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INFO: task hung in addrconf_dad_work

Status: upstream: reported C repro on 2025/11/26 06:47
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+4bfb583ae9cc4f93097e@syzkaller.appspotmail.com
First crash: 217d, last: 19d
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2026/05/30 linux-6.6.y (ToT) 0a40c6fbd105 C [report] INFO: task hung in corrupted
2026/04/08 upstream (ToT) 3036cd0d3328 C [report] INFO: task hung in corrupted
2026/05/30 upstream (ToT) f5e5d3509bff C Didn't crash
▶ ▼ Similar bugs (15)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in addrconf_dad_work (2) 1 67 651d 857d 0/3 auto-obsoleted due to no activity on 2024/11/26 11:15
android-414 INFO: task hung in addrconf_dad_work 1 1 2578d 2578d 0/1 auto-closed as invalid on 2019/10/25 08:37
upstream INFO: task hung in addrconf_dad_work (5) prio:normal netfilter 1 C done 1759 1h22m 701d 0/29 upstream: reported C repro on 2024/07/29 15:23
android-49 INFO: task hung in addrconf_dad_work 1 1 2865d 2865d 0/3 auto-closed as invalid on 2019/02/22 20:09
upstream INFO: task hung in addrconf_dad_work (2) net 1 C unreliable error 107 951d 1306d 0/29 closed as invalid on 2023/11/23 17:05
linux-6.1 INFO: task hung in addrconf_dad_work (4) missing-backport origin:lts-only 1 C error 8 50d 398d 0/3 upstream: reported C repro on 2025/05/29 09:13
linux-6.1 INFO: task hung in addrconf_dad_work 1 2 1140d 1170d 0/3 auto-obsoleted due to no activity on 2023/08/26 05:16
upstream INFO: task hung in addrconf_dad_work net 1 C inconclusive inconclusive 468 1651d 2691d 0/29 closed as invalid on 2022/02/08 10:54
linux-5.15 INFO: task hung in addrconf_dad_work origin:upstream 1 C error 132 59d 893d 0/3 upstream: reported C repro on 2024/01/20 08:09
upstream INFO: task hung in addrconf_dad_work (3) net 1 C 185 841d 882d 25/29 fixed on 2024/03/25 23:45
linux-6.1 INFO: task hung in addrconf_dad_work (3) 1 2 510d 542d 0/3 auto-obsoleted due to no activity on 2025/05/16 13:56
linux-4.19 INFO: task hung in addrconf_dad_work 1 1 2500d 2500d 0/1 auto-closed as invalid on 2019/12/24 18:36
linux-4.19 INFO: task hung in addrconf_dad_work (2) 1 C error 72 1218d 2291d 0/1 upstream: reported C repro on 2020/03/22 17:39
linux-4.14 INFO: task hung in addrconf_dad_work 1 C inconclusive 1 1466d 2072d 0/1 upstream: reported C repro on 2020/10/27 17:48
upstream INFO: task hung in addrconf_dad_work (4) net 1 2632 721d 772d 26/29 fixed on 2024/07/09 19:14
▶ ▼ Fix bisection attempts (4)
Created Duration User Patch Repo Result
2026/06/01 13:34 14m fix candidate upstream error job log
2026/03/24 16:25 1m fix candidate upstream error job log
2026/02/20 09:48 0m fix candidate upstream error job log
2026/01/21 06:43 1m fix candidate upstream error job log

Sample crash report:
INFO: task kworker/u4:4:61 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:4    state:D stack:25032 pid:61    ppid:2      flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6a9/0xcc0 kernel/locking/mutex.c:747
 addrconf_dad_work+0xd4/0x1530 net/ipv6/addrconf.c:4176

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/15 20:54 linux-6.6.y 8cee53b8eaeb c441f497 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: task hung in addrconf_dad_work
2026/04/08 11:22 linux-6.6.y 80de0a958133 2c961e87 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: task hung in addrconf_dad_work
2025/11/26 06:46 linux-6.6.y 1e89a1be4fe9 64219f15 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in addrconf_dad_work
2026/06/11 18:29 linux-6.6.y 924b4a879cbb d93a6ab6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: task hung in addrconf_dad_work
2026/05/07 17:21 linux-6.6.y 258cf62a6dfd cbf9e0fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: task hung in addrconf_dad_work
2026/03/21 04:02 linux-6.6.y 4fc00fe35d46 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in addrconf_dad_work
2026/02/12 08:10 linux-6.6.y 1b4ef5214f17 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: task hung in addrconf_dad_work
2026/02/04 20:45 linux-6.6.y 2cf6f68313dc ea10c935 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: task hung in addrconf_dad_work
* Struck through repros no longer work on HEAD.