======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L      
------------------------------------------------------
syz.6.4931/25329 is trying to acquire lock:
ffff888066dcbc70 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
ffff888066dcbc70 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
ffff888066dcbc70 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4515 [inline]
ffff888066dcbc70 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x101/0xd30 kernel/workqueue.c:4573

but task is already holding lock:
ffff88807d2127e0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x24d/0x550 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+0x41/0x100 net/core/sock.c:3908
       smc_listen_out+0xd4/0x3d0 net/smc/af_smc.c:1940
       smc_listen_work+0x81d/0x1410 net/smc/af_smc.c:-1
       process_one_work kernel/workqueue.c:3495 [inline]
       process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
       kthread+0x38b/0x480 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:4287 [inline]
       start_flush_work kernel/workqueue.c:4541 [inline]
       __flush_work+0x7a6/0xd30 kernel/workqueue.c:4573
       __cancel_work_sync kernel/workqueue.c:4729 [inline]
       cancel_work_sync+0xb8/0xf0 kernel/workqueue.c:4766
       smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29
       __smc_release+0x64e/0x7c0 net/smc/af_smc.c:318
       smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1870
       smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
       smc_close_active+0xbd8/0x1000 net/smc/smc_close.c:226
       __smc_release+0x9c/0x7c0 net/smc/af_smc.c:294
       smc_release+0x2c5/0x550 net/smc/af_smc.c:361
       __sock_release+0xa0/0x1f0 net/socket.c:735
       sock_close+0x1c/0x30 net/socket.c:1529
       __fput+0x408/0xa40 fs/file_table.c:512
       task_work_run+0x1d9/0x260 kernel/task_work.c:233
       get_signal+0x117c/0x12c0 kernel/signal.c:2884
       arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
       __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
       exit_to_user_mode_loop+0x10e/0x770 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:343 [inline]
       do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
       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 ***

locks held by syz.6.4931/25329: 3, last CPU#1:
 #0: ffff8880545d0dc0 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #0: ffff8880545d0dc0 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x7a/0x1f0 net/socket.c:734
 #1: ffff88807d2127e0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x24d/0x550 net/smc/af_smc.c:-1
 #2: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #2: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #2: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4515 [inline]
 #2: ffffffff8ff5a320 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x101/0xd30 kernel/workqueue.c:4573

stack backtrace:
CPU: 1 UID: 0 PID: 25329 Comm: syz.6.4931 Tainted: G             L       syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
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:4287 [inline]
 start_flush_work kernel/workqueue.c:4541 [inline]
 __flush_work+0x7a6/0xd30 kernel/workqueue.c:4573
 __cancel_work_sync kernel/workqueue.c:4729 [inline]
 cancel_work_sync+0xb8/0xf0 kernel/workqueue.c:4766
 smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29
 __smc_release+0x64e/0x7c0 net/smc/af_smc.c:318
 smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1870
 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
 smc_close_active+0xbd8/0x1000 net/smc/smc_close.c:226
 __smc_release+0x9c/0x7c0 net/smc/af_smc.c:294
 smc_release+0x2c5/0x550 net/smc/af_smc.c:361
 __sock_release+0xa0/0x1f0 net/socket.c:735
 sock_close+0x1c/0x30 net/socket.c:1529
 __fput+0x408/0xa40 fs/file_table.c:512
 task_work_run+0x1d9/0x260 kernel/task_work.c:233
 get_signal+0x117c/0x12c0 kernel/signal.c:2884
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x10e/0x770 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:343 [inline]
 do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1d2e79f559
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:00007f1d2f5e6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000120
RAX: fffffffffffffe00 RBX: 00007f1d2ea26090 RCX: 00007f1d2e79f559
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007
RBP: 00007f1d2e836b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000800 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1d2ea26128 R14: 00007f1d2ea26090 R15: 00007f1d2eb4fa48
 </TASK>