INFO: task syslogd:5173 blocked for more than 143 seconds. Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syslogd state:D stack:24240 pid:5173 tgid:5173 ppid:1 task_flags:0x400000 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5377 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6764 __schedule_loop kernel/sched/core.c:6841 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6856 schedule_timeout+0x244/0x280 kernel/time/sleep_timeout.c:75 ___down_common+0x2d7/0x460 kernel/locking/semaphore.c:225 __down_common kernel/locking/semaphore.c:246 [inline] __down+0x20/0x30 kernel/locking/semaphore.c:254 down+0x74/0xa0 kernel/locking/semaphore.c:63 console_lock+0x5b/0xa0 kernel/printk/printk.c:2833 do_con_write+0x154/0x7bb0 drivers/tty/vt/vt.c:3056 con_write+0x23/0xb0 drivers/tty/vt/vt.c:3432 process_output_block drivers/tty/n_tty.c:574 [inline] n_tty_write+0x419/0x1140 drivers/tty/n_tty.c:2389 iterate_tty_write drivers/tty/tty_io.c:1015 [inline] file_tty_write.constprop.0+0x506/0x9a0 drivers/tty/tty_io.c:1090 redirected_tty_write+0x7c/0x140 drivers/tty/tty_io.c:1130 new_sync_write fs/read_write.c:586 [inline] vfs_write+0x5ae/0x1150 fs/read_write.c:679 ksys_write+0x12b/0x250 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb552db6bf2 RSP: 002b:00007ffcd5819e88 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fb552db6bf2 RDX: 0000000000000051 RSI: 000056347ad00600 RDI: 0000000000000003 RBP: 000056347ad00600 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000051 R13: 00007fb552c62480 R14: 0000000000000003 R15: 000056347ad00410 Showing all locks held in the system: 2 locks held by kworker/0:0/8: 2 locks held by kworker/0:1/9: 7 locks held by kworker/u8:0/11: 3 locks held by kworker/u8:1/12: 3 locks held by kworker/1:0/25: #0: ffff88801b078d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc900001f7d18 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 #2: ffffffff8e1c8038 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x282/0x3b0 kernel/rcu/tree_exp.h:302 1 lock held by khungtaskd/30: #0: ffffffff8e1bcbc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e1bcbc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e1bcbc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746 1 lock held by kswapd0/88: 3 locks held by kworker/u8:5/966: 3 locks held by kworker/u8:7/4134: 4 locks held by syslogd/5173: #0: ffff88803d6c10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffff88803d6c1130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: tty_write_lock drivers/tty/tty_io.c:948 [inline] #1: ffff88803d6c1130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: iterate_tty_write drivers/tty/tty_io.c:967 [inline] #1: ffff88803d6c1130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: file_tty_write.constprop.0+0x281/0x9a0 drivers/tty/tty_io.c:1090 #2: ffff88803d6c12e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_write+0x1bd/0x1140 drivers/tty/n_tty.c:2372 #3: ffffc9001cf83380 (&ldata->output_lock){+.+.}-{4:4}, at: process_output_block drivers/tty/n_tty.c:529 [inline] #3: ffffc9001cf83380 (&ldata->output_lock){+.+.}-{4:4}, at: n_tty_write+0x533/0x1140 drivers/tty/n_tty.c:2389 2 locks held by dhcpcd/5484: 2 locks held by getty/5570: #0: ffff88814d23f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211 1 lock held by syz-executor/5801: 4 locks held by kworker/1:4/6171: 2 locks held by syz-executor/6179: 2 locks held by syz-executor/6187: 2 locks held by syz-executor/6190: 3 locks held by kworker/0:4/6218: 6 locks held by syz.0.5387/16922: 2 locks held by kworker/u8:9/16954: 3 locks held by kworker/u8:10/16955: 2 locks held by syz-executor/16956: 2 locks held by kworker/0:8/16957: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline] watchdog+0xf62/0x12b0 kernel/hung_task.c:399 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 11 Comm: kworker/u8:0 Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline] RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] RIP: 0010:rcu_is_watching+0x58/0xc0 kernel/rcu/tree.c:716 Code: 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 5c 48 03 1c ed e0 ec aa 8d 48 b8 00 00 00 00 00 fc ff df 48 89 da <48> c1 ea 03 0f b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 04 84 RSP: 0018:ffffc90000007318 EFLAGS: 00000286 RAX: dffffc0000000000 RBX: ffff8880b8637be8 RCX: ffffffff8a26ea59 RDX: ffff8880b8637be8 RSI: ffffffff8bd33ce0 RDI: ffffffff8daaece0 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000001 R13: ffff888055d3a800 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd0cd64c630 CR3: 000000000df80000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:109 [inline] rcu_read_lock_held+0x1e/0x50 kernel/rcu/update.c:349 nbp_vlan_group_rcu net/bridge/br_private.h:1614 [inline] should_deliver+0x29f/0x380 net/bridge/br_forward.c:26 maybe_deliver+0x56/0x120 net/bridge/br_forward.c:182 br_flood+0x17b/0x5e0 net/bridge/br_forward.c:237 br_handle_frame_finish+0xea2/0x1c90 net/bridge/br_input.c:220 br_nf_hook_thresh+0x303/0x410 net/bridge/br_netfilter_hooks.c:1170 br_nf_pre_routing_finish_ipv6+0x76a/0xfb0 net/bridge/br_netfilter_ipv6.c:154 NF_HOOK include/linux/netfilter.h:314 [inline] br_nf_pre_routing_ipv6+0x3ce/0x8c0 net/bridge/br_netfilter_ipv6.c:184 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_bridge_pre net/bridge/br_input.c:282 [inline] br_handle_frame+0xad7/0x14a0 net/bridge/br_input.c:433 __netif_receive_skb_core.constprop.0+0xa20/0x4330 net/core/dev.c:5722 __netif_receive_skb_one_core+0xb1/0x1e0 net/core/dev.c:5826 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5941 process_backlog+0x443/0x15f0 net/core/dev.c:6289 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:7106 napi_poll net/core/dev.c:7175 [inline] net_rx_action+0xa94/0x1010 net/core/dev.c:7297 handle_softirqs+0x213/0x8f0 kernel/softirq.c:561 do_softirq kernel/softirq.c:462 [inline] do_softirq+0xb2/0xf0 kernel/softirq.c:449 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:389 spin_unlock_bh include/linux/spinlock.h:396 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline] nsim_dev_trap_report_work+0x8c7/0xd00 drivers/net/netdevsim/dev.c:851 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244