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INFO: task hung in rtnetlink_rcv_msg (2)

Status: premoderation: reported on 2026/01/21 16:59
Reported-by: syzbot+c8594a8ad43127762feb@syzkaller.appspotmail.com
First crash: 2d22h, last: 2d22h
▶ ▼ Similar bugs (16)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in rtnetlink_rcv_msg 1 1 924d 924d 0/3 auto-obsoleted due to no activity on 2023/10/22 21:13
linux-4.19 INFO: task hung in rtnetlink_rcv_msg (2) 1 14 1467d 1646d 0/1 auto-closed as invalid on 2022/05/18 11:30
linux-4.19 INFO: task hung in rtnetlink_rcv_msg (3) 1 8 1079d 1313d 0/1 upstream: reported on 2022/06/20 23:55
linux-4.19 INFO: task hung in rtnetlink_rcv_msg 1 11 1898d 2220d 0/1 auto-closed as invalid on 2021/03/12 19:03
upstream INFO: task hung in rtnetlink_rcv_msg (2) net 1 C inconclusive 548 306d 514d 0/29 closed as invalid on 2025/04/18 16:40
linux-6.1 INFO: task hung in rtnetlink_rcv_msg (3) origin:upstream 1 C error 20 13d 492d 0/3 upstream: reported C repro on 2024/09/19 14:16
linux-5.15 INFO: task hung in rtnetlink_rcv_msg (3) 1 1 282d 282d 0/3 auto-obsoleted due to no activity on 2025/07/26 04:34
upstream INFO: task hung in rtnetlink_rcv_msg net 1 C inconclusive inconclusive 1970 564d 2527d 26/29 fixed on 2024/07/09 19:14
linux-4.14 INFO: task hung in rtnetlink_rcv_msg 1 1 1059d 1059d 0/1 upstream: reported on 2023/03/01 21:15
linux-5.15 INFO: task hung in rtnetlink_rcv_msg (2) 1 70 435d 726d 0/3 auto-obsoleted due to no activity on 2025/01/24 13:11
linux-6.1 INFO: task hung in rtnetlink_rcv_msg (2) 1 67 564d 728d 0/3 auto-obsoleted due to no activity on 2024/09/17 07:45
linux-6.1 INFO: task hung in rtnetlink_rcv_msg 1 1 849d 849d 0/3 auto-obsoleted due to no activity on 2024/01/09 18:18
android-6-12 INFO: task hung in rtnetlink_rcv_msg 1 265 71d 217d 0/1 auto-obsoleted due to no activity on 2026/01/02 16:22
linux-6.6 INFO: task hung in rtnetlink_rcv_msg 1 2 56d 83d 0/2 upstream: reported on 2025/11/02 14:58
upstream INFO: task hung in rtnetlink_rcv_msg (3) net 1 4 232d 273d 0/29 auto-obsoleted due to no activity on 2025/09/03 19:16
upstream INFO: task hung in cangw_pernet_exit (3) can 1 syz unreliable 290 1488d 1594d 0/29 closed as invalid on 2022/02/08 10:22

Sample crash report:
INFO: task syz-executor:3753 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:3753  tgid:3753  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x1528/0x1fb0 kernel/sched/core.c:7846
 __schedule_loop kernel/sched/core.c:7927 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7942
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7999
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 rtnl_lock net/core/rtnetlink.c:79 [inline]
 rtnetlink_rcv_msg+0x79e/0xa40 net/core/rtnetlink.c:6672
 netlink_rcv_skb+0x256/0x4f0 net/netlink/af_netlink.c:2545
 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6693
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x8c0/0xa60 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x7fe/0xb10 net/netlink/af_netlink.c:1889
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x715/0x790 net/socket.c:2217
 __do_sys_sendto net/socket.c:2229 [inline]
 __se_sys_sendto net/socket.c:2225 [inline]
 __x64_sys_sendto+0xe9/0x100 net/socket.c:2225
 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f5efe955ed7
RSP: 002b:00007ffdb8bcaf60 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555572d3e500 RCX: 00007f5efe955ed7
RDX: 000000000000002c RSI: 00007f5eff744670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffdb8bcafc4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f5eff744670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:3755 blocked for more than 125 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:3755  tgid:3755  ppid:1      flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x1528/0x1fb0 kernel/sched/core.c:7846
 __schedule_loop kernel/sched/core.c:7927 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7942
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7999
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 rtnl_lock net/core/rtnetlink.c:79 [inline]
 rtnetlink_rcv_msg+0x79e/0xa40 net/core/rtnetlink.c:6672
 netlink_rcv_skb+0x256/0x4f0 net/netlink/af_netlink.c:2545
 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6693
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x8c0/0xa60 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x7fe/0xb10 net/netlink/af_netlink.c:1889
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x715/0x790 net/socket.c:2217
 __do_sys_sendto net/socket.c:2229 [inline]
 __se_sys_sendto net/socket.c:2225 [inline]
 __x64_sys_sendto+0xe9/0x100 net/socket.c:2225
 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f6532755ed7
RSP: 002b:00007ffcf00981c0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000055558ac09500 RCX: 00007f6532755ed7
