Re: [syzbot] [kernel?] INFO: task hung in ret_from_fork (4)

From: syzbot

Date: Wed Mar 18 2026 - 11:55:39 EST


Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in synchronize_rcu

INFO: task kworker/u8:5:131 blocked for more than 161 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:5 state:D stack:19936 pid:131 tgid:131 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: events_unbound fsnotify_connector_destroy_workfn
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
schedule_timeout+0xc3/0x2c0 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common kernel/sched/completion.c:121 [inline]
wait_for_common kernel/sched/completion.c:132 [inline]
wait_for_completion+0x2cc/0x5e0 kernel/sched/completion.c:153
__synchronize_srcu+0x329/0x3e0 kernel/rcu/srcutree.c:1520


Tested on:

commit: a989fde7 Merge tag 'libnvdimm-fixes-7.0-rc5' of git://..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1724a06a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b643133b3e44c9fd
dashboard link: https://syzkaller.appspot.com/bug?extid=7c11975a7e4a2735d529
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=1140cf4a580000