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: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-20 17:40 9P change breaks bpftrace running in qemu+9p? Song Liu
2025-10-20 18:40 ` Tingmao Wang
2025-10-20 19:40 ` Song Liu
2025-10-20 21:32 ` Dominique Martinet
2025-10-20 21:52 ` Song Liu
2025-10-21 0:54 ` Tingmao Wang
2025-10-21 6:49 ` Song Liu
2025-10-21 16:56 ` Alexei Starovoitov
2025-10-21 22:12 ` Dominique Martinet [this message]
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