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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 45F57C433EA for ; Thu, 23 Jul 2020 22:32:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E3D820792 for ; Thu, 23 Jul 2020 22:32:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="lvaXW0EH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727837AbgGWWcT (ORCPT ); Thu, 23 Jul 2020 18:32:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726608AbgGWWcT (ORCPT ); Thu, 23 Jul 2020 18:32:19 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1626AC0619D3 for ; Thu, 23 Jul 2020 15:32:19 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id l6so3333582plt.7 for ; Thu, 23 Jul 2020 15:32:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=rcHiH1Tqs5ADJ+MGb3vcjbWBOdmK6BVfKbafmPqedI4=; b=lvaXW0EH58h+/+Oelkh/2EltLVN21JeGtH9oA9rq4r7QwYFgUzxZHdbdpcj6L0OT4+ NUzurvHLRVuiuFxDjQ4s+3XcN+azqQ4Z9/kmtqIXftHCj7BYQ13jO1kHZnF5qpLkb/5/ Db2jc9KY+6XmdRAlWCgKbg6WL/mHQCeBQS4JM= 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:in-reply-to; bh=rcHiH1Tqs5ADJ+MGb3vcjbWBOdmK6BVfKbafmPqedI4=; b=BJd39YCXfQTXzjP0JC3IVw0yvBG7+UBHq5ueMXqtG3R2kP643/SbMJGMKgtTmIairb c4h+l94fSUzE+5fNtiXk+m0zusdvJRabeEjBxSdEMWZhQVZH9EYAhouWLwBh51BRY5pE CNzsdy9bYRPFHNyreWyj+wvXXEv6fP9KiBm3WbLgEeCPDj4lUEiOGJu43woxAaHztcnR xG3DE53rjwOtJCjLgRnU+OZmUAmVHkgo5RVdmNv3zurw1Fi5fCV8mPDtwU/KBTllABGH OhLaoyXcM0D4DrgL8PxkwvxAW4xPdtNaBjDLh1AzGj6iCkDFGbB1fAEQwq75i2YnGsjy i/rg== X-Gm-Message-State: AOAM532qBbl14h3QOSLseqT700OnjGYkRchqEVboRgTuSfAWEf1ICt5n kLOK4/3GqQzngG+FcokRbbfoNQ== X-Google-Smtp-Source: ABdhPJx/HbAN/k8ICmlNADe+1VuDo0tfRRzSOZ3OPXagZgfd/TkGMW8mipyokLFnWdO7JgsaGPhN/w== X-Received: by 2002:a17:90a:1b64:: with SMTP id q91mr2452247pjq.119.1595543538591; Thu, 23 Jul 2020 15:32:18 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id m68sm3815562pje.24.2020.07.23.15.32.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Jul 2020 15:32:17 -0700 (PDT) Date: Thu, 23 Jul 2020 15:32:16 -0700 From: Kees Cook To: Mazin Rezk Cc: "linux-kernel@vger.kernel.org" , "amd-gfx@lists.freedesktop.org" , "dri-devel@lists.freedesktop.org" , "akpm@linux-foundation.org" , "christian.koenig@amd.com" , "harry.wentland@amd.com" , "nicholas.kazlauskas@amd.com" , "sunpeng.li@amd.com" , "alexander.deucher@amd.com" , "1i5t5.duncan@cox.net" <1i5t5.duncan@cox.net>, "mphantomx@yahoo.com.br" , "regressions@leemhuis.info" , "anthony.ruhier@gmail.com" , "pmenzel@molgen.mpg.de" Subject: Re: [PATCH] amdgpu_dm: fix nonblocking atomic commit use-after-free Message-ID: <202007231524.A24720C@keescook> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 23, 2020 at 09:10:15PM +0000, Mazin Rezk wrote: > When amdgpu_dm_atomic_commit_tail is running in the workqueue, > drm_atomic_state_put will get called while amdgpu_dm_atomic_commit_tail is > running, causing a race condition where state (and then dm_state) is > sometimes freed while amdgpu_dm_atomic_commit_tail is running. This bug has > occurred since 5.7-rc1 and is well documented among polaris11 users [1]. > > Prior to 5.7, this was not a noticeable issue since the freelist pointer > was stored at the beginning of dm_state (base), which was unused. After > changing the freelist pointer to be stored in