From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH v2 1/4] drm/rect: Avoid division by zero Date: Tue, 26 Nov 2019 15:40:30 +0100 Message-ID: <20191126144030.GY29965@phenom.ffwll.local> References: <20191122175623.13565-1-ville.syrjala@linux.intel.com> <20191122175623.13565-2-ville.syrjala@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <20191122175623.13565-2-ville.syrjala@linux.intel.com> Sender: stable-owner@vger.kernel.org To: Ville Syrjala Cc: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, stable@vger.kernel.org, Maarten Lankhorst , Benjamin Gaignard , Daniel Vetter List-Id: dri-devel@lists.freedesktop.org On Fri, Nov 22, 2019 at 07:56:20PM +0200, Ville Syrjala wrote: > From: Ville Syrjälä > > Check for zero width/height destination rectangle in > drm_rect_clip_scaled() to avoid a division by zero. > > Cc: stable@vger.kernel.org > Fixes: f96bdf564f3e ("drm/rect: Handle rounding errors in drm_rect_clip_scaled, v3.") > Cc: Maarten Lankhorst > Cc: Benjamin Gaignard > Cc: Daniel Vetter > Testcase: igt/kms_selftest/drm_rect_clip_scaled_div_by_zero > Signed-off-by: Ville Syrjälä Clamping src to 0 if dst is 0 makes sense to me. Reviewed-by: Daniel Vetter > --- > drivers/gpu/drm/drm_rect.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_rect.c b/drivers/gpu/drm/drm_rect.c > index b8363aaa9032..818738e83d06 100644 > --- a/drivers/gpu/drm/drm_rect.c > +++ b/drivers/gpu/drm/drm_rect.c > @@ -54,7 +54,12 @@ EXPORT_SYMBOL(drm_rect_intersect); > > static u32 clip_scaled(u32 src, u32 dst, u32 clip) > { > - u64 tmp = mul_u32_u32(src, dst - clip); > + u64 tmp; > + > + if (dst == 0) > + return 0; > + > + tmp = mul_u32_u32(src, dst - clip); > > /* > * Round toward 1.0 when clipping so that we don't accidentally > -- > 2.23.0 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch 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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5BAF4C432C0 for ; Tue, 26 Nov 2019 14:40:37 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3DA5620656 for ; Tue, 26 Nov 2019 14:40:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3DA5620656 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A7C216E406; Tue, 26 Nov 2019 14:40:36 +0000 (UTC) Received: from mail-wr1-x444.google.com (mail-wr1-x444.google.com [IPv6:2a00:1450:4864:20::444]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7B0FD6E406 for ; Tue, 26 Nov 2019 14:40:34 +0000 (UTC) Received: by mail-wr1-x444.google.com with SMTP id z10so22660449wrs.12 for ; Tue, 26 Nov 2019 06:40:34 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=vDlRkpzIOrPRGh5pysj0vN3V4ARniTOU0E64e7Y7I4k=; b=RHXVWXTS9zqn5gk2sB8XL67oTNCgYyuH9W7RxH/8rpvaDbkv1YCll4KozsuDuvtJi2 QMbxRcwq3X3Jpq5iEPwghih06OmnGnOuHTzRL8aXcvgHoysSgf5xcwJSu7LZ4tJbJWs5 ooQph8um4vZ5Az/5YAAvLM3dDOy8cFJcT22QUhRH+AFxIkKJFHSgD2wzadAX7ybVMtPE 8KOsixrzqz9SQH65LEgmzhlVTrGkxm+BppYGTDZhXD6gh99F4c+0N15iaHd+nYaFFgum UsJU5GkWaH/Vb9K4dK3wXH4gPqgNy1M8sG6pb0s10DfDest6BojcUFcM6gt28/MEvXmN vHQg== X-Gm-Message-State: APjAAAXs7OP6CEdmyZ9qUNZFqoeAUxEfM6yffkXnxUs1SW6T5rfi4QAy QaI1VzcsRqo5khNY32Q7pSCbrw== X-Google-Smtp-Source: APXvYqxUmVBdcCYS7XSP5o8fYGZrhfhKicMhDiOZnyWOiksf2+PAvxuADqC946BHGNEBKb39ApM0Fg== X-Received: by 2002:a05:6000:12c9:: with SMTP id l9mr1904540wrx.304.1574779233142; Tue, 26 Nov 2019 06:40:33 -0800 (PST) Received: from phenom.ffwll.local (212-51-149-96.fiber7.init7.net. [212.51.149.96]) by smtp.gmail.com with ESMTPSA id z26sm1479738wmk.33.2019.11.26.06.40.