======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc4-syzkaller-00208-g00b827f0cffa #0 Not tainted
------------------------------------------------------
syz.0.0/5315 is trying to acquire lock:
ffff8880525614d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
ffff8880525614d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
ffff8880525614d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4150 [inline]
ffff8880525614d8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0xd2/0xbc0 kernel/workqueue.c:4208

but task is already holding lock:
ffff888052560258 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x255/0x540 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+0x120/0x360 kernel/locking/lockdep.c:5866
       lock_sock_nested+0x48/0x100 net/core/sock.c:3702
       smc_listen_out+0x109/0x3e0 net/smc/af_smc.c:1913
       process_one_work kernel/workqueue.c:3238 [inline]
       process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
       worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
       kthread+0x70e/0x8a0 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+0xb9b/0x2140 kernel/locking/lockdep.c:3909
       __lock_acquire+0xaac/0xd20 kernel/locking/lockdep.c:5235
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       touch_work_lockdep_map kernel/workqueue.c:3922 [inline]
       start_flush_work kernel/workqueue.c:4176 [inline]
       __flush_work+0x6b8/0xbc0 kernel/workqueue.c:4208
       __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4364
       smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29
       __smc_release+0x66b/0x7e0 net/smc/af_smc.c:301
       smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1844
       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:277
       smc_release+0x2ce/0x540 net/smc/af_smc.c:344
       __sock_release net/socket.c:647 [inline]
       sock_close+0xc0/0x240 net/socket.c:1391
       __fput+0x449/0xa70 fs/file_table.c:465
       task_work_run+0x1d1/0x260 kernel/task_work.c:227
       get_signal+0x11c5/0x1310 kernel/signal.c:2807
       arch_do_signal_or_restart+0x95/0x780 arch/x86/kernel/signal.c:337
       exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x8b/0x120 kernel/entry/common.c:218
       do_syscall_64+0x103/0x210 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.0.0/5315:
 #0: ffff88801c17d408 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #0: ffff88801c17d408 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release net/socket.c:646 [inline]
 #0: ffff88801c17d408 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1391
 #1: ffff888052560258 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x255/0x540 net/smc/af_smc.c:-1
 #2: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #2: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #2: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4150 [inline]
 #2: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xd2/0xbc0 kernel/workqueue.c:4208

stack backtrace:
CPU: 0 UID: 0 PID: 5315 Comm: syz.0.0 Not tainted 6.15.0-rc4-syzkaller-00208-g00b827f0cffa #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_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2079
 check_noncircular+0x134/0x160 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+0xb9b/0x2140 kernel/locking/lockdep.c:3909
 __lock_acquire+0xaac/0xd20 kernel/locking/lockdep.c:5235
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
 touch_work_lockdep_map kernel/workqueue.c:3922 [inline]
 start_flush_work kernel/workqueue.c:4176 [inline]
 __flush_work+0x6b8/0xbc0 kernel/workqueue.c:4208
 __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4364
 smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29
 __smc_release+0x66b/0x7e0 net/smc/af_smc.c:301
 smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1844
 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:277
 smc_release+0x2ce/0x540 net/smc/af_smc.c:344
 __sock_release net/socket.c:647 [inline]
 sock_close+0xc0/0x240 net/socket.c:1391
 __fput+0x449/0xa70 fs/file_table.c:465
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 get_signal+0x11c5/0x1310 kernel/signal.c:2807
 arch_do_signal_or_restart+0x95/0x780 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [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+0x8b/0x120 kernel/entry/common.c:218
 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fef6678e969
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:00007fef6760a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000120
RAX: fffffffffffffe00 RBX: 00007fef669b6160 RCX: 00007fef6678e969
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007fef66810ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fef669b6160 R15: 00007ffcac737b38
 </TASK>