From nobody Fri Dec 19 17:18:14 2025 Received: from out162-62-57-137.mail.qq.com (out162-62-57-137.mail.qq.com [162.62.57.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A15E72627; Tue, 14 Oct 2025 00:35:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=162.62.57.137 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760402147; cv=none; b=kB/bk1TKcZHsGj0FKI14eXJiQ2BQkJXJWtpzpQlrEsVBaS3PIIDf9C17b2dxti3lVt7ThsfHYmu/ps1k8YnuzDWxVcSGhQbX1dqM+T8gTjDgQ/ZACr4gUJMmjGeltz0JkOHy+SehMHGAsBmyqPgKsftOUW4jFkP4txwqprlBZSU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760402147; c=relaxed/simple; bh=WbqyGpKb/zLKbH7fHA4aAvojTSwpNDo8iN+Qgagm4oI=; h=Message-ID:From:To:Cc:Subject:Date:In-Reply-To:References: MIME-Version; b=RIsik9+rfFHs9T9PjA/1/gS47R4FOeiXnvGo0TED+KlnP5R7mCyBrOgl+X3iGTbPqDD3dTbxt4OM3ggqkt+2F7nL6mgRk1GOqYHS93VdHgZwSBn8hBYA5vKSo8UsoSW3giN+y7cPl7VJN1wrGXg56LKQQByX85i0QLpI4fBUc0A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com; spf=pass smtp.mailfrom=qq.com; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b=YR2fKaES; arc=none smtp.client-ip=162.62.57.137 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=qq.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b="YR2fKaES" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qq.com; s=s201512; t=1760401833; bh=HvGgaFWBTdNE6Bay2kvJlLwmy4Dyj/uwmy1sSo7Y4D4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YR2fKaESW35SsSADdb3oYr5p72d3MkYzULJ1sRqz1G50/K6FRwVXTUAuwAfxjBAxV do4wyh3JcnVfXvIgXGmZwh4bvagsaxuHak2DjQnHTrlPxKae+IZFBlOld9PjyZiW0S 7unhCrQ6ELtdIMHFnjFBxkhK2gE5Pit02InI+qgo= Received: from pek-lxu-l1.corp.ad.wrs.com ([111.198.230.220]) by newxmesmtplogicsvrsza29-0.qq.com (NewEsmtp) with SMTP id 79F01285; Tue, 14 Oct 2025 08:30:31 +0800 X-QQ-mid: xmsmtpt1760401831tv6k674kl Message-ID: X-QQ-XMAILINFO: NmRjDopJZVxOIDYKzhLIqywTpTLqV8h8kOzVqIJHfaEQbkB/pTKdGXcNqA8b/V OHr0n+qT+aEdUDyIsrxlCBDmn8DrRv/aYdF9cvl0h8B//moQeVy9qz9n4rZsZlZmXSuvjAzVSC9k KRbO0/iye3A993GEh/Vx9J9BREjzVDixQCW2vO+PaRYR+C9PBRZtjuzhoksLkdCcpKvNMJarwCEs o7SqNQr6X78FMiwlC9N0FFcy5TRi7sJ4D2dPeQLFyaZfGZoy1HohMEJNswYyXzIzCN5CVmMkwkuR q3DGcZiRdnz3iqSGPFCnGm4Yxolbltov4eYjhAINRXpi7Dp1Vme/HcrJL0ssVXldjjWKuRq65o3E IjX9jNpuXtl24MdE2NMDCLRPIFyNj/B+X4AT3x6ued6+f127DoDILhqz/1Pjq6C2PjezQZHuNqeX aE4Oo/oXzUjmKmzVHBUOUatwDyzOtI5MODe8EhMj5SPbHsDuKMNCj6NIMbb9i8dCzUO1uVGIP355 sam367rsr8GwmtUnMJQimPL8lymRlMdao/xRjb7tX4NfFO3EJ00ezPLhH7J8lHtSX6BJdizz8U5k jlDnnfdBiKEsrmkpm3xDdRAXWQ1UbbYimeWH0c5Z9xuba492ea2PJ3ZH5LiXTHEAeHnpJerlcbnB 9XwgurDCMkxDBiC4Ier+Nv6aaj7g8sVxmQd1cn7cyNe/He7Wf8/1tTOAFE6GjebMq/l7nnJy9ZdQ hbXD0oKgezGlAM1hQ3oLaJTrlbWAY/Bc5JOC22BqD2DWq96JVLaMSaHOeMb+cz/yTwzAgzGrnBK1 q7FX5Pl2WaEv6rBKK70Lj+HTahfNRxFlpk99v/mA2qrq9YtE0RsBIoREkI7l5nzkeebtvwMZIk58 m977fYaYzegO2OgdsLbgVUHxAVQ3v/pXdcjtyhcFtPz+Ykm/lHEVOq1KVyeOs9RId8ly0Zh71w/B MQEQhrW+2bY10bU0inYcfHKVspayh+zZYKeRBw1egQlYGixflafH4hkhe0yDRIDRE2LQ967SNAiP efKKCrNqd4ZgWd4u0O X-QQ-XMRINFO: Mp0Kj//9VHAxr69bL5MkOOs= From: Edward Adam Davis To: eadavis@qq.com Cc: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, mchehab@kernel.org, syzbot+480edd2cadb85ddb4bbe@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com Subject: [PATCH V2] media: dvb-usb: Optimizing err() output Date: Tue, 14 Oct 2025 08:30:31 +0800 X-OQ-MSGID: <20251014003031.3996942-2-eadavis@qq.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" syzbot reported a uninit-value in pctv452e_i2c_msg. [1] When the snd_len or rcv_len check fails and jumps to failed, buf is uninitialized, triggering the uninit-value issue. Setting the err() output buf byte count to 0 before jumping to failed before initializing buf and setting it to 7 after initializing buf avoids this warning. [1] BUG: KMSAN: uninit-value in hex_string+0x681/0x740 lib/vsprintf.c:1220 pctv452e_i2c_msg+0x82a/0x8f0 drivers/media/usb/dvb-usb/pctv452e.c:467 pctv452e_i2c_xfer+0x2e6/0x4c0 drivers/media/usb/dvb-usb/pctv452e.c:502 Reported-by: syzbot+480edd2cadb85ddb4bbe@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3D480edd2cadb85ddb4bbe Signed-off-by: Edward Adam Davis --- V1 -> V2: subject typos drivers/media/usb/dvb-usb/pctv452e.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/media/usb/dvb-usb/pctv452e.c b/drivers/media/usb/dvb-u= sb/pctv452e.c index 5094de9a312e..3b6e86a8e9ff 100644 --- a/drivers/media/usb/dvb-usb/pctv452e.c +++ b/drivers/media/usb/dvb-usb/pctv452e.c @@ -420,7 +420,7 @@ static int pctv452e_i2c_msg(struct dvb_usb_device *d, u= 8 addr, struct pctv452e_state *state =3D d->priv; u8 *buf; u8 id; - int ret; + int ret, plen =3D 0; =20 buf =3D kmalloc(64, GFP_KERNEL); if (!buf) @@ -432,6 +432,7 @@ static int pctv452e_i2c_msg(struct dvb_usb_device *d, u= 8 addr, if (snd_len > 64 - 7 || rcv_len > 64 - 7) goto failed; =20 + plen =3D 7; buf[0] =3D SYNC_BYTE_OUT; buf[1] =3D id; buf[2] =3D PCTV_CMD_I2C; @@ -466,7 +467,7 @@ static int pctv452e_i2c_msg(struct dvb_usb_device *d, u= 8 addr, failed: err("I2C error %d; %02X %02X %02X %02X %02X -> %*ph", ret, SYNC_BYTE_OUT, id, addr << 1, snd_len, rcv_len, - 7, buf); + plen, buf); =20 kfree(buf); return ret; --=20 2.43.0