From: Yash Suthar <yashsuthar983@gmail.com>
To: linux-trace-kernel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, rostedt@goodmis.org,
mhiramat@kernel.org, glider@google.com, nogikh@google.com,
mathieu.desnoyers@efficios.com, syzkaller-bugs@googlegroups.com,
syzbot+2dd9d02f60775ce5c1fb@syzkaller.appspotmail.com
Subject: Re: [syzbot] [trace?] KASAN: use-after-free Write in ring_buffer_read_page
Date: Mon, 8 Jun 2026 19:31:55 +0530 [thread overview]
Message-ID: <20260608140156.136897-1-yashsuthar983@gmail.com> (raw)
In-Reply-To: <CAG_fn=WVfi9=M8VjJQt8jCpXf-0D30-BQDCZZM+FX_0d8V+yhA@mail.gmail.com>
From syzbot initial report, I noticed that
ring_buffer_read_page() checks data_page->order against
buffer->subbuf_order , whereas in while
ring_buffer_subbuf_order_set() updates subbuf_size before
replacing the old pages. I think this allows reader to
use older spare page while observing a newer sub-buffer size.
That could explain the report (KASAN UAF, memset of 16308
bytes order 2 into an order 0 spare), while the AI
reproducer may hit a related race later in via copy_to_user()
tracing_buffers_read().
Before spending more time on a fix, does this sound
correct, or i am missing something in between?
Sincerely,
Yash Suthar
prev parent reply other threads:[~2026-06-08 14:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-02 13:45 [syzbot] [trace?] KASAN: use-after-free Write in ring_buffer_read_page syzbot
2026-06-02 16:28 ` Steven Rostedt
2026-06-03 1:34 ` Masami Hiramatsu
2026-06-03 6:38 ` Aleksandr Nogikh
2026-06-03 8:49 ` Alexander Potapenko
2026-06-08 14:01 ` Yash Suthar [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=20260608140156.136897-1-yashsuthar983@gmail.com \
--to=yashsuthar983@gmail.com \
--cc=glider@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mhiramat@kernel.org \
--cc=nogikh@google.com \
--cc=rostedt@goodmis.org \
--cc=syzbot+2dd9d02f60775ce5c1fb@syzkaller.appspotmail.com \
--cc=syzkaller-bugs@googlegroups.com \
/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