syzbot

======================================================
WARNING: possible circular locking dependency detected
6.14.0-syzkaller-13423-ga8662bcd2ff1 #0 Not tainted
------------------------------------------------------
syz.2.1271/10250 is trying to acquire lock:
ffff888056740dd8 (sk_lock-AF_SMC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1615 [inline]
ffff888056740dd8 (sk_lock-AF_SMC){+.+.}-{0:0}, at: smc_shutdown+0x65/0x7f0 net/smc/af_smc.c:2930

but task is already holding lock:
ffff8880440b8870 (&nsock->tx_lock){+.+.}-{4:4}, at: sock_shutdown+0x16f/0x280 drivers/block/nbd.c:410

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
       sock_shutdown+0x16f/0x280 drivers/block/nbd.c:410
       nbd_clear_sock drivers/block/nbd.c:1416 [inline]
       nbd_config_put+0x1e6/0x750 drivers/block/nbd.c:1440
       nbd_release+0xb7/0x190 drivers/block/nbd.c:1735
       blkdev_put_whole+0xad/0xf0 block/bdev.c:683
       bdev_release+0x47e/0x6d0 block/bdev.c:1106
       blkdev_release+0x15/0x20 block/fops.c:660
       __fput+0x3ff/0xb70 fs/file_table.c:465
       task_work_run+0x14d/0x240 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
       do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&nbd->config_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
       refcount_dec_and_mutex_lock+0x51/0xc0 lib/refcount.c:118
       nbd_config_put+0x31/0x750 drivers/block/nbd.c:1423
       nbd_release+0xb7/0x190 drivers/block/nbd.c:1735
       blkdev_put_whole+0xad/0xf0 block/bdev.c:683
       bdev_release+0x47e/0x6d0 block/bdev.c:1106
       blkdev_release+0x15/0x20 block/fops.c:660
       __fput+0x3ff/0xb70 fs/file_table.c:465
       fput_close_sync+0x15e/0x1e0 fs/file_table.c:570
       __do_sys_close fs/open.c:1581 [inline]
       __se_sys_close fs/open.c:1566 [inline]
       __x64_sys_close+0x8b/0x120 fs/open.c:1566
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (&disk->open_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
       bdev_open+0x41a/0xe40 block/bdev.c:907
       bdev_file_open_by_dev block/bdev.c:1021 [inline]
       bdev_file_open_by_dev+0x17d/0x210 block/bdev.c:996
       disk_scan_partitions+0x1ed/0x320 block/genhd.c:374
       add_disk_fwnode+0x1060/0x13a0 block/genhd.c:526
       pmem_attach_disk+0x981/0x1350 drivers/nvdimm/pmem.c:574
       nd_pmem_probe+0x1a9/0x1f0 drivers/nvdimm/pmem.c:647
       nvdimm_bus_probe+0x169/0x5d0 drivers/nvdimm/bus.c:94
       call_driver_probe drivers/base/dd.c:579 [inline]
       really_probe+0x23e/0xa90 drivers/base/dd.c:658
       __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800
       driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830
       __driver_attach+0x283/0x580 drivers/base/dd.c:1216
       bus_for_each_dev+0x13b/0x1d0 drivers/base/bus.c:370
       bus_add_driver+0x2e9/0x690 drivers/base/bus.c:678
       driver_register+0x15c/0x4b0 drivers/base/driver.c:249
       __nd_driver_register+0x103/0x1a0 drivers/nvdimm/bus.c:622
       do_one_initcall+0x120/0x6e0 init/main.c:1257
       do_initcall_level init/main.c:1319 [inline]
       do_initcalls init/main.c:1335 [inline]
       do_basic_setup init/main.c:1354 [inline]
       kernel_init_freeable+0x5c2/0x900 init/main.c:1567
       kernel_init+0x1c/0x2b0 init/main.c:1457
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #3 (&nvdimm_namespace_key){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
       device_lock include/linux/device.h:922 [inline]
       uevent_show+0x187/0x3b0 drivers/base/core.c:2730
       dev_attr_show+0x53/0xe0 drivers/base/core.c:2424
       sysfs_kf_seq_show+0x213/0x3e0 fs/sysfs/file.c:65
       seq_read_iter+0x506/0x12c0 fs/seq_file.c:230
       kernfs_fop_read_iter+0x40f/0x5a0 fs/kernfs/file.c:279
       new_sync_read fs/read_write.c:489 [inline]
       vfs_read+0x8c8/0xc70 fs/read_write.c:570
       ksys_read+0x12a/0x240 fs/read_write.c:713
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (kn->active#5){++++}-{0:0}:
       kernfs_drain+0x4af/0x570 fs/kernfs/dir.c:511
       __kernfs_remove+0x271/0x890 fs/kernfs/dir.c:1506
       kernfs_remove_by_name_ns+0x68/0x110 fs/kernfs/dir.c:1714
       sysfs_remove_file include/linux/sysfs.h:794 [inline]
       device_remove_file drivers/base/core.c:3048 [inline]
       device_remove_file drivers/base/core.c:3044 [inline]
       device_del+0x381/0x9f0 drivers/base/core.c:3853
       unregister_netdevice_many_notify+0x17eb/0x25a0 net/core/dev.c:12016
       unregister_netdevice_many net/core/dev.c:12044 [inline]
       unregister_netdevice_queue+0x305/0x3f0 net/core/dev.c:11896
       unregister_netdevice include/linux/netdevice.h:3374 [inline]
       unregister_netdev+0x1f/0x60 net/core/dev.c:12062
       slip_close+0x165/0x1c0 drivers/net/slip/slip.c:906
       tty_ldisc_close+0x111/0x1a0 drivers/tty/tty_ldisc.c:455
       tty_ldisc_kill+0x8e/0x150 drivers/tty/tty_ldisc.c:613
       tty_ldisc_release+0x109/0x2e0 drivers/tty/tty_ldisc.c:781
       tty_release_struct+0x23/0xe0 drivers/tty/tty_io.c:1690
       tty_release+0xe2d/0x1430 drivers/tty/tty_io.c:1861
       __fput+0x3ff/0xb70 fs/file_table.c:465
       task_work_run+0x14d/0x240 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
       do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (rtnl_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
       smc_vlan_by_tcpsk+0x251/0x620 net/smc/smc_core.c:1908
       __smc_connect+0x44b/0x4880 net/smc/af_smc.c:1520
       smc_connect+0x2fc/0x760 net/smc/af_smc.c:1696
       __sys_connect_file+0x13e/0x1a0 net/socket.c:2038
       __sys_connect+0x14d/0x170 net/socket.c:2057
       __do_sys_connect net/socket.c:2063 [inline]
       __se_sys_connect net/socket.c:2060 [inline]
       __x64_sys_connect+0x72/0xb0 net/socket.c:2060
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (sk_lock-AF_SMC){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3166 [inline]
       check_prevs_add kernel/locking/lockdep.c:3285 [inline]
       validate_chain kernel/locking/lockdep.c:3909 [inline]
       __lock_acquire+0x1173/0x1ba0 kernel/locking/lockdep.c:5235
       lock_acquire kernel/locking/lockdep.c:5866 [inline]
       lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823
       lock_sock_nested+0x41/0xf0 net/core/sock.c:3697
       lock_sock include/net/sock.h:1615 [inline]
       smc_shutdown+0x65/0x7f0 net/smc/af_smc.c:2930
       nbd_mark_nsock_dead+0xae/0x5d0 drivers/block/nbd.c:318
       sock_shutdown+0x17c/0x280 drivers/block/nbd.c:411
       nbd_clear_sock drivers/block/nbd.c:1416 [inline]
       nbd_config_put+0x1e6/0x750 drivers/block/nbd.c:1440
       nbd_release+0xb7/0x190 drivers/block/nbd.c:1735
       blkdev_put_whole+0xad/0xf0 block/bdev.c:683
       bdev_release+0x47e/0x6d0 block/bdev.c:1106
       blkdev_release+0x15/0x20 block/fops.c:660
       __fput+0x3ff/0xb70 fs/file_table.c:465
       task_work_run+0x14d/0x240 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
       do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  sk_lock-AF_SMC --> &nbd->config_lock --> &nsock->tx_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&nsock->tx_lock);
                               lock(&nbd->config_lock);
                               lock(&nsock->tx_lock);
  lock(sk_lock-AF_SMC);

