======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.1975/13119 is trying to acquire lock:
ffff88807ef896d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
ffff88807ef896d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
ffff88807ef896d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4187 [inline]
ffff88807ef896d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0xd2/0xbc0 kernel/workqueue.c:4245

but task is already holding lock:
ffff88807ef88260 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x255/0x560 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+0x48/0x100 net/core/sock.c:3780
       smc_listen_out+0x109/0x3e0 net/smc/af_smc.c:1925
       process_one_work+0x93a/0x15a0 kernel/workqueue.c:3261
       process_scheduled_works kernel/workqueue.c:3344 [inline]
       worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425
       kthread+0x711/0x8a0 kernel/kthread.c:463
       ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

-> #0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
       touch_work_lockdep_map kernel/workqueue.c:3959 [inline]
       start_flush_work kernel/workqueue.c:4213 [inline]
       __flush_work+0x6b8/0xbc0 kernel/workqueue.c:4245
       __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4401
       smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29
       __smc_release+0x66b/0x7e0 net/smc/af_smc.c:305
       smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1856
       smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
       smc_close_active+0xb68/0xf10 net/smc/smc_close.c:225
       __smc_release+0x8d/0x7e0 net/smc/af_smc.c:281
       smc_release+0x2ce/0x560 net/smc/af_smc.c:348
       __sock_release+0xb9/0x250 net/socket.c:657
       sock_close+0x1c/0x30 net/socket.c:1461
       __fput+0x44c/0xa70 fs/file_table.c:468
       task_work_run+0x1d4/0x260 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:44 [inline]
       exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75
       __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
       syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
       syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
       syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
       do_syscall_64+0x2e3/0xf80 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.1.1975/13119:
 #0: ffff88805d58ef48 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
 #0: ffff88805d58ef48 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x89/0x250 net/socket.c:656
 #1: ffff88807ef88260 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x255/0x560 net/smc/af_smc.c:-1
 #2: ffffffff8e3419e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #2: ffffffff8e3419e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #2: ffffffff8e3419e0 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4187 [inline]
 #2: ffffffff8e3419e0 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xd2/0xbc0 kernel/workqueue.c:4245

stack backtrace:
CPU: 1 UID: 0 PID: 13119 Comm: syz.1.1975 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
 touch_work_lockdep_map kernel/workqueue.c:3959 [inline]
 start_flush_work kernel/workqueue.c:4213 [inline]
 __flush_work+0x6b8/0xbc0 kernel/workqueue.c:4245
 __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4401
 smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29
 __smc_release+0x66b/0x7e0 net/smc/af_smc.c:305
 smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1856
 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
 smc_close_active+0xb68/0xf10 net/smc/smc_close.c:225
 __smc_release+0x8d/0x7e0 net/smc/af_smc.c:281
 smc_release+0x2ce/0x560 net/smc/af_smc.c:348
 __sock_release+0xb9/0x250 net/socket.c:657
 sock_close+0x1c/0x30 net/socket.c:1461
 __fput+0x44c/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 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:44 [inline]
 exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc70378f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc70461b038 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fc7039e5fa0 RCX: 00007fc70378f749
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000000
RBP: 00007fc703813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc7039e6038 R14: 00007fc7039e5fa0 R15: 00007ffcd2401438
 </TASK>