======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/0:1H/1079 is trying to acquire lock:
ffff888025fe0138 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: __flush_workqueue+0x14c/0x1380 kernel/workqueue.c:2812

but task is already holding lock:
ffffc90004c7fd00 ((work_completion)(&queue->io_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 ((work_completion)(&queue->io_work)){+.+.}-{0:0}:
       __flush_work+0x122/0xac0 kernel/workqueue.c:3072
       __cancel_work_timer+0x3f4/0x560 kernel/workqueue.c:3163
       nvmet_tcp_release_queue_work+0x2ef/0xf30 drivers/nvme/target/tcp.c:1534
       process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
       worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
       kthread+0x29d/0x330 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

-> #1 ((work_completion)(&queue->release_work)){+.+.}-{0:0}:
       process_one_work+0x7ec/0x1160 kernel/workqueue.c:2268
       worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
       kthread+0x29d/0x330 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

-> #0 ((wq_completion)nvmet-wq){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3095 [inline]
       check_prevs_add kernel/locking/lockdep.c:3214 [inline]
       validate_chain kernel/locking/lockdep.c:3830 [inline]
       __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
       lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
       __flush_workqueue+0x165/0x1380 kernel/workqueue.c:2812
       nvmet_tcp_install_queue+0x7e/0x380 drivers/nvme/target/tcp.c:1891
       nvmet_install_queue+0x335/0x760 drivers/nvme/target/fabrics-cmd.c:185
       nvmet_execute_admin_connect+0x332/0x7e0 drivers/nvme/target/fabrics-cmd.c:266
       nvmet_tcp_execute_request drivers/nvme/target/tcp.c:584 [inline]
       nvmet_tcp_try_recv_data drivers/nvme/target/tcp.c:1230 [inline]
       nvmet_tcp_try_recv_one drivers/nvme/target/tcp.c:1294 [inline]
       nvmet_tcp_try_recv drivers/nvme/target/tcp.c:1320 [inline]
       nvmet_tcp_io_work+0x1a52/0x87b0 drivers/nvme/target/tcp.c:1370
       process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
       worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
       kthread+0x29d/0x330 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

other info that might help us debug this:

Chain exists of:
  (wq_completion)nvmet-wq --> (work_completion)(&queue->release_work) --> (work_completion)(&queue->io_work)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((work_completion)(&queue->io_work));
                               lock((work_completion)(&queue->release_work));
                               lock((work_completion)(&queue->io_work));
  lock((wq_completion)nvmet-wq);

 *** DEADLOCK ***

2 locks held by kworker/0:1H/1079:
 #0: ffff888025fe0d38 ((wq_completion)nvmet_tcp_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004c7fd00 ((work_completion)(&queue->io_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267

stack backtrace:
CPU: 0 PID: 1079 Comm: kworker/0:1H Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: nvmet_tcp_wq nvmet_tcp_io_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3095 [inline]
 check_prevs_add kernel/locking/lockdep.c:3214 [inline]
 validate_chain kernel/locking/lockdep.c:3830 [inline]
 __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
 __flush_workqueue+0x165/0x1380 kernel/workqueue.c:2812
 nvmet_tcp_install_queue+0x7e/0x380 drivers/nvme/target/tcp.c:1891
 nvmet_install_queue+0x335/0x760 drivers/nvme/target/fabrics-cmd.c:185
 nvmet_execute_admin_connect+0x332/0x7e0 drivers/nvme/target/fabrics-cmd.c:266
 nvmet_tcp_execute_request drivers/nvme/target/tcp.c:584 [inline]
 nvmet_tcp_try_recv_data drivers/nvme/target/tcp.c:1230 [inline]
 nvmet_tcp_try_recv_one drivers/nvme/target/tcp.c:1294 [inline]
 nvmet_tcp_try_recv drivers/nvme/target/tcp.c:1320 [inline]
 nvmet_tcp_io_work+0x1a52/0x87b0 drivers/nvme/target/tcp.c:1370
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
nvmet: creating nvm controller 1 for subsystem testnqn for NQN nqn.2014-08.org.nvmexpress:uuid:ada1d26d-b54d-4faf-9a1f-57a883becf60.