From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15177EB64D8 for ; Thu, 22 Jun 2023 13:56:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231180AbjFVN4o (ORCPT ); Thu, 22 Jun 2023 09:56:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230395AbjFVN4i (ORCPT ); Thu, 22 Jun 2023 09:56:38 -0400 Received: from mail-wr1-x42c.google.com (mail-wr1-x42c.google.com [IPv6:2a00:1450:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D58DA1BFC for ; Thu, 22 Jun 2023 06:56:36 -0700 (PDT) Received: by mail-wr1-x42c.google.com with SMTP id ffacd0b85a97d-311167ba376so7218424f8f.1 for ; Thu, 22 Jun 2023 06:56:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1687442195; x=1690034195; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=QEW2WXBte3jN1fLJ211gvIuJSeoOteLGjUnX78P98k4=; b=rrCXA0HYW+NRaxuK0LzkBkWHaS32roNXnVTcSlzHkz0PKFiRzi6Lf0a2kxT5sw4sbW jjMVv3gbRGX7y73/rTeAxgcyKJRaEjx8hgeXVmr1KOVjDxufD90egWATGqaHhCdg5lyL CCWBPoNFR/6czRV2XsuleAFb6zUW8evSN0nKHKSOPM/86ngFyJnI//xhzazH6g+ufdey iAvpeJ61KZ0V6PMuriG406hq6r4Jp2DjThmRQnPoG+2mD5V8pIHj1OSfFc1yhmt6x4Iw hJJY0N9IrNvCEy31Uv4j6O7vgmIRqgPp5toYxfIEQfRxNvrKDPf6N2IWfmuS9pLtFoy0 IMUg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687442195; x=1690034195; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=QEW2WXBte3jN1fLJ211gvIuJSeoOteLGjUnX78P98k4=; b=Ub0jIric64AB1Og6C9GIVErC5/ET/wZVVFYjf4JQVvjncj0pZotKEKGmg/vHYrYadP T/CjaEdzMEDZWDlpLEF9pufz+4p/LTXEu3RZEIWBgYQiB3DoiViPe/7vW2BONF+iB5Pa gP7CO9atGxg+i5ahwe8osNbxvPSBdpLQoxFrzQNtDLIurOPQXmlWTurICseqaY+IClBL /r+N3sFM2pRIrxpbKvpKJXo0MZXIjTfaX42cOAtnSiy+3vMFId3jq+xS5ooyQkkqSZHz AaNx2ktYOwI4N81Jtzk/lDRP7q9+sKVZO9C+aq5sxj0BE4gm+3g6++sXy2gu/ANBkr+d Qjmw== X-Gm-Message-State: AC+VfDwn/ywAs4l/3wmbaDh0Dd8Ph3lq1XHBUf5e0WgTLBe6HhiGdeLv C8Xqxc1cuW/+S0caO2ApS6Xbfg== X-Google-Smtp-Source: ACHHUZ6a6EZPyQbiw2QFhMNDMLiHUFcNZTWVMQXmY1brW9zlZbdXXamxNjQ4bnHgoRKMXiHVkCeg6Q== X-Received: by 2002:adf:ec45:0:b0:30f:af06:7320 with SMTP id w5-20020adfec45000000b0030faf067320mr1923670wrn.23.1687442195120; Thu, 22 Jun 2023 06:56:35 -0700 (PDT) Received: from localhost ([102.36.222.112]) by smtp.gmail.com with ESMTPSA id s3-20020a7bc383000000b003f6132f95e6sm18924956wmj.35.2023.06.22.06.56.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Jun 2023 06:56:33 -0700 (PDT) Date: Thu, 22 Jun 2023 16:56:29 +0300 From: Dan Carpenter To: Benjamin Gaignard Cc: mchehab@kernel.org, tfiga@chromium.org, m.szyprowski@samsung.com, ming.qian@nxp.com, ezequiel@vanguardiasur.com.ar, p.zabel@pengutronix.de, gregkh@linuxfoundation.org, hverkuil-cisco@xs4all.nl, nicolas.dufresne@collabora.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev, kernel@collabora.com Subject: Re: [PATCH v3 03/11] media: videobuf2: Remove VB2_MAX_FRAME limit on buffer storage Message-ID: <1d9fea5b-5c74-4fc2-9287-71cd68adbda1@kadam.mountain> References: <20230622131349.144160-1-benjamin.gaignard@collabora.com> <20230622131349.144160-4-benjamin.gaignard@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230622131349.144160-4-benjamin.gaignard@collabora.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 22, 2023 at 03:13:41PM +0200, Benjamin Gaignard wrote: > diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c > index f1ff7af34a9f..86e1e926fa45 100644 > --- a/drivers/media/common/videobuf2/videobuf2-core.c > +++ b/drivers/media/common/videobuf2/videobuf2-core.c > @@ -455,9 +455,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory, > struct vb2_buffer *vb; > int ret; > > - /* Ensure that q->num_buffers+num_buffers is below VB2_MAX_FRAME */ > + /* Ensure that q->num_buffers + num_buffers is UINT_MAX */ > num_buffers = min_t(unsigned int, num_buffers, > - VB2_MAX_FRAME - q->num_buffers); > + UINT_MAX - q->num_buffers); The UINT_MAX limit adds a level of danger. It would be safer to do what the vfs layer does for MAX_RW_COUNT and use "INT_MAX - PAGE_SIZE". That way you can take size + sizeof() and it's only very rarely going to turn negative. Or at least just INT_MAX. I would keep the VB2_MAX_FRAME and define it as: #define VB2_MAX_FRAME (INT_MAX & PAGE_MASK) /* The mask prevents 85% of integer overflows */ > > for (buffer = 0; buffer < num_buffers; ++buffer) { > /* Allocate vb2 buffer structures */ > @@ -858,9 +858,9 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, > /* > * Make sure the requested values and current defaults are sane. > */ > - WARN_ON(q->min_buffers_needed > VB2_MAX_FRAME); > + WARN_ON(q->min_buffers_needed > UINT_MAX); This will trigger a static checker warning because the condition is impossible. regards, dan carpenter