======================================================
WARNING: possible circular locking dependency detected
4.14.307-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/10044 is trying to acquire lock:
 (&bdev->bd_mutex){+.+.}, at: [<ffffffff830c548b>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192

but task is already holding lock:
 (&nbd->config_lock){+.+.}, at: [<ffffffff838e839f>] nbd_ioctl+0x11f/0xad0 drivers/block/nbd.c:1369

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&nbd->config_lock){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893
       nbd_open+0x1ac/0x370 drivers/block/nbd.c:1422
       __blkdev_get+0x306/0x1090 fs/block_dev.c:1470
       blkdev_get+0x88/0x890 fs/block_dev.c:1611
       blkdev_open+0x1cc/0x250 fs/block_dev.c:1772
       do_dentry_open+0x44b/0xec0 fs/open.c:777
       vfs_open+0x105/0x220 fs/open.c:888
       do_last fs/namei.c:3428 [inline]
       path_openat+0x628/0x2970 fs/namei.c:3571
       do_filp_open+0x179/0x3c0 fs/namei.c:3605
       do_sys_open+0x296/0x410 fs/open.c:1081
       do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
       entry_SYSCALL_64_after_hwframe+0x5e/0xd3

-> #1 (nbd_index_mutex){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893
       nbd_open+0x1e/0x370 drivers/block/nbd.c:1409
       __blkdev_get+0x306/0x1090 fs/block_dev.c:1470
       blkdev_get+0x88/0x890 fs/block_dev.c:1611
       blkdev_open+0x1cc/0x250 fs/block_dev.c:1772
       do_dentry_open+0x44b/0xec0 fs/open.c:777
       vfs_open+0x105/0x220 fs/open.c:888
       do_last fs/namei.c:3428 [inline]
       path_openat+0x628/0x2970 fs/namei.c:3571
       do_filp_open+0x179/0x3c0 fs/namei.c:3605
       do_sys_open+0x296/0x410 fs/open.c:1081
       do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
       entry_SYSCALL_64_after_hwframe+0x5e/0xd3

-> #0 (&bdev->bd_mutex){+.+.}:
       lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893
       blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
       nbd_bdev_reset drivers/block/nbd.c:1076 [inline]
       nbd_clear_sock_ioctl drivers/block/nbd.c:1282 [inline]
       __nbd_ioctl drivers/block/nbd.c:1306 [inline]
       nbd_ioctl+0x802/0xad0 drivers/block/nbd.c:1376
       __blkdev_driver_ioctl block/ioctl.c:297 [inline]
       blkdev_ioctl+0x540/0x1830 block/ioctl.c:594
       block_ioctl+0xd9/0x120 fs/block_dev.c:1893
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:500 [inline]
       do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
       SYSC_ioctl fs/ioctl.c:701 [inline]
       SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
       do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
       entry_SYSCALL_64_after_hwframe+0x5e/0xd3

other info that might help us debug this:

Chain exists of:
  &bdev->bd_mutex --> nbd_index_mutex --> &nbd->config_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&nbd->config_lock);
                               lock(nbd_index_mutex);
                               lock(&nbd->config_lock);
  lock(&bdev->bd_mutex);

 *** DEADLOCK ***

1 lock held by syz-executor.1/10044:
 #0:  (&nbd->config_lock){+.+.}, at: [<ffffffff838e839f>] nbd_ioctl+0x11f/0xad0 drivers/block/nbd.c:1369

