26 23:34:39 +02:00
..
copy_up.c ovl: clean up error handling in ovl_get_tmpfile() 2018-10-26 23:34:39 +02:00
dir.c ovl: fix recursive oi->lock in ovl_link() 2018-10-26 23:34:39 +02:00
export.c ovl: Modify ovl_lookup() and friends to lookup metacopy dentry 2018-07-20 09:56:09 +02:00
file.c vfs: swap names of {do,vfs}_clone_file_range() 2018-09-24 10:54:01 +02:00
inode.c ovl: make symbol 'ovl_aops' static 2018-09-25 20:41:23 +02:00
Kconfig ovl: Provide a mount option metacopy=on/off for metadata copyup 2018-07-20 09:56:06 +02:00
Makefile ovl: stack file ops 2018-07-18 15:44:41 +02:00
namei.c ovl: fix error handling in ovl_verify_set_fh() 2018-10-26 23:34:39 +02:00
overlayfs.h ovl: fix format of setxattr debug 2018-10-04 14:49:10 +02:00
ovl_entry.h ovl: Store lower data inode in ovl_inode 2018-07-20 09:56:11 +02:00
readdir.c ovl: fix wrong use of impure dir cache in ovl_iterate() 2018-07-17 16:04:34 +02:00
super.c ovl: fix oopses in ovl_fill_super() failure paths 2018-09-10 12:55:49 +02:00
util.c ovl: fix memory leak on unlink of indexed file 2018-09-24 10:54:01 +02:00