INFO: task syz.4.2634:14717 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.2634 state:D stack:23880 pid:14717 tgid:14716 ppid:10100 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5598 [inline] __schedule+0x1ba5/0x5f70 kernel/sched/core.c:7401 __schedule_loop kernel/sched/core.c:7478 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7493 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7550 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7c4/0x15a0 kernel/locking/mutex.c:821 sync_bdevs+0x294/0x480 block/bdev.c:1378 ksys_sync+0x104/0x150 fs/sync.c:106 __ia32_sys_sync+0xe/0x20 fs/sync.c:112 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x171/0x540 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x00007ff76d3a8f19 RSP: 002b:00007ff76e181028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007ff76d625fa0 RCX: 00007ff76d3a8f19 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ff76d625fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff76d626038 R14: 00007ff76d625fa0 R15: 00007ffdf90b5838 Showing all locks held in the system: locks held by khungtaskd/37: 1, on CPU#1: #0: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871 locks held by udevd/5007: 1, on CPU#1: #0: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline] #0: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495 locks held by getty/5398: 2, last CPU#1: #0: ffff888033f5a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000323b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211 locks held by udevd/5641: 1, last CPU#1: #0: ffff88802871f350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990 locks held by kworker/0:3/5729: 2, on CPU#0: #0: ffff8880597a1d50 ((wq_completion)wg-crypt-wg0#12){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff8880597a1d50 ((wq_completion)wg-crypt-wg0#12){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff8880597a1d50 ((wq_completion)wg-crypt-wg0#12){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline] #0: ffff8880597a1d50 ((wq_completion)wg-crypt-wg0#12){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594 #1: ffffc90004367c40 ((work_completion)(&({ do { const void __attribute__((btf_type_tag("percpu"))) *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc90004367c40 ((work_completion)(&({ do { const void __attribute__((btf_type_tag("percpu"))) *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc90004367c40 ((work_completion)(&({ do { const void __attribute__((btf_type_tag("percpu"))) *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline] #1: ffffc90004367c40 ((work_completion)(&({ do { const void __attribute__((btf_type_tag("percpu"))) *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594 locks held by kworker/u8:21/5972: 2, last CPU#1: #0: ffff88813feac150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff88813feac150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff88813feac150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline] #0: ffff88813feac150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594 #1: ffffc9000505fc40 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc9000505fc40 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc9000505fc40 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline] #1: ffffc9000505fc40 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594 locks held by kworker/0:7/14531: 6, on CPU#0: #0: ffff88807b92fd50 ((wq_completion)wg-crypt-wg1#12){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffff88807b92fd50 ((wq_completion)wg-crypt-wg1#12){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffff88807b92fd50 ((wq_completion)wg-crypt-wg1#12){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline] #0: ffff88807b92fd50 ((wq_completion)wg-crypt-wg1#12){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594 #1: ffffc90003d07c40 ((work_completion)(&({ do { const void __attribute__((btf_type_tag("percpu"))) *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #1: ffffc90003d07c40 ((work_completion)(&({ do { const void __attribute__((btf_type_tag("percpu"))) *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffc90003d07c40 ((work_completion)(&({ do { const void __attribute__((btf_type_tag("percpu"))) *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline] #1: ffffc90003d07c40 ((work_completion)(&({ do { const void __attribute__((btf_type_tag("percpu"))) *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ((typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))))((unsigned long)((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))) + (((__per_cpu_offset[(cpu)]))))); })->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594 #2: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: local_lock_acquire include/linux/local_lock_internal.h:46 [inline] #2: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: process_backlog+0x3de/0x18b0 net/core/dev.c:6897 #3: ffffffff9c1c3c08 (&____s->seqcount#2){----}-{0:0}, at: ktime_get_real_ts64+0x45/0x2d0 kernel/time/timekeeping.c:985 #4: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #4: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #4: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: nf_hook include/linux/netfilter.h:249 [inline] #4: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: NF_HOOK+0x9e/0x3c0 include/linux/netfilter.h:323 #5: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #5: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #5: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline] #5: ffffffff9035ad60 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495 locks held by syz.4.2634/14717: 1, last CPU#1: #0: ffff88802871f350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x294/0x480 block/bdev.c:1378 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66 trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:377 [inline] watchdog+0x1073/0x10f0 kernel/hung_task.c:598 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 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5976 Comm: kworker/u8:25 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026 RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:229 [inline] RIP: 0010:unwind_next_frame+0x229/0x2550 arch/x86/kernel/unwind_orc.c:510 Code: 00 00 45 8b 6d 00 44 89 f8 ff c0 4c 8d 24 85 90 89 30 93 4c 89 e0 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 66 1d 00 00 45 8b 04 24 <41> ff c0 4a 8d 04 6d 00 00 00 00 4c 01 e8 48 8d 34 45 98 22 73 92 RSP: 0018:ffffc90000006aa0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 8000000000000100 RDX: 00000000000b2bf4 RSI: ffffffff8cb02a60 RDI: ffffffff8cb02a20 RBP: ffffffff81b41b48 R08: 00000000000251ab R09: 0000000000000000 R10: ffffc90000006b98 R11: ffffffff81b41bb0 R12: ffffffff93335a00 R13: 00000000000251a0 R14: ffffc90000006b48 R15: 000000000000b41b FS: 0000000000000000(0000) GS:ffff888123135000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffceba33cb8 CR3: 0000000010148000 CR4: 00000000003526f0 Call Trace: arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3f/0x90 mm/kasan/common.c:79 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:599 poison_slab_object mm/kasan/common.c:267 [inline] __kasan_slab_free+0x70/0x90 mm/kasan/common.c:299 kasan_slab_free include/linux/kasan.h:239 [inline] slab_free_hook mm/slub.c:2780 [inline] slab_free mm/slub.c:6615 [inline] kmem_cache_free+0x184/0x660 mm/slub.c:6742 skb_ext_reset include/linux/skbuff.h:5152 [inline] skb_release_head_state+0x274/0x370 net/core/skbuff.c:1182 skb_release_all net/core/skbuff.c:1188 [inline] __kfree_skb+0x24/0x210 net/core/skbuff.c:1204 kfree_skb_reason include/linux/skbuff.h:1334 [inline] kfree_skb include/linux/skbuff.h:1343 [inline] ip6_mc_input+0x878/0xc80 net/ipv6/ip6_input.c:639 ip_sabotage_in+0x1e1/0x270 net/bridge/br_netfilter_hooks.c:989 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:633 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:323 __netif_receive_skb_one_core net/core/dev.c:6437 [inline] __netif_receive_skb net/core/dev.c:6550 [inline] netif_receive_skb_internal net/core/dev.c:6636 [inline] netif_receive_skb+0x278/0xbf0 net/core/dev.c:6695 NF_HOOK+0xa4/0x3a0 include/linux/netfilter.h:325 br_handle_frame_finish+0x1219/0x1ae0 net/bridge/br_input.c:237 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:325 [inline] br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_bridge_pre net/bridge/br_input.c:293 [inline] br_handle_frame+0x1329/0x1600 net/bridge/br_input.c:453 __netif_receive_skb_core+0x989/0x30f0 net/core/dev.c:6316 __netif_receive_skb_one_core net/core/dev.c:6435 [inline] __netif_receive_skb net/core/dev.c:6550 [inline] process_backlog+0x727/0x18b0 net/core/dev.c:6901 __napi_poll+0xaa/0x330 net/core/dev.c:7987 napi_poll net/core/dev.c:8050 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8207 handle_softirqs+0x265/0x8d0 kernel/softirq.c:669 __do_softirq kernel/softirq.c:703 [inline] invoke_softirq kernel/softirq.c:542 [inline] __irq_exit_rcu+0xc6/0x220 kernel/softirq.c:786 irq_exit_rcu+0x9/0x30 kernel/softirq.c:809 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:710 RIP: 0010:__raw_write_unlock_irq include/linux/rwlock_api_smp.h:302 [inline] RIP: 0010:_raw_write_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:393 Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8a e9 79 f5 48 89 df e8 b2 68 7a f5 e8 4d 27 a7 f5 fb bf 01 00 00 00 e2 49 6b f5 65 48 8b 05 5a f0 e3 08 48 85 c0 74 07 5b c3 cc cc RSP: 0018:ffffc900050efb50 EFLAGS: 00000206 RAX: 00000000000003e1 RBX: ffffffff9000a040 RCX: 8000000000000001 RDX: 0000000000000000 RSI: ffffffff8e9f856c RDI: 0000000000000001 RBP: ffffc900050efcd0 R08: ffffffff91e196bf R09: 1ffffffff23c32d7 R10: dffffc0000000000 R11: fffffbfff23c32d8 R12: ffff88802d683e80 R13: 0000000000000000 R14: ffff888030a19bc0 R15: ffff8880287b4150 release_task+0x1206/0x1730 kernel/exit.c:291 exit_notify kernel/exit.c:781 [inline] do_exit+0x1667/0x2360 kernel/exit.c:992 kthread+0x3a9/0x480 kernel/kthread.c:438 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245