stack backtrace:
CPU: 0 PID: 10044 Comm: syz-executor.1 Not tainted 4.14.307-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258
 check_prev_add kernel/locking/lockdep.c:1905 [inline]
 check_prevs_add kernel/locking/lockdep.c:2022 [inline]
 validate_chain kernel/locking/lockdep.c:2464 [inline]
 __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491
 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
 __mutex_lock_common kernel/locking/mutex.c:756 [inline]
 __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 nbd_bdev_reset drivers/block/nbd.c:1076 [inline]
 nbd_clear_sock_ioctl drivers/block/nbd.c:1282 [inline]
 __nbd_ioctl drivers/block/nbd.c:1306 [inline]
 nbd_ioctl+0x802/0xad0 drivers/block/nbd.c:1376
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x540/0x1830 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1893
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x5e/0xd3
RIP: 0033:0x7f825b6a00f9
RSP: 002b:00007f8259bf1168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f825b7c0050 RCX: 00007f825b6a00f9
RDX: 0000000000000000 RSI: 000000000000ab04 RDI: 0000000000000004
RBP: 00007f825b6fbae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdbf20ceff R14: 00007f8259bf1300 R15: 0000000000022000
EXT4-fs error (device loop2): ext4_orphan_get:1265: comm syz-executor.2: bad orphan inode 16
IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready
ext4_test_bit(bit=15, block=3) = 0
EXT4-fs (loop2): mounted filesystem without journal. Opts: grpjquota=Cnoblock_validity,acl,jqfmt=vfsv0,data_err=abort,grpquota,noquota,prjquota,dioread_lock,noblock_validity,usrjquota=,resuid=0x0000000000000000,,errors=continue
BTRFS: device fsid d552757d-9c39-40e3-95f0-16d819589928 devid 1 transid 8 /dev/loop5
BTRFS error (device loop5): unsupported checksum algorithm 2
IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready
BTRFS error (device loop5): superblock checksum mismatch
BTRFS: device fsid 24c7a497-3402-47dd-bef8-82358f5f30e0 
IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready
devid 1 transid 8 /dev/loop0
BTRFS info (device loop0): enabling inode map caching
BTRFS warning (device loop0): excessive commit interval 622039222
BTRFS info (device loop0): force zlib compression
BTRFS error (device loop5): open_ctree failed
BTRFS info (device loop0): using free space tree
BTRFS info (device loop0): has skinny extents
BTRFS error (device loop4): unsupported checksum algorithm 2
BTRFS error (device loop4): superblock checksum mismatch
BTRFS error (device loop4): open_ctree failed
EXT4-fs (loop2): filesystem is read-only
[EXT4 FS bs=4096, gc=1, bpg=32768, ipg=32, mo=9826c018, mo2=0002]
EXT4-fs (loop2): filesystem is read-only
EXT4-fs (loop2): orphan cleanup on readonly fs
EXT4-fs (loop2): Cannot turn on journaled quota: type 1: error -2
EXT4-fs error (device loop2): ext4_orphan_get:1265: comm syz-executor.2: bad orphan inode 16
ext4_test_bit(bit=15, block=3) = 0
EXT4-fs (loop2): mounted filesystem without journal. Opts: grpjquota=Cnoblock_validity,acl,jqfmt=vfsv0,data_err=abort,grpquota,noquota,prjquota,dioread_lock,noblock_validity,usrjquota=,resuid=0x0000000000000000,,errors=continue
EXT4-fs (loop2): filesystem is read-only
[EXT4 FS bs=4096, gc=1, bpg=32768, ipg=32, mo=9826c018, mo2=0002]
EXT4-fs (loop2): filesystem is read-only
EXT4-fs (loop2): orphan cleanup on readonly fs
EXT4-fs (loop2): Cannot turn on journaled quota: type 1: error -2
EXT4-fs error (device loop2): ext4_orphan_get:1265: comm syz-executor.2: bad orphan inode 16
ext4_test_bit(bit=15, block=3) = 0
EXT4-fs (loop2): mounted filesystem without journal. Opts: grpjquota=Cnoblock_validity,acl,jqfmt=vfsv0,data_err=abort,grpquota,noquota,prjquota,dioread_lock,noblock_validity,usrjquota=,resuid=0x0000000000000000,,errors=continue
BTRFS info (device loop0): enabling inode map caching
BTRFS warning (device loop0): excessive commit interval 622039222
F2FS-fs (loop5): Mismatch start address, segment0(512) cp_blkaddr(605)
BTRFS info (device loop0): force zlib compression
F2FS-fs (loop5): Can't find valid F2FS filesystem in 1th superblock
BTRFS info (device loop0): using free space tree
F2FS-fs (loop5): invalid crc value
BTRFS info (device loop0): has skinny extents
F2FS-fs (loop5): Found nat_bits in checkpoint
F2FS-fs (loop5): Mounted with checkpoint version = 753bd00b
audit: type=1804 audit(1678016924.845:2): pid=10173 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir1933517545/syzkaller.aA1vZT/28/bus/bus" dev="loop5" ino=4 res=1
audit: type=1804 audit(1678016924.845:3): pid=10173 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir1933517545/syzkaller.aA1vZT/28/bus/bus" dev="loop5" ino=4 res=1
BTRFS info (device loop0): enabling inode map caching
BTRFS warning (device loop0): excessive commit interval 622039222
BTRFS info (device loop0): force zlib compression
BTRFS info (device loop0): using free space tree
BTRFS info (device loop0): has skinny extents
F2FS-fs (loop5): Mismatch start address, segment0(512) cp_blkaddr(605)
F2FS-fs (loop5): Can't find valid F2FS filesystem in 1th superblock
