======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.3.255/6855 is trying to acquire lock:
ffff88806bed61e8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: touch_work_lockdep_map kernel/workqueue.c:4126 [inline]
ffff88806bed61e8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4380 [inline]
ffff88806bed61e8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x4ca/0xcb0 kernel/workqueue.c:4412

but task is already holding lock:
ffff88806bed72e0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x3a5/0x620 net/smc/af_smc.c:353

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 kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       lock_sock_nested+0x41/0xf0 net/core/sock.c:3830
       smc_listen_out+0xf2/0x4b0 net/smc/af_smc.c:1934
       smc_listen_out_connected net/smc/af_smc.c:1956 [inline]
       smc_listen_decline net/smc/af_smc.c:1991 [inline]
       smc_listen_work+0x767/0x50e0 net/smc/af_smc.c:2588
       process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396
       process_scheduled_works kernel/workqueue.c:3479 [inline]
       worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560
       kthread+0x373/0x450 kernel/kthread.c:436
       ret_from_fork+0x730/0xd60 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+0xeb/0xe60 kernel/locking/lockdep.c:3181
       check_prevs_add kernel/locking/lockdep.c:3300 [inline]
       validate_chain kernel/locking/lockdep.c:3924 [inline]
       __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5254
       lock_acquire kernel/locking/lockdep.c:5908 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
       touch_work_lockdep_map kernel/workqueue.c:4126 [inline]
       start_flush_work kernel/workqueue.c:4380 [inline]
       __flush_work+0x4de/0xcb0 kernel/workqueue.c:4412
       __cancel_work_sync kernel/workqueue.c:4568 [inline]
       cancel_work_sync+0xd1/0xf0 kernel/workqueue.c:4605
       smc_clcsock_release+0x5f/0xe0 net/smc/smc_close.c:29
       __smc_release+0x5c2/0x880 net/smc/af_smc.c:318
       smc_close_non_accepted+0xda/0x200 net/smc/af_smc.c:1866
       smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
       smc_close_active+0x4ff/0x1060 net/smc/smc_close.c:225
       __smc_release+0x634/0x880 net/smc/af_smc.c:294
       smc_release+0x1fc/0x620 net/smc/af_smc.c:361
       __sock_release+0xb3/0x260 net/socket.c:735
       sock_close+0x1c/0x30 net/socket.c:1526
       __fput+0x3ff/0xb50 fs/file_table.c:512
       task_work_run+0x150/0x240 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:70 [inline]
       exit_to_user_mode_loop+0x1d8/0x700 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:336 [inline]
       __do_fast_syscall_32+0x59f/0x8b0 arch/x86/entry/syscall_32.c:294
       do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
       entry_SYSENTER_compat_after_hwframe+0x84/0x8e

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.3.255/6855: 3, last CPU#0:
 #0: ffff8880004b4d00 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #0: ffff8880004b4d00 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x86/0x260 net/socket.c:734
 #1: ffff88806bed72e0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x3a5/0x620 net/smc/af_smc.c:353
 #2: ffffffff8edebe60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #2: ffffffff8edebe60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #2: ffffffff8edebe60 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4354 [inline]
 #2: ffffffff8edebe60 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xfd/0xcb0 kernel/workqueue.c:4412

stack backtrace:
CPU: 0 UID: 0 PID: 6855 Comm: syz.3.255 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2059
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2191
 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
 check_prevs_add kernel/locking/lockdep.c:3300 [inline]
 validate_chain kernel/locking/lockdep.c:3924 [inline]
 __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5254
 lock_acquire kernel/locking/lockdep.c:5908 [inline]
 lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5865
 touch_work_lockdep_map kernel/workqueue.c:4126 [inline]
 start_flush_work kernel/workqueue.c:4380 [inline]
 __flush_work+0x4de/0xcb0 kernel/workqueue.c:4412
 __cancel_work_sync kernel/workqueue.c:4568 [inline]
 cancel_work_sync+0xd1/0xf0 kernel/workqueue.c:4605
 smc_clcsock_release+0x5f/0xe0 net/smc/smc_close.c:29
 __smc_release+0x5c2/0x880 net/smc/af_smc.c:318
 smc_close_non_accepted+0xda/0x200 net/smc/af_smc.c:1866
 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline]
 smc_close_active+0x4ff/0x1060 net/smc/smc_close.c:225
 __smc_release+0x634/0x880 net/smc/af_smc.c:294
 smc_release+0x1fc/0x620 net/smc/af_smc.c:361
 __sock_release+0xb3/0x260 net/socket.c:735
 sock_close+0x1c/0x30 net/socket.c:1526
 __fput+0x3ff/0xb50 fs/file_table.c:512
 task_work_run+0x150/0x240 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:70 [inline]
 exit_to_user_mode_loop+0x1d8/0x700 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:336 [inline]
 __do_fast_syscall_32+0x59f/0x8b0 arch/x86/entry/syscall_32.c:294
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf6feefec
Code: Unable to access opcode bytes at 0xf6feefc2.
RSP: 002b:00000000f53dd50c EFLAGS: 00000292 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00000000ffffffff
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>