Re: [PATCH] dlm: make lockspace join wait killable

[Alexander Aring]

Hi,

On Sat, Sep 19, 2026 at 1:38 PM Nguyen Ngoc Thang
<ngocthang2710.1999@xxxxxxxxx> wrote:
>
> do_uevent() sleeps uninterruptibly until dlm_controld answers the
> ONLINE uevent via sysfs. If the daemon is absent or stuck, a task
> creating a lockspace through /dev/dlm-control blocks forever in D
> state, cannot be killed and trips the hung task detector.
>
> Use wait_event_killable() for the join event and return the error to
> new_lockspace(), which already unwinds through out_recoverd. The
> leave path is left alone as it must not skip teardown.
>
> Reported-by: syzbot+b114bbe890d76037877c@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://syzkaller.appspot.com/bug?extid=b114bbe890d76037877c
> Fixes: e7fd41792fc0 ("[DLM] The core of the DLM for GFS2/CLVM")
> Signed-off-by: Nguyen Ngoc Thang <ngocthang2710.1999@xxxxxxxxx>
> ---
> Problem: syzbot reports "INFO: task hung in do_uevent"
> (https://syzkaller.appspot.com/bug?extid=b114bbe890d76037877c).
>

I can see that syzkaller views this as a problem but syzkaller doesn't
understand how the cluster world works. If dlm_controld dies it is
game over for us, in this case the cluster manager should fence the
node.

- Alex