INFO: task hung in nfnetlink_rcv_msg

Status: upstream: reported on 2026/08/04 19:29
Reported-by: syzbot+ba3182fdcfe7bfd5ca79@syzkaller.appspotmail.com
First crash: 4d02h, last: 4d02h
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in nfnetlink_rcv_msg (4) netfilter 1 2 441d 502d 0/29 auto-obsoleted due to no activity on 2025/08/22 01:09
upstream INFO: task hung in nfnetlink_rcv_msg (5) prio:normal netfilter 1 C 81 3d06h 218d 0/29 upstream: reported C repro on 2026/01/02 02:25
upstream INFO: task hung in nfnetlink_rcv_msg (3) netfilter 1 syz, C done 5 1337d 1348d 22/29 fixed on 2023/06/08 14:41
upstream INFO: task hung in nfnetlink_rcv_msg netfilter 1 30 2096d 2405d 0/29 auto-closed as invalid on 2021/03/11 10:49
upstream INFO: task hung in nfnetlink_rcv_msg (2) netfilter 1 1 1732d 1732d 0/29 auto-closed as invalid on 2022/02/07 23:39

Sample crash report:
INFO: task syz.1.5563:25549 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.5563      state:D stack:25096 pid:25549 ppid:24589  flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 nfnl_lock net/netfilter/nfnetlink.c:98 [inline]
 nfnetlink_rcv_msg+0xa5c/0x1290 net/netfilter/nfnetlink.c:295

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/04 19:29 linux-6.6.y aa0e49877a2e d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: task hung in nfnetlink_rcv_msg
* Struck through repros no longer work on HEAD.