 *** DEADLOCK ***

3 locks held by syz.2.1271/10250:
 #0: ffff88802678b358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x15a/0x6d0 block/bdev.c:1090
 #1: ffff888107078998 (&nbd->config_lock){+.+.}-{4:4}, at: refcount_dec_and_mutex_lock+0x51/0xc0 lib/refcount.c:118
 #2: ffff8880440b8870 (&nsock->tx_lock){+.+.}-{4:4}, at: sock_shutdown+0x16f/0x280 drivers/block/nbd.c:410

stack backtrace:
CPU: 2 UID: 0 PID: 10250 Comm: syz.2.1271 Not tainted 6.14.0-syzkaller-13423-ga8662bcd2ff1 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2079
 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2211
 check_prev_add kernel/locking/lockdep.c:3166 [inline]
 check_prevs_add kernel/locking/lockdep.c:3285 [inline]
 validate_chain kernel/locking/lockdep.c:3909 [inline]
 __lock_acquire+0x1173/0x1ba0 kernel/locking/lockdep.c:5235
 lock_acquire kernel/locking/lockdep.c:5866 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823
 lock_sock_nested+0x41/0xf0 net/core/sock.c:3697
 lock_sock include/net/sock.h:1615 [inline]
 smc_shutdown+0x65/0x7f0 net/smc/af_smc.c:2930
 nbd_mark_nsock_dead+0xae/0x5d0 drivers/block/nbd.c:318
 sock_shutdown+0x17c/0x280 drivers/block/nbd.c:411
 nbd_clear_sock drivers/block/nbd.c:1416 [inline]
 nbd_config_put+0x1e6/0x750 drivers/block/nbd.c:1440
 nbd_release+0xb7/0x190 drivers/block/nbd.c:1735
 blkdev_put_whole+0xad/0xf0 block/bdev.c:683
 bdev_release+0x47e/0x6d0 block/bdev.c:1106
 blkdev_release+0x15/0x20 block/fops.c:660
 __fput+0x3ff/0xb70 fs/file_table.c:465
 task_work_run+0x14d/0x240 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f485ed8d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff9c86a748 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f485efa7ba0 RCX: 00007f485ed8d169
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f485efa7ba0 R08: 0000000000000154 R09: 000000149c86aa3f
R10: 00007f485efa7ac0 R11: 0000000000000246 R12: 000000000001df3b
R13: 00007f485efa6160 R14: ffffffffffffffff R15: 00007fff9c86a860
 </TASK>
block nbd2: shutting down sockets