RDX: 000000000000002c RSI: 00007f6533544670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffcf0098224 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f6533544670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:3759 blocked for more than 125 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:3759  tgid:3759  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x1528/0x1fb0 kernel/sched/core.c:7846
 __schedule_loop kernel/sched/core.c:7927 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7942
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7999
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 rtnl_lock net/core/rtnetlink.c:79 [inline]
 rtnetlink_rcv_msg+0x79e/0xa40 net/core/rtnetlink.c:6672
 netlink_rcv_skb+0x256/0x4f0 net/netlink/af_netlink.c:2545
 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6693
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x8c0/0xa60 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x7fe/0xb10 net/netlink/af_netlink.c:1889
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x715/0x790 net/socket.c:2217
 __do_sys_sendto net/socket.c:2229 [inline]
 __se_sys_sendto net/socket.c:2225 [inline]
 __x64_sys_sendto+0xe9/0x100 net/socket.c:2225
 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fd59a355ed7
RSP: 002b:00007ffeeb68c1e0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000055557d915500 RCX: 00007fd59a355ed7
RDX: 0000000000000028 RSI: 00007fd59b144670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffeeb68c244 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fd59b144670 R15: 0000000000000000
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 bfede744b46277b76d69ebe6cb8c22209d769bcb
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2ba/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xdad/0xf00 kernel/hung_task.c:423
 kthread+0x2c9/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 672 Comm: kworker/0:4 Not tainted syzkaller #0 bfede744b46277b76d69ebe6cb8c22209d769bcb
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: wg-crypt-wg1 wg_packet_decrypt_worker
RIP: 0010:__find_rr_leaf+0x23e/0x840 net/ipv6/route.c:869
Code: 80 3c 04 00 74 08 4c 89 ef e8 0e 4b e9 fc 49 83 7d 00 00 0f 85 3a 01 00 00 4d 8d a6 c0 00 00 00 4c 89 e7 44 89 fe 8b 54 24 34 <8b> 4d 10 4c 8b 45 20 4c 8b 4d 18 e8 62 07 00 00 84 c0 0f 84 b2 00
RSP: 0018:ffffc90000006d00 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: 1ffff1102166340c RCX: ffff88811c070000
RDX: 000000000000000d RSI: 0000000000000001 RDI: ffff88810b31a0c0
RBP: ffffc90000006e58 R08: ffffc90000006f80 R09: ffffc90000006f90
R10: ffffc900000070f0 R11: fffff52000000e22 R12: ffff88810b31a0c0
R13: ffff88810b31a0b0 R14: ffff88810b31a000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f761a85b467 CR3: 000000010cb2c000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 find_rr_leaf net/ipv6/route.c:890 [inline]
 rt6_select net/ipv6/route.c:934 [inline]
 fib6_table_lookup+0x2ee/0x9e0 net/ipv6/route.c:2230
 ip6_pol_route+0x17a/0x1340 net/ipv6/route.c:2266
 ip6_pol_route_input+0x5a/0x80 net/ipv6/route.c:2323
 pol_lookup_func include/net/ip6_fib.h:626 [inline]
 fib6_rule_lookup+0x4ee/0x6d0 net/ipv6/fib6_rules.c:117
 ip6_route_input_lookup net/ipv6/route.c:2335 [inline]
 ip6_route_input+0x62e/0x8f0 net/ipv6/route.c:2631
 ip6_rcv_finish_core net/ipv6/ip6_input.c:66 [inline]
 ip6_rcv_finish+0x15a/0x3e0 net/ipv6/ip6_input.c:77
 NF_HOOK include/linux/netfilter.h:317 [inline]
 ipv6_rcv+0xf1/0x240 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core net/core/dev.c:5763 [inline]
 __netif_receive_skb net/core/dev.c:5876 [inline]
 netif_receive_skb_internal net/core/dev.c:5962 [inline]
 netif_receive_skb+0x147/0x7b0 net/core/dev.c:6021
 br_netif_receive_skb net/bridge/br_input.c:30 [inline]
 NF_HOOK include/linux/netfilter.h:317 [inline]
 br_pass_frame_up+0x126/0x1b0 net/bridge/br_input.c:70
 br_handle_frame_finish+0x1317/0x1760 net/bridge/br_input.c:221
 nf_hook_bridge_pre net/bridge/br_input.c:301 [inline]
 br_handle_frame+0x5a6/0xba0 net/bridge/br_input.c:424
 __netif_receive_skb_core+0xfa8/0x3a90 net/core/dev.c:5657
 __netif_receive_skb_one_core net/core/dev.c:5761 [inline]
 __netif_receive_skb net/core/dev.c:5876 [inline]
 process_backlog+0x3e5/0xad0 net/core/dev.c:6212
 __napi_poll+0xd0/0x610 net/core/dev.c:6863
 napi_poll net/core/dev.c:6932 [inline]
 net_rx_action+0x5ea/0xd80 net/core/dev.c:7054
 handle_softirqs+0x1aa/0x630 kernel/softirq.c:621
 __do_softirq+0xf/0x16 kernel/softirq.c:659
 do_softirq+0xb8/0x110 kernel/softirq.c:503
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock_bh+0x54/0x60 kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline]
 wg_packet_decrypt_worker+0xcde/0xd50 drivers/net/wireguard/receive.c:499
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400
 kthread+0x2c9/0x370 kernel/kthread.c:389
 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/21 16:59 android16-6.12 f33ca06267f8 8fc37797 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
* Struck through repros no longer work on HEAD.