======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.1.701/9276 is trying to acquire lock:
ffff88803b9a8cf0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
ffff88803b9a8cf0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
ffff88803b9a8cf0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4284 [inline]
ffff88803b9a8cf0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x101/0xd70 kernel/workqueue.c:4342

but task is already holding lock:
ffff88803b9a9298 (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:3825
       smc_listen_out+0x105/0x3c0 net/smc/af_smc.c:1935
       smc_listen_work+0x81d/0x1410 net/smc/af_smc.c:-1
       process_one_work+0x93a/0x12b0 kernel/workqueue.c:3326
       process_scheduled_works kernel/workqueue.c:3409 [inline]
       worker_thread+0xb05/0x10d0 kernel/workqueue.c:3490
       kthread+0x388/0x470 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:3167 [inline]
       check_prevs_add kernel/locking/lockdep.c:3286 [inline]
       validate_chain kernel/locking/lockdep.c:3910 [inline]
       __lock_acquire+0x1520/0x2ce0 kernel/locking/lockdep.c:5239
       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870
       touch_work_lockdep_map kernel/workqueue.c:4056 [inline]
       start_flush_work kernel/workqueue.c:4310 [inline]
       __flush_work+0x6c5/0xd70 kernel/workqueue.c:4342
       __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4498
       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+0xb6b/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:714
       sock_close+0x1c/0x30 net/socket.c:1516
       __fput+0x42a/0xa80 fs/file_table.c:512
       task_work_run+0x1d9/0x270 kernel/task_work.c:233
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       __exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
       exit_to_user_mode_loop+0x1fa/0x730 kernel/entry/common.c:101
       __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
       syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
       syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
       do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

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 ***

3 locks held by syz.1.701/9276:
 #0: ffff88803fa03f78 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #0: ffff88803fa03f78 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x7a/0x1f0 net/socket.c:713
 #1: ffff88803b9a9298 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x22f/0x580 net/smc/af_smc.c:-1
 #2: ffffffff8dfc3040 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #2: ffffffff8dfc3040 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #2: ffffffff8dfc3040 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4284 [inline]
 #2: ffffffff8dfc3040 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x101/0xd70 kernel/workqueue.c:4342

stack backtrace:
CPU: 0 UID: 0 PID: 9276 Comm: syz.1.701 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2045
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3167 [inline]
 check_prevs_add kernel/locking/lockdep.c:3286 [inline]
 validate_chain kernel/locking/lockdep.c:3910 [inline]
 __lock_acquire+0x1520/0x2ce0 kernel/locking/lockdep.c:5239
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870
 touch_work_lockdep_map kernel/workqueue.c:4056 [inline]
 start_flush_work kernel/workqueue.c:4310 [inline]
 __flush_work+0x6c5/0xd70 kernel/workqueue.c:4342
 __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4498
 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+0xb6b/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:714
 sock_close+0x1c/0x30 net/socket.c:1516
 __fput+0x42a/0xa80 fs/file_table.c:512
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
 exit_to_user_mode_loop+0x1fa/0x730 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f266e63ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc53325158 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f266e8b7da0 RCX: 00007f266e63ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f266e8b7da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007f266e8b7cb0 R11: 0000000000000246 R12: 0000000000067544
R13: 00007f266e8b636c R14: 0000000000067460 R15: 00007f266e8b6360
 </TASK>