the middle of the struct, the > freelist pointer overwrote the context, causing dc_state to become garbage > data and made the call to dm_enable_per_frame_crtc_master_sync dereference > a freelist pointer. > > This patch fixes the aforementioned issue by calling drm_atomic_state_get > in amdgpu_dm_atomic_commit before drm_atomic_helper_commit is called and > drm_atomic_state_put after amdgpu_dm_atomic_commit_tail is complete. > > According to my testing on 5.8.0-rc6, this should fix bug 207383 on > Bugzilla [1]. > > [1] https://bugzilla.kernel.org/show_bug.cgi?id=207383 Nice work tracking this down! > Fixes: 3202fa62f ("slub: relocate freelist pointer to middle of object") I do, however, object to this Fixes tag. :) The flaw appears to have been with amdgpu_dm's reference tracking of "state" in the nonblocking case. (How this reference counting is supposed to work correctly, though, I'm not sure.) If I look at where the drm helper was split from being the default callback, it looks like this was what introduced the bug: da5c47f682ab ("drm/amd/display: Remove acrtc->stream") ? 3202fa62f certainly exposed it much more quickly, but there was a race even without 3202fa62f where something could have realloced the memory and written over it. -- Kees Cook 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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 64D52C433E3 for ; Fri, 24 Jul 2020 00:11:08 +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 38C8D206E3 for ; Fri, 24 Jul 2020 00:11:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="lvaXW0EH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 38C8D206E3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=amd-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 242376E8A5; Fri, 24 Jul 2020 00:11:07 +0000 (UTC) Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0672B6E486 for ; Thu, 23 Jul 2020 22:32:19 +0000 (UTC) Received: by mail-pl1-x644.google.com with SMTP id w17so3324258ply.11 for ; Thu, 23 Jul 2020 15:32:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=rcHiH1Tqs5ADJ+MGb3vcjbWBOdmK6BVfKbafmPqedI4=; b=lvaXW0EH58h+/+Oelkh/2EltLVN21JeGtH9oA9rq4r7QwYFgUzxZHdbdpcj6L0OT4+ NUzurvHLRVuiuFxDjQ4s+3XcN+azqQ4Z9/kmtqIXftHCj7BYQ13jO1kHZnF5qpLkb/5/ Db2jc9KY+6XmdRAlWCgKbg6WL/mHQCeBQS4JM= 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:in-reply-to; bh=rcHiH1Tqs5ADJ+MGb3vcjbWBOdmK6BVfKbafmPqedI4=; b=Xt0Qt9hzXWad+acRkbZleVnKOPMnHJpe1qXfBJGJTM4rUTuVH1+Tgn5++xSRS1ODQ3 wqhkRv+lRPgBi8CVA2TKQGr5OypYAJx39gQ8GVKnzE6cxQk09AaEUoF1glMvvlQcssfB YoFo3s+llwHqvLT/IeauINbgrI3HCbxLqgFvAt0jVcARHjy4cn0FTWXgLgYGlsKtsem9 LokygKRrxHNOfYfwy7fO6HkhKokS88ZTdBQi+GhIWk4R2oqNquRbLPari3ee6MkSBMuH f+j1PkWPXy+1XVty+0VjddSMDbBNGQhEiwP7zxmo5hj6skE8in/FvP1xlxcE7HZ0kajW JHGw== X-Gm-Message-State: AOAM531ClYuorEgKdje8OGX0NY4Cj0qKL1SE4AjgQnj58ZPWryrwIleG lc/qo7VA2B4xXp/Zry/aPMc7Xw== X-Google-Smtp-Source: ABdhPJx/HbAN/k8ICmlNADe+1VuDo0tfRRzSOZ3OPXagZgfd/TkGMW8mipyokLFnWdO7JgsaGPhN/w== X-Received: by 2002:a17:90a:1b64:: with SMTP id q91mr2452247pjq.119.1595543538591; Thu, 23 Jul 2020 15:32:18 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id m68sm3815562pje.24.2020.07.23.15.32.