F2FS-fs (loop1): Mismatch start address, segment0(512) cp_blkaddr(605)
F2FS-fs (loop5): invalid crc value
F2FS-fs (loop1): Can't find valid F2FS filesystem in 1th superblock
audit: type=1804 audit(1678016925.646:4): pid=10267 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir1202212899/syzkaller.mGuZc0/39/bus/bus" dev="loop1" ino=4 res=1
audit: type=1804 audit(1678016925.646:5): pid=10260 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir1933517545/syzkaller.aA1vZT/29/bus/bus" dev="loop5" ino=4 res=1
audit: type=1804 audit(1678016925.646:6): pid=10260 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir1933517545/syzkaller.aA1vZT/29/bus/bus" dev="loop5" ino=4 res=1
audit: type=1804 audit(1678016925.676:7): pid=10267 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir1202212899/syzkaller.mGuZc0/39/bus/bus" dev="loop1" ino=4 res=1
NILFS (loop0): invalid segment: Checksum error in segment payload
NILFS (loop0): trying rollback from an earlier position
NILFS (loop0): invalid segment: Checksum error in segment payload
NILFS (loop0): error -22 while searching super root
audit: type=1804 audit(1678016926.256:8): pid=10390 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir1933517545/syzkaller.aA1vZT/30/bus/bus" dev="loop5" ino=4 res=1
audit: type=1804 audit(1678016926.256:9): pid=10390 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir1933517545/syzkaller.aA1vZT/30/bus/bus" dev="loop5" ino=4 res=1
audit: type=1804 audit(1678016926.306:10): pid=10397 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir1202212899/syzkaller.mGuZc0/40/bus/bus" dev="loop1" ino=4 res=1
audit: type=1804 audit(1678016926.306:11): pid=10397 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir1202212899/syzkaller.mGuZc0/40/bus/bus" dev="loop1" ino=4 res=1
attempt to access beyond end of device
NILFS (loop4): segctord starting. Construction interval = 5 seconds, CP frequency < 30 seconds
loop4: rw=0, want=8590065738, limit=2048
NILFS (loop4): I/O error reading meta-data file (ino=6, block-offset=1)
Zero length message leads to an empty skb
could not allocate digest TFM handle nhpoly1305-avx2
NILFS (loop3): broken superblock, retrying with spare superblock (blocksize = 1024)
NILFS (loop3): invalid segment: Checksum error in segment payload
NILFS (loop3): unable to fall back to spare super block
NILFS (loop3): error -22 while searching super root
could not allocate digest TFM handle nhpoly1305-avx2
unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1
could not allocate digest TFM handle nhpoly1305-avx2
could not allocate digest TFM handle nhpoly1305-avx2
could not allocate digest TFM handle nhpoly1305-avx2
BTRFS info (device loop1): enabling inode map caching
BTRFS warning (device loop1): excessive commit interval 622039222
BTRFS info (device loop1): force zlib compression
BTRFS info (device loop1): using free space tree
BTRFS info (device loop1): has skinny extents
f2fs_msg: 25 callbacks suppressed
F2FS-fs (loop3): Found nat_bits in checkpoint
F2FS-fs (loop3): Mounted with checkpoint version = 48b305e5
kauditd_printk_skb: 6 callbacks suppressed
audit: type=1800 audit(1678016931.276:18): pid=10959 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="bus" dev="loop3" ino=10 res=0
attempt to access beyond end of device
loop3: rw=2049, want=45104, limit=40427
Bluetooth: hci4 command 0x0409 tx timeout
F2FS-fs (loop3): Found nat_bits in checkpoint
F2FS-fs (loop3): Mounted with checkpoint version = 48b305e5
audit: type=1800 audit(1678016931.606:19): pid=11028 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="bus" dev="loop3" ino=10 res=0
attempt to access beyond end of device
loop3: rw=2049, want=45104, limit=40427
BTRFS info (device loop1): enabling inode map caching
BTRFS warning (device loop1): excessive commit interval 622039222
BTRFS info (device loop1): force zlib compression
BTRFS info (device loop1): using free space tree
BTRFS info (device loop1): has skinny extents
F2FS-fs (loop3): Found nat_bits in checkpoint
F2FS-fs (loop3): Mounted with checkpoint version = 48b305e5
audit: type=1800 audit(1678016932.116:20): pid=11072 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="bus" dev="loop3" ino=10 res=0
attempt to access beyond end of device
loop3: rw=2049, want=45104, limit=40427
F2FS-fs (loop3): Found nat_bits in checkpoint
BTRFS info (device loop1): enabling inode map caching
BTRFS warning (device loop1): excessive commit interval 622039222
BTRFS info (device loop1): force zlib compression
BTRFS info (device loop1): using free space tree
BTRFS info (device loop1): has skinny extents
F2FS-fs (loop3): Mounted with checkpoint version = 48b305e5
audit: type=1800 audit(1678016932.576:21): pid=11153 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="bus" dev="loop3" ino=10 res=0
attempt to access beyond end of device
loop3: rw=2049, want=45104, limit=40427
BTRFS info (device loop1): enabling inode map caching
BTRFS warning (device loop1): excessive commit interval 622039222
BTRFS info (device loop1): force zlib compression
BTRFS info (device loop1): using free space tree
BTRFS info (device loop1): has skinny extents