====================================================== WARNING: possible circular locking dependency detected 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0 Not tainted ------------------------------------------------------ syz.0.991/9541 is trying to acquire lock: ffff88803220a058 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] ffff88803220a058 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] ffff88803220a058 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4150 [inline] ffff88803220a058 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0xd2/0xbc0 kernel/workqueue.c:4208 but task is already holding lock: ffff888032208dd8 (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.0.991/9541: #0: ffff88807c710808 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] #0: ffff88807c710808 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: __sock_release net/socket.c:646 [inline] #0: ffff88807c710808 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1391 #1: ffff888032208dd8 (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: 1 UID: 0 PID: 9541 Comm: syz.0.991 Not tainted 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Call Trace: 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: 0033:0x7f6b4758e969 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:00007f6b48393038 EFLAGS: 00000246 ORIG_RAX: 0000000000000120 RAX: fffffffffffffe00 RBX: 00007f6b477b5fa0 RCX: 00007f6b4758e969 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000009 RBP: 00007f6b47610ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000800 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f6b477b5fa0 R15: 00007ffc13ecd438