======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/0:0/9 is trying to acquire lock:
ffff8880514877b0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
ffff8880514877b0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
ffff8880514877b0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4354 [inline]
ffff8880514877b0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x101/0xd70 kernel/workqueue.c:4412

but task is already holding lock:
ffff888067138358 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x22f/0x580 net/smc/af_smc.c:-1

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sk_lock-AF_SMC/1){+.+.}-{0:0}:
       lock_sock_nested+0x41/0x130 net/core/sock.c:3837
       smc_listen_out+0xd4/0x3d0 net/smc/af_smc.c:1934
       process_one_work kernel/workqueue.c:3396 [inline]
       process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
       kthread+0x38b/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3209 [inline]
       check_prevs_add kernel/locking/lockdep.c:3328 [inline]
       validate_chain kernel/locking/lockdep.c:3952 [inline]
       __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
       lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
       touch_work_lockdep_map kernel/workqueue.c:4126 [inline]
       start_flush_work kernel/workqueue.c:4380 [inline]
       __flush_work+0x6c5/0xd70 kernel/workqueue.c:4412
       __cancel_work_sync+0xbf/0x110 kernel/workqueue.c:4568
       smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29
       __smc_release+0x662/0x7d0 net/smc/af_smc.c:318
       smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1866
       smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
       smc_close_active+0xb59/0xf50 net/smc/smc_close.c:225
       __smc_release+0x9e/0x7d0 net/smc/af_smc.c:294
       smc_release+0x2cd/0x580 net/smc/af_smc.c:361
       __sock_release+0xa0/0x1f0 net/socket.c:735
       sock_close+0x1c/0x30 net/socket.c:1526
       __fput+0x42a/0xa80 fs/file_table.c:512
       delayed_fput+0x63/0xa0 fs/file_table.c:535
       process_one_work kernel/workqueue.c:3396 [inline]
       process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
       kthread+0x38b/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sk_lock-AF_SMC/1);
                               lock((work_completion)(&new_smc->smc_listen_work));
                               lock(sk_lock-AF_SMC/1);
  lock((work_completion)(&new_smc->smc_listen_work));

 *** DEADLOCK ***

locks held by kworker/0:0/9: 5, last CPU#0:
 #0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc900000e7c40 ((delayed_fput_work).work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc900000e7c40 ((delayed_fput_work).work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc900000e7c40 ((delayed_fput_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc900000e7c40 ((delayed_fput_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff88805e6f4cf8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #2: ffff88805e6f4cf8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release+0x7a/0x1f0 net/socket.c:734
 #3: ffff888067138358 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x22f/0x580 net/smc/af_smc.c:-1
 #4: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #4: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #4: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4354 [inline]
 #4: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x101/0xd70 kernel/workqueue.c:4412

stack backtrace:
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: events delayed_fput
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087
 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219
 check_prev_add kernel/locking/lockdep.c:3209 [inline]
 check_prevs_add kernel/locking/lockdep.c:3328 [inline]
 validate_chain kernel/locking/lockdep.c:3952 [inline]
 __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 touch_work_lockdep_map kernel/workqueue.c:4126 [inline]
 start_flush_work kernel/workqueue.c:4380 [inline]
 __flush_work+0x6c5/0xd70 kernel/workqueue.c:4412
 __cancel_work_sync+0xbf/0x110 kernel/workqueue.c:4568
 smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29
 __smc_release+0x662/0x7d0 net/smc/af_smc.c:318
 smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1866
 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
 smc_close_active+0xb59/0xf50 net/smc/smc_close.c:225
 __smc_release+0x9e/0x7d0 net/smc/af_smc.c:294
 smc_release+0x2cd/0x580 net/smc/af_smc.c:361
 __sock_release+0xa0/0x1f0 net/socket.c:735
 sock_close+0x1c/0x30 net/socket.c:1526
 __fput+0x42a/0xa80 fs/file_table.c:512
 delayed_fput+0x63/0xa0 fs/file_table.c:535
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>