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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 3EA11C43334 for ; Fri, 24 Jun 2022 11:52:20 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6D5A610EF87; Fri, 24 Jun 2022 11:52:19 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id D1DE010EF87; Fri, 24 Jun 2022 11:52:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656071537; x=1687607537; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=QF6lLBFa+kKvV06bPClHFUil6kWzGMWJMZlPHIkiygM=; b=le3H+2Z5AzAzsK+WReboXk6/IK5ncR0GsRNvYhzls53TKuRt451JiwNW oLHblQ7mZt/FjEPSa5ICbTimXvvc9Ew6ybV1f/fGWZK7+xi4s1WhsIpY9 PnxWr/yIXPOCjINQCegqnSWnUXd5d4SDkpywpNoKBSsujpl0yXJjVMMyw 6OhNbXsFhUWDE6JRVaVG8ywhU7UnbECC8hHswNNelxEfPV59DakodyUUU mHotPHYoEhgWdbjCmvS8eStEF5E4/W7zv5oo2Jubp+X2rI5m3+W+kLdWo /6Wf//47e/PSn6BL2criA7qbzLAbf4laiph5WFNutEEbNSkQp99NrBtLG w==; X-IronPort-AV: E=McAfee;i="6400,9594,10387"; a="281027964" X-IronPort-AV: E=Sophos;i="5.92,218,1650956400"; d="scan'208";a="281027964" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2022 04:52:17 -0700 X-IronPort-AV: E=Sophos;i="5.92,218,1650956400"; d="scan'208";a="645241759" Received: from singuva-mobl.amr.corp.intel.com (HELO intel.com) ([10.252.35.188]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2022 04:52:16 -0700 Date: Fri, 24 Jun 2022 13:52:13 +0200 From: Andi Shyti To: Andrzej Hajda Message-ID: References: <20220624113528.2159210-1-andrzej.hajda@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220624113528.2159210-1-andrzej.hajda@intel.com> Subject: Re: [Intel-gfx] [PATCH] drm/i915/selftests: fix subtraction overflow bug X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx-trybot@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, Chris Wilson Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Hi Andrzej, On Fri, Jun 24, 2022 at 01:35:28PM +0200, Andrzej Hajda wrote: > On some machines hole_end can be small enough to cause subtraction > overflow. On the other side (addr + 2 * min_alignment) can overflow > in case of mock tests. This patch should handle both cases. > > Fixes: e1c5f754067b59 ("drm/i915: Avoid overflow in computing pot_hole loop termination") > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3674 > Signed-off-by: Andrzej Hajda > --- > drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c > index 8633bec18fa75e..ab9f17fc85bcf2 100644 > --- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c > +++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c > @@ -742,7 +742,7 @@ static int pot_hole(struct i915_address_space *vm, > u64 addr; > > for (addr = round_up(hole_start + min_alignment, step) - min_alignment; > - addr <= round_down(hole_end - (2 * min_alignment), step) - min_alignment; > + hole_end > addr && hole_end - addr >= 2 * min_alignment; Reviewed-by: Andi Shyti Thanks, Andi