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Tue, 23 Dec 2025 19:29:13 -0800 (PST) Date: Wed, 24 Dec 2025 11:29:08 +0800 From: Jinchao Wang To: Shakeel Butt Cc: Andrew Morton , Song Liu , Jiri Olsa , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, syzbot+e008db2ac01e282550ee@syzkaller.appspotmail.com Subject: Re: [PATCH] buildid: validate page-backed file before parsing build ID Message-ID: References: <20251223103214.2412446-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Dec 23, 2025 at 11:05:49AM -0800, Shakeel Butt wrote: > Hi Jinchao, > > On Tue, Dec 23, 2025 at 06:32:07PM +0800, Jinchao Wang wrote: > > __build_id_parse() only works on page-backed storage. Its helper paths > > eventually call mapping->a_ops->read_folio(), so explicitly reject VMAs > > that do not map a regular file or lack valid address_space operations. > > > > Reported-by: syzbot+e008db2ac01e282550ee@syzkaller.appspotmail.com > > Signed-off-by: Jinchao Wang > > Check the previous discussion on this at > https://lore.kernel.org/all/20251114193729.251892-1-ssranevjti@gmail.com/ > > The preferred solution was to use kernel_read() call instead of adding > more such checks. Please check and test the patch at > https://lore.kernel.org/20251222205859.3968077-1-shakeel.butt@linux.dev/ > Thanks for the pointer. After reading the discussion and the patch, I agree with you. I also tested your patch, it fixes: https://syzkaller.appspot.com/bug?extid=e008db2ac01e282550ee