From: Dominique Martinet <asmadeus@codewreck.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: "Song Liu" <song@kernel.org>,
Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
"Christian Brauner" <brauner@kernel.org>,
"Tingmao Wang" <m@maowtm.org>,
v9fs@lists.linux.dev, "Eric Van Hensbergen" <ericvh@kernel.org>,
"Latchesar Ionkov" <lucho@ionkov.net>,
"Christian Schoenebeck" <linux_oss@crudebyte.com>,
"Mickaël Salaün" <mic@digikod.net>, bpf <bpf@vger.kernel.org>
Subject: Re: 9P change breaks bpftrace running in qemu+9p?
Date: Wed, 22 Oct 2025 07:12:02 +0900 [thread overview]
Message-ID: <aPgFMtg2DzzeRreH@codewreck.org> (raw)
In-Reply-To: <CAADnVQKSJTAx-4T4WLFhLPcmJ-Ea5onKG+Z-d9iv48r4A6nJMQ@mail.gmail.com>
Alexei Starovoitov wrote on Tue, Oct 21, 2025 at 09:56:10AM -0700:
> > I am not sure what is the "right" behavior in this case. But this is
> > clearly a change of behavior.
That's definitely wrong, the resulting file was truncated.
Thanks for the repro!
I've sent a fix here:
https://lkml.kernel.org/r/20251022-mmap-regression-v1-1-980365ee524e@codewreck.org
Would be great if you could confirm it fixes your problems, and I'll get
it sent to Linus
> Andrii reported the issue as well:
> https://lore.kernel.org/bpf/CAEf4BzZbCE4tLoDZyUf_aASpgAGFj75QMfSXX4a4dLYixnOiLg@mail.gmail.com/
>
> selftests/bpf was relying on the above behavior too
> which we adjusted already, but
> this looks to be a regression either in 9p or in vfs.
Looks like a 9p bug, sorry :(
--
Dominique Martinet | Asmadeus
prev parent reply other threads:[~2025-10-21 22:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAHzjS_u_SYdt5=2gYO_dxzMKXzGMt-TfdE_ueowg-Hq5tRCAiw@mail.gmail.com>
[not found] ` <e0c7cd4e-4183-40a8-b90d-12e9e29e9890@maowtm.org>
[not found] ` <CAHzjS_sXdnHdFXS8z5XUVU8mCiyVu+WnXVTMxhyegBFRm6Bskg@mail.gmail.com>
[not found] ` <aPaqZpDtc_Thi6Pz@codewreck.org>
[not found] ` <CAHzjS_uEhozUU-g62AkTfSMW58FphVO8udz8qsGzE33jqVpY+g@mail.gmail.com>
[not found] ` <086bb120-22eb-43ff-a486-14e8eeb7dd80@maowtm.org>
[not found] ` <CAHzjS_vrVJrphZqBMxVE4UEfOqgP8XPq6dRuBh9DdWL-SYtO2w@mail.gmail.com>
2025-10-21 16:56 ` 9P change breaks bpftrace running in qemu+9p? Alexei Starovoitov
2025-10-21 22:12 ` Dominique Martinet [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aPgFMtg2DzzeRreH@codewreck.org \
--to=asmadeus@codewreck.org \
--cc=alexei.starovoitov@gmail.com \
--cc=bpf@vger.kernel.org \
--cc=brauner@kernel.org \
--cc=ericvh@kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux_oss@crudebyte.com \
--cc=lucho@ionkov.net \
--cc=m@maowtm.org \
--cc=mic@digikod.net \
--cc=song@kernel.org \
--cc=v9fs@lists.linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).