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Jul 2020 15:32:17 -0700 (PDT) Date: Thu, 23 Jul 2020 15:32:16 -0700 From: Kees Cook To: Mazin Rezk Subject: Re: [PATCH] amdgpu_dm: fix nonblocking atomic commit use-after-free Message-ID: <202007231524.A24720C@keescook> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Mailman-Approved-At: Fri, 24 Jul 2020 00:11:04 +0000 X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "pmenzel@molgen.mpg.de" , "anthony.ruhier@gmail.com" , "1i5t5.duncan@cox.net" <1i5t5.duncan@cox.net>, "sunpeng.li@amd.com" , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "nicholas.kazlauskas@amd.com" , "regressions@leemhuis.info" , "amd-gfx@lists.freedesktop.org" , "alexander.deucher@amd.com" , "akpm@linux-foundation.org" , "mphantomx@yahoo.com.br" , "harry.wentland@amd.com" , "christian.koenig@amd.com" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On Thu, Jul 23, 2020 at 09:10:15PM +0000, Mazin Rezk wrote: > When amdgpu_dm_atomic_commit_tail is running in the workqueue, > drm_atomic_state_put will get called while amdgpu_dm_atomic_commit_tail is > running, causing a race condition where state (and then dm_state) is > sometimes freed while amdgpu_dm_atomic_commit_tail is running. This bug has > occurred since 5.7-rc1 and is well documented among polaris11 users [1]. > > Prior to 5.7, this was not a noticeable issue since the freelist pointer > was stored at the beginning of dm_state (base), which was unused. After > changing the freelist pointer to be stored in the middle of the struct, the > freelist pointer overwrote the context, causing dc_state to become garbage > data and made the call to dm_enable_per_frame_crtc_master_sync dereference > a freelist pointer. > > This patch fixes the aforementioned issue by calling drm_atomic_state_get > in amdgpu_dm_atomic_commit before drm_atomic_helper_commit is called and > drm_atomic_state_put after amdgpu_dm_atomic_commit_tail is complete. > > According to my testing on 5.8.0-rc6, this should fix bug 207383 on > Bugzilla [1]. > > [1] https://bugzilla.kernel.org/show_bug.cgi?id=207383 Nice work tracking this down! > Fixes: 3202fa62f ("slub: relocate freelist pointer to middle of object") I do, however, object to this Fixes tag. :) The flaw appears to have been with amdgpu_dm's reference tracking of "state" in the nonblocking case. (How this reference counting is supposed to work correctly, though, I'm not sure.) If I look at where the drm helper was split from being the default callback, it looks like this was what introduced the bug: da5c47f682ab ("drm/amd/display: Remove acrtc->stream") ? 3202fa62f certainly exposed it much more quickly, but there was a race even without 3202fa62f where something could have realloced the memory and written over it. -- Kees Cook _______________________________________________ amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx 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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 37EF5C433E4 for ; Thu, 23 Jul 2020 22:32:21 +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 08F1520737 for ; Thu, 23 Jul 2020 22:32:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="lvaXW0EH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 08F1520737 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org 