====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.4.1334/9977 is trying to acquire lock: ffff8880316748e8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] ffff8880316748e8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] ffff8880316748e8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4354 [inline] ffff8880316748e8 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x101/0xca0 kernel/workqueue.c:4412 but task is already holding lock: ffff8880316759e0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x24d/0x550 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+0x41/0x100 net/core/sock.c:3837 smc_listen_out+0xd4/0x3d0 net/smc/af_smc.c:1934 smc_listen_work+0x81d/0x1410 net/smc/af_smc.c:-1 process_one_work kernel/workqueue.c:3396 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560 kthread+0x38b/0x480 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:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 touch_work_lockdep_map kernel/workqueue.c:4126 [inline] start_flush_work kernel/workqueue.c:4380 [inline] __flush_work+0x74c/0xca0 kernel/workqueue.c:4412 __cancel_work_sync+0xbf/0x110 kernel/workqueue.c:4568 smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29 __smc_release+0x64e/0x7c0 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+0xb30/0xf20 net/smc/smc_close.c:225 __smc_release+0x9c/0x7c0 net/smc/af_smc.c:294 smc_release+0x2c5/0x550 net/smc/af_smc.c:361 __sock_release+0xa0/0x1f0 net/socket.c:735 sock_close+0x1c/0x30 net/socket.c:1526 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 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+0x204/0x770 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:343 [inline] __do_fast_syscall_32+0x437/0x6b0 arch/x86/entry/syscall_32.c:294 do_fast_syscall_32+0x33/0x70 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.4.1334/9977: 3, last CPU#0: #0: ffff888069d67b00 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] #0: ffff888069d67b00 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x7a/0x1f0 net/socket.c:734 #1: ffff8880316759e0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x24d/0x550 net/smc/af_smc.c:-1 #2: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #2: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4354 [inline] #2: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x101/0xca0 kernel/workqueue.c:4412 stack backtrace: CPU: 0 UID: 0 PID: 9977 Comm: syz.4.1334 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219 check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 touch_work_lockdep_map kernel/workqueue.c:4126 [inline] start_flush_work kernel/workqueue.c:4380 [inline] __flush_work+0x74c/0xca0 kernel/workqueue.c:4412 __cancel_work_sync+0xbf/0x110 kernel/workqueue.c:4568 smc_clcsock_release+0x60/0xf0 net/smc/smc_close.c:29 __smc_release+0x64e/0x7c0 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+0xb30/0xf20 net/smc/smc_close.c:225 __smc_release+0x9c/0x7c0 net/smc/af_smc.c:294 smc_release+0x2c5/0x550 net/smc/af_smc.c:361 __sock_release+0xa0/0x1f0 net/socket.c:735 sock_close+0x1c/0x30 net/socket.c:1526 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 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+0x204/0x770 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:343 [inline] __do_fast_syscall_32+0x437/0x6b0 arch/x86/entry/syscall_32.c:294 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:316 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf706f0ec Code: 90 85 d2 74 0a 89 ce 81 e6 ff 0f 00 00 89 32 85 c0 74 05 c1 e9 0c 89 08 31 c0 5e 5d c3 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 58 b8 RSP: 002b:00000000f545d50c EFLAGS: 00000206 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00000000ffffffff RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 90 nop 1: 85 d2 test %edx,%edx 3: 74 0a je 0xf 5: 89 ce mov %ecx,%esi 7: 81 e6 ff 0f 00 00 and $0xfff,%esi d: 89 32 mov %esi,(%rdx) f: 85 c0 test %eax,%eax 11: 74 05 je 0x18 13: c1 e9 0c shr $0xc,%ecx 16: 89 08 mov %ecx,(%rax) 18: 31 c0 xor %eax,%eax 1a: 5e pop %rsi 1b: 5d pop %rbp 1c: c3 ret 1d: 90 nop 1e: 0f 1f 00 nopl (%rax) 21: 51 push %rcx 22: 52 push %rdx 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 ret 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 90 nop 33: 90 nop 34: 90 nop 35: 90 nop 36: 90 nop 37: 90 nop 38: 90 nop 39: 90 nop 3a: 90 nop 3b: 90 nop 3c: 90 nop 3d: 90 nop 3e: 58 pop %rax 3f: b8 .byte 0xb8