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Fri, 20 Feb 2026 06:53:57 -0800 (PST) From: Abd-Alrhman Masalkhi To: Ding Yihan , Thomas =?utf-8?Q?Wei=C3=9Fschuh?= Cc: dwlsalmeida@gmail.com, mchehab@kernel.org, linmag7@gmail.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+96f901260a0b2d29cd1a@syzkaller.appspotmail.com Subject: Re: [PATCH] media: vidtv: fix uninitialized args.buf_sz passed by value In-Reply-To: References: Date: Fri, 20 Feb 2026 15:53:34 +0100 Message-ID: Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi Yihan Ding, On Fri, Feb 20, 2026 at 21:39 +0800, Ding Yihan wrote: > Hi Thomas and Abd-Alrhman, > > While looking into this exact same syzbot report, I noticed that=20 > `vidtv_ts_pcr_write_into()` in the same file also suffers from the > exact same pass-by-value anti-pattern (passing `struct pcr_write_args` b= y value).=20 > > Since `pcr_write_args` also contains implicit padding, it remains a poten= tial trigger > for identical KMSAN uninit-value warnings during fuzzing in the future. > > Also, regarding Thomas's concern about modifying shared data: passing the= struct=20 > as a `const pointer` (e.g., `const struct null_packet_write_args *`)=20 > would perfectly guarantee that the state remains read-only. > > Thomas, would it be worth submitting a separate patch now to fix `vidtv_t= s_pcr_write_into()` > to prevent future KMSAN errors? Or would you prefer this to be addressed = together in Abd-Alrhman's v2? > > Best regards, > Yihan Ding > Thanks for pointing that out. I agree that vidtv_ts_pcr_write_into() should be updated in the same way, since it has identical padding issues. For v2 I=E2=80=99ll incorporate both fixes together and switch both paramet= ers add the const modifier, as you and Thomas suggested. Thanks again for the helpful review. --=20 Best Regards, Abd-Alrhman