======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc2-syzkaller-00042-g1a1d569a75f3 #0 Not tainted
------------------------------------------------------
syz.0.0/5333 is trying to acquire lock:
ffff8880534f14d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
ffff8880534f14d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
ffff8880534f14d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4150 [inline]
ffff8880534f14d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0xee/0xc60 kernel/workqueue.c:4208

but task is already holding lock:
ffff8880534f0258 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x234/0x540 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_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       lock_sock_nested+0x48/0x100 net/core/sock.c:3702
       smc_listen_out+0x11b/0x3e0 net/smc/af_smc.c:1908
       smc_listen_out_connected net/smc/af_smc.c:1928 [inline]
       smc_listen_decline net/smc/af_smc.c:1963 [inline]
       smc_listen_work+0x5b7/0xf30 net/smc/af_smc.c:2559
       process_one_work kernel/workqueue.c:3238 [inline]
       process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
       worker_thread+0x870/0xd50 kernel/workqueue.c:3400
       kthread+0x7b7/0x940 kernel/kthread.c:464
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
       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:3166 [inline]
       check_prevs_add kernel/locking/lockdep.c:3285 [inline]
       validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
       __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
       lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
       touch_work_lockdep_map kernel/workqueue.c:3922 [inline]
       start_flush_work kernel/workqueue.c:4176 [inline]
       __flush_work+0x75b/0xc60 kernel/workqueue.c:4208
       __cancel_work_sync+0xbc/0x110 kernel/workqueue.c:4364
       smc_clcsock_release+0x62/0xf0 net/smc/smc_close.c:29
       __smc_release+0x683/0x800 net/smc/af_smc.c:301
       smc_close_non_accepted+0xd8/0x1f0 net/smc/af_smc.c:1839
       smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
       smc_close_active+0xadb/0xe90 net/smc/smc_close.c:225
       __smc_release+0xa0/0x800 net/smc/af_smc.c:277
       smc_release+0x2dc/0x540 net/smc/af_smc.c:344
       __sock_release net/socket.c:647 [inline]
       sock_close+0xbc/0x240 net/socket.c:1391
       __fput+0x3e9/0x9f0 fs/file_table.c:465
       task_work_run+0x251/0x310 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
       do_syscall_64+0x100/0x230 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.0.0/5333:
 #0: ffff888012c46c08 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #0: ffff888012c46c08 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: __sock_release net/socket.c:646 [inline]
 #0: ffff888012c46c08 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: sock_close+0x90/0x240 net/socket.c:1391
 #1: ffff8880534f0258 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x234/0x540 net/smc/af_smc.c:-1
 #2: ffffffff8ed3dfa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #2: ffffffff8ed3dfa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #2: ffffffff8ed3dfa0 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4150 [inline]
 #2: ffffffff8ed3dfa0 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xee/0xc60 kernel/workqueue.c:4208

stack backtrace:
CPU: 0 UID: 0 PID: 5333 Comm: syz.0.0 Not tainted 6.15.0-rc2-syzkaller-00042-g1a1d569a75f3 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2079
 check_noncircular+0x142/0x160 kernel/locking/lockdep.c:2211
 check_prev_add kernel/locking/lockdep.c:3166 [inline]
 check_prevs_add kernel/locking/lockdep.c:3285 [inline]
 validate_chain+0xa69/0x24e0 kernel/locking/lockdep.c:3909
 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
 touch_work_lockdep_map kernel/workqueue.c:3922 [inline]
 start_flush_work kernel/workqueue.c:4176 [inline]
 __flush_work+0x75b/0xc60 kernel/workqueue.c:4208
 __cancel_work_sync+0xbc/0x110 kernel/workqueue.c:4364
 smc_clcsock_release+0x62/0xf0 net/smc/smc_close.c:29
 __smc_release+0x683/0x800 net/smc/af_smc.c:301
 smc_close_non_accepted+0xd8/0x1f0 net/smc/af_smc.c:1839
 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
 smc_close_active+0xadb/0xe90 net/smc/smc_close.c:225
 __smc_release+0xa0/0x800 net/smc/af_smc.c:277
 smc_release+0x2dc/0x540 net/smc/af_smc.c:344
 __sock_release net/socket.c:647 [inline]
 sock_close+0xbc/0x240 net/socket.c:1391
 __fput+0x3e9/0x9f0 fs/file_table.c:465
 task_work_run+0x251/0x310 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f178e78e169
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:00007ffcb399d238 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 0000000000010dec RCX: 00007f178e78e169
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f178e9b7ba0 R08: 0000000000000001 R09: 0000001eb399d52f
R10: 00007f178e5ff02c R11: 0000000000000246 R12: 00007f178e9b5fac
R13: 00007f178e9b5fa0 R14: ffffffffffffffff R15: 00007ffcb399d350
 </TASK>