linux-kernel - Re: [syzbot] [netfs?] INFO: task hung in netfs_unbuffered_write

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Message-ID: <CAGudoHHmvU54MU8dsZy422A4+ZzWTVs7LFevP7NpKzwZ1YOqgg@mail.gmail.com>
Date: Sun, 23 Mar 2025 20:52:58 +0100
From: Mateusz Guzik <mjguzik@...il.com>
To: Oleg Nesterov <oleg@...hat.com>
Cc: syzbot <syzbot+62262fdc0e01d99573fc@...kaller.appspotmail.com>, 
	brauner@...nel.org, dhowells@...hat.com, jack@...e.cz, jlayton@...nel.org, 
	kprateek.nayak@....com, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, netfs@...ts.linux.dev, swapnil.sapkal@....com, 
	syzkaller-bugs@...glegroups.com, viro@...iv.linux.org.uk
Subject: Re: [syzbot] [netfs?] INFO: task hung in netfs_unbuffered_write_iter

On Sun, Mar 23, 2025 at 8:47 PM Oleg Nesterov <oleg@...hat.com> wrote:
>
> On 03/23, syzbot wrote:
> >
> > Hello,
> >
> > syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> > INFO: task hung in netfs_unbuffered_write_iter
>
> OK, as expected.
>
> Dear syzbot, thank you.
>
> So far I think this is another problem revealed by aaec5a95d59615523db03dd5
> ("pipe_read: don't wake up the writer if the pipe is still full").
>
> I am going to forget about this report for now and return to it later, when
> all the pending pipe-related changes in vfs.git are merged.
>

How do you ask syzbot for all stacks?

The reproducer *does* use pipes, but it is unclear to me if they play
any role here -- and notably we don't know if there is someone stuck
in pipe code, resulting in not waking up the reported thread.

-- 
Mateusz Guzik <mjguzik gmail.com>