INFO: task syslogd:5175 blocked for more than 147 seconds. Not tainted 6.14.0-rc7-syzkaller-00205-g586de92313fc #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syslogd state:D stack:24240 pid:5175 tgid:5175 ppid:1 task_flags:0x400000 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6857 schedule_timeout+0x244/0x280 kernel/time/sleep_timeout.c:75 ___down_common+0x2d7/0x460 kernel/locking/semaphore.c:229 __down_common kernel/locking/semaphore.c:250 [inline] __down+0x20/0x30 kernel/locking/semaphore.c:258 down+0x74/0xa0 kernel/locking/semaphore.c:64 console_lock+0x5b/0xa0 kernel/printk/printk.c:2833 console_device+0x19/0x180 kernel/printk/printk.c:3482 tty_lookup_driver+0x2fb/0x510 drivers/tty/tty_io.c:1930 tty_open_by_driver drivers/tty/tty_io.c:2047 [inline] tty_open+0x54e/0xf80 drivers/tty/tty_io.c:2129 chrdev_open+0x237/0x6a0 fs/char_dev.c:414 do_dentry_open+0x735/0x1c40 fs/open.c:956 vfs_open+0x82/0x3f0 fs/open.c:1086 do_open fs/namei.c:3830 [inline] path_openat+0x1e88/0x2d80 fs/namei.c:3989 do_filp_open+0x20c/0x470 fs/namei.c:4016 do_sys_openat2+0x17a/0x1e0 fs/open.c:1428 do_sys_open fs/open.c:1443 [inline] __do_sys_openat fs/open.c:1459 [inline] __se_sys_openat fs/open.c:1454 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1454 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: 0033:0x7f6302f919a4 RSP: 002b:00007ffc39ed7c10 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f6302f919a4 RDX: 0000000000000901 RSI: 00007f63031303b3 RDI: 00000000ffffff9c RBP: 00007f63031303b3 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000901 R13: 0000000000000901 R14: 0000000000000901 R15: 00005584748b2410 Showing all locks held in the system: 1 lock held by kthreadd/2: 2 locks held by kworker/0:0/9: 2 locks held by kworker/u8:0/12: 2 locks held by kworker/1:0/26: 1 lock held by khungtaskd/31: #0: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746 4 locks held by kworker/u8:2/36: 4 locks held by kworker/1:1/52: 4 locks held by kworker/u8:3/56: 3 locks held by kworker/u8:4/63: 2 locks held by kswapd0/85: 2 locks held by kworker/0:2/118: 3 locks held by kworker/u8:7/1163: 3 locks held by kworker/1:2/1541: 3 locks held by kworker/u8:8/3560: 1 lock held by syslogd/5175: #0: ffffffff8ee88a28 (tty_mutex){+.+.}-{4:4}, at: tty_open_by_driver drivers/tty/tty_io.c:2046 [inline] #0: ffffffff8ee88a28 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x53d/0xf80 drivers/tty/tty_io.c:2129 2 locks held by dhcpcd/5486: 2 locks held by getty/5574: #0: ffff88814d6b20a0 (&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 2 locks held by kworker/1:3/5821: 1 lock held by syz-executor/5863: 4 locks held by syz-executor/5867: 1 lock held by syz-executor/5874: 2 locks held by syz-executor/5876: 2 locks held by kworker/0:5/5912: 2 locks held by kworker/1:4/5913: 2 locks held by kworker/1:5/5920: 2 locks held by kworker/1:6/5942: 6 locks held by syz.1.6228/19744: 5 locks held by kworker/u8:5/19765: 4 locks held by kworker/u8:9/19767: 3 locks held by kworker/u8:10/19768: 3 locks held by syz-executor/19770: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.14.0-rc7-syzkaller-00205-g586de92313fc #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 19768 Comm: kworker/u8:10 Not tainted 6.14.0-rc7-syzkaller-00205-g586de92313fc #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: bat_events batadv_dat_purge RIP: 0010:unwind_next_frame+0xe64/0x20c0 arch/x86/kernel/unwind_orc.c:672 Code: d0 0f 93 c1 48 39 d5 0f 92 c0 84 c1 74 0b 48 39 5c 24 10 0f 83 28 09 00 00 bf 01 00 00 00 e8 b3 bf 1e 00 65 8b 05 74 91 9a 7e <85> c0 0f 84 05 09 00 00 b8 01 00 00 00 e9 ca f1 ff ff ba 28 00 00 RSP: 0018:ffffc90000a27eb8 EFLAGS: 00000293 RAX: 0000000080000101 RBX: ffffc90000a28348 RCX: 0000000000000000 RDX: 0000000000000102 RSI: ffffc90000a28320 RDI: 0000000000000001 RBP: ffffc90000a21000 R08: ffffc90000a27f5c R09: ffffffff918543fe R10: ffffc90000a27f28 R11: 0000000000082d4d R12: ffffc90000a27f78 R13: ffffc90000a27f28 R14: ffffc90000a28348 R15: ffffc90000a28340 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f071b7ffff8 CR3: 000000005f5f2000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x95/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4115 [inline] slab_alloc_node mm/slub.c:4164 [inline] kmem_cache_alloc_noprof+0x226/0x3d0 mm/slub.c:4171 skb_clone+0x190/0x3f0 net/core/skbuff.c:1994 deliver_clone+0x3f/0xa0 net/bridge/br_forward.c:125 maybe_deliver+0xa7/0x120 net/bridge/br_forward.c:190 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:5790 __netif_receive_skb_one_core+0xb1/0x1e0 net/core/dev.c:5894 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6009 process_backlog+0x443/0x15f0 net/core/dev.c:6357 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:7191 napi_poll net/core/dev.c:7260 [inline] net_rx_action+0xa94/0x1010 net/core/dev.c:7382 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] __batadv_dat_purge.part.0+0x279/0x3a0 net/batman-adv/distributed-arp-table.c:185 __batadv_dat_purge net/batman-adv/distributed-arp-table.c:166 [inline] batadv_dat_purge+0x4b/0xa0 net/batman-adv/distributed-arp-table.c:204 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400 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