====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.6.4750/26570 is trying to acquire lock: ffff88805501e870 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] ffff88805501e870 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] ffff88805501e870 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4280 [inline] ffff88805501e870 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x101/0xd70 kernel/workqueue.c:4338 but task is already holding lock: ffff88805501ee18 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x22f/0x580 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+0x41/0x130 net/core/sock.c:3825 smc_listen_out+0x105/0x3c0 net/smc/af_smc.c:1935 smc_listen_work+0x81d/0x1410 net/smc/af_smc.c:-1 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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 kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1520/0x2ce0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 touch_work_lockdep_map kernel/workqueue.c:4052 [inline] start_flush_work kernel/workqueue.c:4306 [inline] __flush_work+0x6c5/0xd70 kernel/workqueue.c:4338 __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4494 smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29 __smc_release+0x662/0x7d0 net/smc/af_smc.c:318 smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1866 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline] smc_close_active+0xb6b/0xf50 net/smc/smc_close.c:225 __smc_release+0x9e/0x7d0 net/smc/af_smc.c:294 smc_release+0x2cd/0x580 net/smc/af_smc.c:361 __sock_release net/socket.c:710 [inline] sock_close+0xad/0x220 net/socket.c:1501 __fput+0x42a/0xa80 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x1182/0x12c0 kernel/signal.c:2810 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x104/0x730 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:318 [inline] do_syscall_64+0x353/0x580 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.6.4750/26570: #0: ffff88805161b1f8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] #0: ffff88805161b1f8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release net/socket.c:709 [inline] #0: ffff88805161b1f8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: sock_close+0x82/0x220 net/socket.c:1501 #1: ffff88805501ee18 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x22f/0x580 net/smc/af_smc.c:-1 #2: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #2: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #2: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4280 [inline] #2: ffffffff8dfc2fc0 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x101/0xd70 kernel/workqueue.c:4338 stack backtrace: CPU: 1 UID: 0 PID: 26570 Comm: syz.6.4750 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 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+0x1520/0x2ce0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 touch_work_lockdep_map kernel/workqueue.c:4052 [inline] start_flush_work kernel/workqueue.c:4306 [inline] __flush_work+0x6c5/0xd70 kernel/workqueue.c:4338 __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4494 smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29 __smc_release+0x662/0x7d0 net/smc/af_smc.c:318 smc_close_non_accepted+0xd5/0x1f0 net/smc/af_smc.c:1866 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline] smc_close_active+0xb6b/0xf50 net/smc/smc_close.c:225 __smc_release+0x9e/0x7d0 net/smc/af_smc.c:294 smc_release+0x2cd/0x580 net/smc/af_smc.c:361 __sock_release net/socket.c:710 [inline] sock_close+0xad/0x220 net/socket.c:1501 __fput+0x42a/0xa80 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x1182/0x12c0 kernel/signal.c:2810 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x104/0x730 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:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc83e40ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc83c624028 EFLAGS: 00000246 ORIG_RAX: 0000000000000120 RAX: fffffffffffffe00 RBX: 00007fc83e686180 RCX: 00007fc83e40ce59 RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000005 RBP: 00007fc83e4a2e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc83e686218 R14: 00007fc83e686180 R15: 00007ffc13369508