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: 240d, last: 4h54m
▶ ▼ Similar bugs (18)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: task hung in rtnetlink_rcv_msg (2) 1 4 8d10h 125d 0/2 upstream: reported on 2026/05/16 14:21
linux-5.15 INFO: task hung in rtnetlink_rcv_msg 1 1 1162d 1162d 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 1704d 1884d 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 1317d 1551d 0/1 upstream: reported on 2022/06/20 23:55
linux-4.19 INFO: task hung in rtnetlink_rcv_msg 1 11 2136d 2458d 0/1 auto-closed as invalid on 2021/03/12 19:03
upstream INFO: task hung in rtnetlink_rcv_msg (2) net 1 syz, C inconclusive 548 543d 752d 0/29 closed as invalid on 2025/04/18 16:40
linux-5.15 INFO: task hung in rtnetlink_rcv_msg (4) origin:upstream 1 syz 4 23d 167d 0/3 upstream: reported syz repro on 2026/04/05 04:20
linux-6.1 INFO: task hung in rtnetlink_rcv_msg (3) origin:upstream 1 syz, C error 24 10d 729d 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 520d 520d 0/3 auto-obsoleted due to no activity on 2025/07/26 04:34
upstream INFO: task hung in rtnetlink_rcv_msg net 1 syz, C inconclusive inconclusive 1970 802d 2765d 26/29 fixed on 2024/07/09 19:14
linux-4.14 INFO: task hung in rtnetlink_rcv_msg 1 1 1297d 1297d 0/1 upstream: reported on 2023/03/01 21:15
linux-5.15 INFO: task hung in rtnetlink_rcv_msg (2) 1 70 672d 964d 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 802d 966d 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 1087d 1087d 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 309d 455d 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 3 228d 320d 0/2 auto-obsoleted due to no activity on 2026/05/14 04:07
upstream INFO: task hung in rtnetlink_rcv_msg (3) net 1 4 470d 511d 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 1726d 1832d 0/29 closed as invalid on 2022/02/08 10:22

Sample crash report:
INFO: task syz-executor:1975 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:1975  tgid:1975  ppid:1      flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6063 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7883
 __schedule_loop kernel/sched/core.c:7960 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7975
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8032
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x902/0x1b90 kernel/locking/mutex.c:806
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136
 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:6676
 netlink_rcv_skb+0x24d/0x4e0 net/netlink/af_netlink.c:2549
 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6697
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x8bf/0xa70 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x7d1/0xad0 net/netlink/af_netlink.c:1890
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg net/socket.c:727 [inline]
 __sys_sendto+0x663/0x6e0 net/socket.c:2197
 __do_sys_sendto net/socket.c:2204 [inline]
 __se_sys_sendto net/socket.c:2200 [inline]
 __x64_sys_sendto+0xe9/0x100 net/socket.c:2200
 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f3c8c9592d7
RSP: 002b:00007ffdd9c76320 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555571405500 RCX: 00007f3c8c9592d7
RDX: 0000000000000028 RSI: 00007f3c8d754670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffdd9c76384 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f3c8d754670 R15: 0000000000000000
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 2db523747cf1beec8353ecf3fbcf651dac8dc83d
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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:114
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:63
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 cpumask_backtrace+0x1f/0x30 lib/nmi_backtrace.c:127
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xe45/0xf90 kernel/hung_task.c:423
 kthread+0x2c4/0x360 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: 310 Comm: kworker/0:2 Not tainted syzkaller #0 2db523747cf1beec8353ecf3fbcf651dac8dc83d
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: mld mld_query_work
RIP: 0010:stackdepot_memcmp lib/stackdepot.c:528 [inline]
RIP: 0010:find_stack lib/stackdepot.c:561 [inline]
RIP: 0010:stack_depot_save_flags+0x19b/0x800 lib/stackdepot.c:618
Code: 7d 4c 8b 2c 08 49 39 d5 0f 84 80 00 00 00 45 89 d7 eb 09 4d 8b 6d 00 49 39 d5 74 72 45 39 65 10 75 f1 45 39 55 14 75 eb 31 c0 <49> 8b 0c c6 49 3b 4c c5 20 75 de 48 ff c0 41 39 c7 75 ed 83 fe 02
RSP: 0018:ffffc90000007380 EFLAGS: 00000202
RAX: 0000000000000010 RBX: 0000000000000000 RCX: ffffffff8485aaac
RDX: ffff8881f558c180 RSI: 0000000000000001 RDI: 0000000080aa6a30
RBP: ffffc900000073e0 R08: 000000003756672f R09: 000000006e4c325e
R10: 0000000000000012 R11: ffffffff8175a7a0 R12: 000000004c738c18
R13: ffff88811dd962b0 R14: ffffc900000073f0 R15: 0000000000000012
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f57a9a347a6 CR3: 000000010c384000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000071 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 kasan_save_stack mm/kasan/common.c:50 [inline]
 kasan_save_track+0x4f/0x80 mm/kasan/common.c:70
 kasan_save_free_info+0x44/0x50 mm/kasan/generic.c:579
 poison_slab_object mm/kasan/common.c:249 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:266
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2445 [inline]
 slab_free mm/slub.c:4714 [inline]
 kmem_cache_free+0x1bd/0x4f0 mm/slub.c:4825
 kfree_skbmem net/core/skbuff.c:-1 [inline]
 __kfree_skb+0x18f/0x210 net/core/skbuff.c:1205
 sk_skb_reason_drop+0xd8/0x310 net/core/skbuff.c:1242
 kfree_skb_reason include/linux/skbuff.h:1303 [inline]
