====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.6235/26198 is trying to acquire lock: ffff88804d241bc8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] ffff88804d241bc8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] ffff88804d241bc8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4179 [inline] ffff88804d241bc8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0xce/0xd20 kernel/workqueue.c:4237 but task is already holding lock: ffff88803b1d1250 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x24d/0x5a0 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:5868 lock_sock_nested+0x3e/0x130 net/core/sock.c:3720 smc_listen_out+0x109/0x3e0 net/smc/af_smc.c:1924 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4b9/0x870 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 kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 touch_work_lockdep_map kernel/workqueue.c:3951 [inline] start_flush_work kernel/workqueue.c:4205 [inline] __flush_work+0x6f0/0xd20 kernel/workqueue.c:4237 __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4393 smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29 __smc_release+0x6a0/0x810 net/smc/af_smc.c:304 smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1855 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline] smc_close_active+0xb9c/0xf40 net/smc/smc_close.c:225 __smc_release+0xa0/0x810 net/smc/af_smc.c:280 smc_release+0x2eb/0x5a0 net/smc/af_smc.c:347 __sock_release net/socket.c:662 [inline] sock_close+0xc0/0x240 net/socket.c:1455 __fput+0x458/0xa80 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:227 get_signal+0x11c4/0x1310 kernel/signal.c:2807 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 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.3.6235/26198: #0: ffff88803d3b56f8 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline] #0: ffff88803d3b56f8 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: __sock_release net/socket.c:661 [inline] #0: ffff88803d3b56f8 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1455 #1: ffff88803b1d1250 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x24d/0x5a0 net/smc/af_smc.c:-1 #2: ffffffff8d7aa500 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #2: ffffffff8d7aa500 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #2: ffffffff8d7aa500 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4179 [inline] #2: ffffffff8d7aa500 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xce/0xd20 kernel/workqueue.c:4237 stack backtrace: CPU: 1 UID: 0 PID: 26198 Comm: syz.3.6235 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 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+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 touch_work_lockdep_map kernel/workqueue.c:3951 [inline] start_flush_work kernel/workqueue.c:4205 [inline] __flush_work+0x6f0/0xd20 kernel/workqueue.c:4237 __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4393 smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29 __smc_release+0x6a0/0x810 net/smc/af_smc.c:304 smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1855 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline] smc_close_active+0xb9c/0xf40 net/smc/smc_close.c:225 __smc_release+0xa0/0x810 net/smc/af_smc.c:280 smc_release+0x2eb/0x5a0 net/smc/af_smc.c:347 __sock_release net/socket.c:662 [inline] sock_close+0xc0/0x240 net/socket.c:1455 __fput+0x458/0xa80 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:227 get_signal+0x11c4/0x1310 kernel/signal.c:2807 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5582beeec9 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:00007f55809f1038 EFLAGS: 00000246 ORIG_RAX: 000000000000002b RAX: fffffffffffffe00 RBX: 00007f5582e46270 RCX: 00007f5582beeec9 RDX: 0000000000000000 RSI: 0000200000004ec0 RDI: 0000000000000007 RBP: 00007f5582c71f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5582e46308 R14: 00007f5582e46270 R15: 00007fff0d349e78