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Nov 2019 06:40:32 -0800 (PST) Date: Tue, 26 Nov 2019 15:40:30 +0100 From: Daniel Vetter To: Ville Syrjala Subject: Re: [PATCH v2 1/4] drm/rect: Avoid division by zero Message-ID: <20191126144030.GY29965@phenom.ffwll.local> References: <20191122175623.13565-1-ville.syrjala@linux.intel.com> <20191122175623.13565-2-ville.syrjala@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191122175623.13565-2-ville.syrjala@linux.intel.com> X-Operating-System: Linux phenom 5.3.0-2-amd64 User-Agent: Mutt/1.12.2 (2019-09-21) X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=vDlRkpzIOrPRGh5pysj0vN3V4ARniTOU0E64e7Y7I4k=; b=We11rIf9pkSTfvXQfufaU9H4/tUZLZP0zPiq0QyBZx7rXYqB/Lbo00B9w3TyI38XDv IhhGUDrIyAjy3QwAIPo/ExlDP8YSHI0593gfyeq7rRfh69HiUpK3fujAH1PdUg1sySIg sCASiOk+mxUmzGq9FfOGPhaUbRwd8+9WobLFc= X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Benjamin Gaignard , intel-gfx@lists.freedesktop.org, stable@vger.kernel.org, dri-devel@lists.freedesktop.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Message-ID: <20191126144030.N-jAewSomknRRuCzIJ8iDiVINg2zKY4ad1XKpvpYM6c@z> T24gRnJpLCBOb3YgMjIsIDIwMTkgYXQgMDc6NTY6MjBQTSArMDIwMCwgVmlsbGUgU3lyamFsYSB3 cm90ZToKPiBGcm9tOiBWaWxsZSBTeXJqw6Rsw6QgPHZpbGxlLnN5cmphbGFAbGludXguaW50ZWwu Y29tPgo+IAo+IENoZWNrIGZvciB6ZXJvIHdpZHRoL2hlaWdodCBkZXN0aW5hdGlvbiByZWN0YW5n bGUgaW4KPiBkcm1fcmVjdF9jbGlwX3NjYWxlZCgpIHRvIGF2b2lkIGEgZGl2aXNpb24gYnkgemVy by4KPiAKPiBDYzogc3RhYmxlQHZnZXIua2VybmVsLm9yZwo+IEZpeGVzOiBmOTZiZGY1NjRmM2Ug KCJkcm0vcmVjdDogSGFuZGxlIHJvdW5kaW5nIGVycm9ycyBpbiBkcm1fcmVjdF9jbGlwX3NjYWxl ZCwgdjMuIikKPiBDYzogTWFhcnRlbiBMYW5raG9yc3QgPG1hYXJ0ZW4ubGFua2hvcnN0QGxpbnV4 LmludGVsLmNvbT4KPiBDYzogQmVuamFtaW4gR2FpZ25hcmQgPGJlbmphbWluLmdhaWduYXJkQHN0 LmNvbT4KPiBDYzogRGFuaWVsIFZldHRlciA8ZGFuaWVsQGZmd2xsLmNoPgo+IFRlc3RjYXNlOiBp Z3Qva21zX3NlbGZ0ZXN0L2RybV9yZWN0X2NsaXBfc2NhbGVkX2Rpdl9ieV96ZXJvCj4gU2lnbmVk LW9mZi1ieTogVmlsbGUgU3lyasOkbMOkIDx2aWxsZS5zeXJqYWxhQGxpbnV4LmludGVsLmNvbT4K CkNsYW1waW5nIHNyYyB0byAwIGlmIGRzdCBpcyAwIG1ha2VzIHNlbnNlIHRvIG1lLgoKUmV2aWV3 ZWQtYnk6IERhbmllbCBWZXR0ZXIgPGRhbmllbC52ZXR0ZXJAZmZ3bGwuY2g+Cgo+IC0tLQo+ICBk cml2ZXJzL2dwdS9kcm0vZHJtX3JlY3QuYyB8IDcgKysrKysrLQo+ICAxIGZpbGUgY2hhbmdlZCwg NiBpbnNlcnRpb25zKCspLCAxIGRlbGV0aW9uKC0pCj4gCj4gZGlmZiAtLWdpdCBhL2RyaXZlcnMv Z3B1L2RybS9kcm1fcmVjdC5jIGIvZHJpdmVycy9ncHUvZHJtL2RybV9yZWN0LmMKPiBpbmRleCBi ODM2M2FhYTkwMzIuLjgxODczOGU4M2QwNiAxMDA2NDQKPiAtLS0gYS9kcml2ZXJzL2dwdS9kcm0v ZHJtX3JlY3QuYwo+ICsrKyBiL2RyaXZlcnMvZ3B1L2RybS9kcm1fcmVjdC5jCj4gQEAgLTU0LDcg KzU0LDEyIEBAIEVYUE9SVF9TWU1CT0woZHJtX3JlY3RfaW50ZXJzZWN0KTsKPiAgCj4gIHN0YXRp YyB1MzIgY2xpcF9zY2FsZWQodTMyIHNyYywgdTMyIGRzdCwgdTMyIGNsaXApCj4gIHsKPiAtCXU2 NCB0bXAgPSBtdWxfdTMyX3UzMihzcmMsIGRzdCAtIGNsaXApOwo+ICsJdTY0IHRtcDsKPiArCj4g KwlpZiAoZHN0ID09IDApCj4gKwkJcmV0dXJuIDA7Cj4gKwo+ICsJdG1wID0gbXVsX3UzMl91MzIo c3JjLCBkc3QgLSBjbGlwKTsKPiAgCj4gIAkvKgo+ICAJICogUm91bmQgdG93YXJkIDEuMCB3aGVu IGNsaXBwaW5nIHNvIHRoYXQgd2UgZG9uJ3QgYWNjaWRlbnRhbGx5Cj4gLS0gCj4gMi4yMy4wCj4g CgotLSAKRGFuaWVsIFZldHRlcgpTb2Z0d2FyZSBFbmdpbmVlciwgSW50ZWwgQ29ycG9yYXRpb24K aHR0cDovL2Jsb2cuZmZ3bGwuY2gKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX18KZHJpLWRldmVsIG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRl c2t0b3Aub3JnCmh0dHBzOi8vbGlzdHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8v ZHJpLWRldmVs