 kfree_skb include/linux/skbuff.h:1312 [inline]
 igmp6_event_query+0x23b/0x2e0 net/ipv6/mcast.c:1390
 icmpv6_rcv+0xf11/0x17d0 net/ipv6/icmp.c:1006
 ip6_protocol_deliver_rcu+0xbc0/0x1270 net/ipv6/ip6_input.c:436
 ip6_input_finish net/ipv6/ip6_input.c:481 [inline]
 NF_HOOK include/linux/netfilter.h:317 [inline]
 ip6_input+0x1c3/0x3a0 net/ipv6/ip6_input.c:490
 ip6_mc_input+0x333/0x680 net/ipv6/ip6_input.c:584
 dst_input include/net/dst.h:469 [inline]
 ip6_rcv_finish+0x341/0x3c0 net/ipv6/ip6_input.c:79
 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:5801 [inline]
 __netif_receive_skb net/core/dev.c:5914 [inline]
 process_backlog+0x472/0xaf0 net/core/dev.c:6250
 __napi_poll+0xcd/0x600 net/core/dev.c:6901
 napi_poll net/core/dev.c:6970 [inline]
 net_rx_action+0x5dc/0xd70 net/core/dev.c:7092
 handle_softirqs+0x1aa/0x620 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]
 mld_query_work+0xb25/0x2e20 net/ipv6/mcast.c:1528
 process_one_work kernel/workqueue.c:3273 [inline]
 process_scheduled_works+0x7f4/0x1060 kernel/workqueue.c:3354
 worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
 kthread+0x2c4/0x360 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 (245):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/19 03:36 android16-6.12 fb15c16e04b2 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/09/18 17:52 android16-6.12 17176090d7cd 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/09/18 11:25 android16-6.12 17176090d7cd 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/09/10 21:33 android16-6.12 de3d34623482 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/09/08 15:40 android16-6.12 136b3cf43ec1 243b72f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/09/03 11:09 android16-6.12 8473ff8a565c 6a988719 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/09/03 01:37 android16-6.12 58b61a547e48 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/31 16:20 android16-6.12 96b3287eace8 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/31 06:20 android16-6.12 96b3287eace8 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/30 23:11 android16-6.12 36bee94a7cf9 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/26 20:36 android16-6.12 7ee04de323f7 a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/24 11:46 android16-6.12 e8c85685a629 b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/22 10:02 android16-6.12 e8c85685a629 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/20 22:18 android16-6.12 11fb45c3d713 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/20 19:04 android16-6.12 7aa7a88586d9 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/17 05:10 android16-6.12 26014f6c6077 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/16 10:08 android16-6.12 26014f6c6077 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/15 10:06 android16-6.12 26014f6c6077 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/14 17:54 android16-6.12 c3360dde0a9e 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/12 03:44 android16-6.12 0db85ff78f60 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/10 01:29 android16-6.12 309759bcbe6d 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/09 17:06 android16-6.12 309759bcbe6d 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/07 16:16 android16-6.12 282da3f968e5 e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/07 01:19 android16-6.12 749a6f9d41aa c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/05 13:20 android16-6.12 f068f96e8cc3 52aa2820 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/04 12:35 android16-6.12 4f986595e48e 9451e17e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/04 02:45 android16-6.12 4f986595e48e 9451e17e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/03 02:08 android16-6.12 1a138e24e292 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/01 17:09 android16-6.12 1a138e24e292 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/08/01 13:16 android16-6.12 1a138e24e292 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/30 21:18 android16-6.12 f1c9c21d1c2f aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/29 19:47 android16-6.12 f1c9c21d1c2f 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/26 17:26 android16-6.12 579215f16d4e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/26 12:11 android16-6.12 579215f16d4e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/24 00:35 android16-6.12 629d76c0f948 544adce9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/22 03:30 android16-6.12 c2f8d5c68db2 b561ce9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/21 22:45 android16-6.12 c2f8d5c68db2 b561ce9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/21 21:09 android16-6.12 c2f8d5c68db2 7c5de9c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/21 10:15 android16-6.12 5aeb3ef16d03 7c5de9c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/20 00:55 android16-6.12 0fd55a309793 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/18 12:01 android16-6.12 0fd55a309793 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/16 21:15 android16-6.12 57c0ba8fb2f8 71b49442 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/16 06:00 android16-6.12 c6f9cfff7e53 27a8bd60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/15 21:11 android16-6.12 a123382dbca7 a4ed0f4f .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/15 17:51 android16-6.12 a123382dbca7 a4ed0f4f .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/14 17:35 android16-6.12 5dd528d5e93a 2130f682 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/07/12 16:19 android16-6.12 0026e4ecedf0 d78ea535 .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.