======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.338/5845 is trying to acquire lock:
ffff88807e7d0910 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0xc1/0x1b0 kernel/workqueue.c:3090

but task is already holding lock:
ffff8880766d8120 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x251/0x530 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+0x44/0x100 net/core/sock.c:3251
       smc_listen_out+0x109/0x3d0 net/smc/af_smc.c:1524
       process_one_work+0x863/0x1000 kernel/workqueue.c:2310
       worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
       kthread+0x436/0x520 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
       lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
       __flush_work+0xdd/0x1b0 kernel/workqueue.c:3090
       __cancel_work_timer+0x3ac/0x520 kernel/workqueue.c:3181
       smc_clcsock_release+0x5c/0xe0 net/smc/smc_close.c:29
       __smc_release+0x398/0x500 net/smc/af_smc.c:211
       smc_close_non_accepted+0xd1/0x1f0 net/smc/af_smc.c:1466
       smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
       smc_close_active+0x9d3/0xd90 net/smc/smc_close.c:219
       __smc_release+0x9a/0x500 net/smc/af_smc.c:187
       smc_release+0x2ca/0x530 net/smc/af_smc.c:254
       __sock_release net/socket.c:649 [inline]
       sock_close+0xd5/0x240 net/socket.c:1336
       __fput+0x234/0x930 fs/file_table.c:311
       task_work_run+0x125/0x1a0 kernel/task_work.c:188
       exit_task_work include/linux/task_work.h:33 [inline]
       do_exit+0x61e/0x20a0 kernel/exit.c:883
       do_group_exit+0x12e/0x300 kernel/exit.c:997
       get_signal+0x6ca/0x12c0 kernel/signal.c:2900
       arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
       handle_signal_work kernel/entry/common.c:154 [inline]
       exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
       exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
       __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
       syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
       do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

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 ***

2 locks held by syz.0.338/5845:
 #0: ffff88807e8b9a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #0: ffff88807e8b9a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:648 [inline]
 #0: ffff88807e8b9a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1336
 #1: ffff8880766d8120 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x251/0x530 net/smc/af_smc.c:-1

stack backtrace:
CPU: 1 PID: 5845 Comm: syz.0.338 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 __flush_work+0xdd/0x1b0 kernel/workqueue.c:3090
 __cancel_work_timer+0x3ac/0x520 kernel/workqueue.c:3181
 smc_clcsock_release+0x5c/0xe0 net/smc/smc_close.c:29
 __smc_release+0x398/0x500 net/smc/af_smc.c:211
 smc_close_non_accepted+0xd1/0x1f0 net/smc/af_smc.c:1466
 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
 smc_close_active+0x9d3/0xd90 net/smc/smc_close.c:219
 __smc_release+0x9a/0x500 net/smc/af_smc.c:187
 smc_release+0x2ca/0x530 net/smc/af_smc.c:254
 __sock_release net/socket.c:649 [inline]
 sock_close+0xd5/0x240 net/socket.c:1336
 __fput+0x234/0x930 fs/file_table.c:311
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0x61e/0x20a0 kernel/exit.c:883
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 get_signal+0x6ca/0x12c0 kernel/signal.c:2900
 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff7d93a5ec9
Code: Unable to access opcode bytes at RIP 0x7ff7d93a5e9f.
RSP: 002b:00007ff7d75ec038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffe00 RBX: 00007ff7d95fd090 RCX: 00007ff7d93a5ec9
RDX: 0000000000000010 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007ff7d9428f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff7d95fd128 R14: 00007ff7d95fd090 R15: 00007fffef1957f8
 </TASK>