INFO: task dhcpcd:5488 blocked for more than 145 seconds. Not tainted 6.14.0-syzkaller-00826-g327ecdbc0fda #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:dhcpcd state:D stack:23256 pid:5488 tgid:5488 ppid:5487 task_flags:0x400140 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5367 [inline] __schedule+0x112e/0x5b80 kernel/sched/core.c:6748 __schedule_loop kernel/sched/core.c:6825 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6840 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6897 __mutex_lock_common kernel/locking/mutex.c:664 [inline] __mutex_lock+0x6bd/0xb10 kernel/locking/mutex.c:732 rtnl_net_lock include/linux/rtnetlink.h:129 [inline] inet_rtm_newaddr+0x316/0x1560 net/ipv4/devinet.c:987 rtnetlink_rcv_msg+0x95b/0xea0 net/core/rtnetlink.c:6912 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2533 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline] netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1338 netlink_sendmsg+0x8cb/0xd70 net/netlink/af_netlink.c:1882 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:733 [inline] ____sys_sendmsg+0xa87/0xc70 net/socket.c:2573 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2627 __sys_sendmsg+0x16e/0x220 net/socket.c:2659 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: 0033:0x7f5829064a4b RSP: 002b:00007ffe763f70a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f5828f8c6c0 RCX: 00007f5829064a4b RDX: 0000000000000000 RSI: 00007ffe7640b258 RDI: 000000000000003e RBP: 000000000000003e R08: 0000000000000000 R09: 00007ffe7640b258 R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff R13: 00007ffe7640b258 R14: 0000000000000044 R15: 0000000000000001 Showing all locks held in the system: 1 lock held by kthreadd/2: 3 locks held by kworker/0:1/10: #0: ffff88801b078d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213 #1: ffffc900000f7d18 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214 #2: ffffffff8fef7828 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 3 locks held by kworker/u8:0/12: 3 locks held by kworker/u8:1/13: 1 lock held by khungtaskd/31: #0: ffffffff8e1be500 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e1be500 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e1be500 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6761 3 locks held by kworker/u8:2/36: 3 locks held by kworker/u8:3/53: 3 locks held by kworker/u8:4/63: 3 locks held by kswapd0/90: 3 locks held by kworker/u8:5/1152: 2 locks held by kworker/R-bat_e/3394: 3 locks held by kworker/u8:6/3644: 3 locks held by kworker/u8:7/3682: 4 locks held by kworker/u8:8/3728: 2 locks held by syslogd/5176: 2 locks held by udevd/5194: 1 lock held by dhcpcd/5488: #0: ffffffff8fef7828 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:129 [inline] #0: ffffffff8fef7828 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x316/0x1560 net/ipv4/devinet.c:987 2 locks held by getty/5581: #0: ffff88814d6bc0a0 (&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/5806: 3 locks held by kworker/0:3/5818: 4 locks held by kworker/1:3/5867: 3 locks held by kworker/u8:9/6129: #0: ffff88814d272148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213 #1: ffffc9000afffd18 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214 #2: ffffffff8fef7828 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:129 [inline] #2: ffffffff8fef7828 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4730 3 locks held by kworker/u8:10/6219: 3 locks held by kworker/u8:11/6672: 4 locks held by syz-executor/6805: 2 locks held by syz-executor/7032: 3 locks held by kworker/u8:12/7385: 1 lock held by syz-executor/8922: 6 locks held by syz.3.1238/12400: 2 locks held by syz-executor/12481: 3 locks held by kworker/u8:13/12508: 2 locks held by kworker/0:4/12510: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.14.0-syzkaller-00826-g327ecdbc0fda #0 PREEMPT(full) 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:158 [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: 5867 Comm: kworker/1:3 Not tainted 6.14.0-syzkaller-00826-g327ecdbc0fda #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_power_efficient neigh_periodic_work RIP: 0010:stack_trace_save+0x38/0xd0 kernel/stacktrace.c:114 Code: 53 89 f6 31 c9 48 83 c4 80 48 89 e3 48 c7 04 24 b3 8a b5 41 48 c7 44 24 08 0d bb 98 8d 48 c1 eb 03 48 c7 44 24 10 20 36 a6 81 <48> 01 c3 c7 03 f1 f1 f1 f1 c7 43 04 00 00 00 f3 c7 43 08 f3 f3 f3 RSP: 0018:ffffc90000a07bc8 EFLAGS: 00000a02 RAX: dffffc0000000000 RBX: 1ffff92000140f79 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000040 RDI: ffffc90000a07c58 RBP: 0000000000000000 R08: 0000000000000100 R09: 0000000000000000 R10: ffffed103dc61100 R11: 0000000000000005 R12: 0000000000000001 R13: 0000000000212110 R14: ffffea0007b8c200 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055556f7ba5c8 CR3: 000000002b05e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: 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:2376 [inline] slab_free mm/slub.c:4633 [inline] kmem_cache_free+0x2e2/0x4d0 mm/slub.c:4735 __skb_ext_put+0x102/0x2c0 net/core/skbuff.c:7011 skb_ext_put include/linux/skbuff.h:4876 [inline] skb_ext_put include/linux/skbuff.h:4873 [inline] skb_release_head_state+0x1c2/0x290 net/core/skbuff.c:1092 skb_release_all net/core/skbuff.c:1098 [inline] __kfree_skb net/core/skbuff.c:1114 [inline] sk_skb_reason_drop+0xeb/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 neigh_periodic_work+0x767/0xcb0 net/core/neighbour.c:968 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