INFO: task syz.1.3093:12413 blocked for more than 147 seconds. Not tainted 6.14.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.3093 state:D stack:27728 pid:12413 tgid:12409 ppid:5828 task_flags:0x400040 flags:0x00004006 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_preempt_disabled+0x13/0x30 kernel/sched/core.c:6914 __mutex_lock_common kernel/locking/mutex.c:662 [inline] __mutex_lock+0x6bd/0xb10 kernel/locking/mutex.c:730 tty_open_by_driver drivers/tty/tty_io.c:2046 [inline] tty_open+0x53d/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: 0033:0x7f7b5bb8bad0 RSP: 002b:00007f7b5c98ab70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f7b5bb8bad0 RDX: 0000000000000002 RSI: 00007f7b5c98ac10 RDI: 00000000ffffff9c RBP: 00007f7b5c98ac10 R08: 0000000000000000 R09: 00007f7b5c98a987 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f7b5bda5fa0 R15: 00007ffed0a5d6f8 Showing all locks held in the system: 2 locks held by kworker/u8:1/13: 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 3 locks held by kworker/1:1/52: 7 locks held by kworker/u8:3/54: 1 lock held by kswapd0/90: 3 locks held by syslogd/5176: 2 locks held by dhcpcd/5487: 2 locks held by getty/5579: #0: ffff88814d75e0a0 (&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 4 locks held by syz-executor/5816: 2 locks held by syz-executor/5818: 1 lock held by syz-executor/5820: 1 lock held by syz-executor/5826: 2 locks held by kworker/1:3/5831: 1 lock held by syz.1.3093/12413: #0: ffffffff8ee888e8 (tty_mutex){+.+.}-{4:4}, at: tty_open_by_driver drivers/tty/tty_io.c:2046 [inline] #0: ffffffff8ee888e8 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x53d/0xf80 drivers/tty/tty_io.c:2129 2 locks held by kworker/u8:0/12415: 3 locks held by kworker/u8:9/12417: 3 locks held by kworker/u8:10/12420: 1 lock held by syz-executor/12421: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.14.0-rc7-syzkaller #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: 54 Comm: kworker/u8:3 Not tainted 6.14.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:unwind_next_frame+0xb1/0x20c0 arch/x86/kernel/unwind_orc.c:482 Code: b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 ac 17 00 00 49 8b 45 38 bf 01 00 00 00 48 89 44 24 10 e8 2f 22 1f 00 <4d> 8d 65 50 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 80 RSP: 0018:ffffc90000a27b08 EFLAGS: 00000293 RAX: 0000000000000103 RBX: 0000000000000002 RCX: 1ffffffff3518314 RDX: 0000000000000000 RSI: ffffffff8a001abe RDI: 0000000000000001 RBP: ffffc90000a27bc0 R08: ffffc90000a27bac R09: ffffffff918a65fc R10: ffffc90000a27b78 R11: 00000000000878f9 R12: ffffffff81a5ad30 R13: ffffc90000a27b78 R14: 0000000000000000 R15: ffff888020ab8000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f79dc789ff8 CR3: 00000000675dc000 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 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4609 [inline] kmem_cache_free+0x2e2/0x4d0 mm/slub.c:4711 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1058 __kfree_skb net/core/skbuff.c:1115 [inline] sk_skb_reason_drop+0x136/0x1a0 net/core/skbuff.c:1152 kfree_skb_reason include/linux/skbuff.h:1271 [inline] kfree_skb include/linux/skbuff.h:1280 [inline] ip6_mc_input+0x7af/0xfd0 net/ipv6/ip6_input.c:591 dst_input include/net/dst.h:469 [inline] dst_input include/net/dst.h:467 [inline] ip6_rcv_finish+0x3a2/0x5b0 net/ipv6/ip6_input.c:79 ip_sabotage_in+0x21b/0x290 net/bridge/br_netfilter_hooks.c:993 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626 nf_hook.constprop.0+0x42e/0x750 include/linux/netfilter.h:269 NF_HOOK include/linux/netfilter.h:312 [inline] ipv6_rcv+0xa4/0x680 net/ipv6/ip6_input.c:309 __netif_receive_skb_one_core+0x12e/0x1e0 net/core/dev.c:5896 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6009 netif_receive_skb_internal net/core/dev.c:6095 [inline] netif_receive_skb+0x13f/0x7b0 net/core/dev.c:6154 NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] br_pass_frame_up+0x346/0x490 net/bridge/br_input.c:70 br_handle_frame_finish+0xecc/0x1c90 net/bridge/br_input.c:226 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] 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: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