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 563B86E517; Thu, 23 Jul 2020 22:32:20 +0000 (UTC) Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by gabe.freedesktop.org (Postfix) with ESMTPS id 06A7A6E512 for ; Thu, 23 Jul 2020 22:32:18 +0000 (UTC) Received: by mail-pl1-x644.google.com with SMTP id q17so3329727pls.9 for ; Thu, 23 Jul 2020 15:32:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=rcHiH1Tqs5ADJ+MGb3vcjbWBOdmK6BVfKbafmPqedI4=; b=lvaXW0EH58h+/+Oelkh/2EltLVN21JeGtH9oA9rq4r7QwYFgUzxZHdbdpcj6L0OT4+ NUzurvHLRVuiuFxDjQ4s+3XcN+azqQ4Z9/kmtqIXftHCj7BYQ13jO1kHZnF5qpLkb/5/ Db2jc9KY+6XmdRAlWCgKbg6WL/mHQCeBQS4JM= 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:in-reply-to; bh=rcHiH1Tqs5ADJ+MGb3vcjbWBOdmK6BVfKbafmPqedI4=; b=h+95IdziCZz6KCjmLFlSpyw+9n7kui2ldjztNre19R4T9pqAAar82yh/Bm3q40H7MM bSu62e6VdeRGifydTkCl8TX64bbETZqz5lkQ0xXHcUYEoFy94nJ3U5tcPOePqmVutGFG +/0JNq9zeVOobWlMYQbCIPleahSCbvHNLIIk4YeT2uMUA/1b8pPQewXqNYHDtehZ5qdX QrkDNmOLCzgKRD0lNIdyiOSeL9D4T8D4u2azryAbEHr09ncfwZoZa+Ra4TXNQ5oclBfz Pcs3ERZw7mdCONS73raRER6Zt+5fuMJznlxosP7gJqyrcITwIs57uxD8FOJvavJUHLJf DPAw== X-Gm-Message-State: AOAM532KsTSPDT/SE7uda68mWzXk6iHDrR2uYj+IHyku/1BP7LyoZGgq 1/GPHQaUNiQPUchJau6YKAkCMg== X-Google-Smtp-Source: ABdhPJx/HbAN/k8ICmlNADe+1VuDo0tfRRzSOZ3OPXagZgfd/TkGMW8mipyokLFnWdO7JgsaGPhN/w== X-Received: by 2002:a17:90a:1b64:: with SMTP id q91mr2452247pjq.119.1595543538591; Thu, 23 Jul 2020 15:32:18 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id m68sm3815562pje.24.2020.07.23.15.32.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Jul 2020 15:32:17 -0700 (PDT) Date: Thu, 23 Jul 2020 15:32:16 -0700 From: Kees Cook To: Mazin Rezk Subject: Re: [PATCH] amdgpu_dm: fix nonblocking atomic commit use-after-free Message-ID: <202007231524.A24720C@keescook> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "pmenzel@molgen.mpg.de" , "anthony.ruhier@gmail.com" , "1i5t5.duncan@cox.net" <1i5t5.duncan@cox.net>, "sunpeng.li@amd.com" , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "nicholas.kazlauskas@amd.com" , "regressions@leemhuis.info" , "amd-gfx@lists.freedesktop.org" , "alexander.deucher@amd.com" , "akpm@linux-foundation.org" , "mphantomx@yahoo.com.br" , "christian.koenig@amd.com" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Thu, Jul 23, 2020 at 09:10:15PM +0000, Mazin Rezk wrote: > When amdgpu_dm_atomic_commit_tail is running in the workqueue, > drm_atomic_state_put will get called while amdgpu_dm_atomic_commit_tail is > running, causing a race condition where state (and then dm_state) is > sometimes freed while amdgpu_dm_atomic_commit_tail is running. This bug has > occurred since 5.7-rc1 and is well documented among polaris11 users [1]. > > Prior to 5.7, this was not a noticeable issue since the freelist pointer > was stored at the beginning of dm_state (base), which was unused. After > changing the freelist pointer to be stored in the middle of the struct, the > freelist pointer overwrote the context, causing dc_state to become garbage > data and made the call to dm_enable_per_frame_crtc_master_sync dereference > a freelist pointer. > > This patch fixes the aforementioned issue by calling drm_atomic_state_get > in amdgpu_dm_atomic_commit before drm_atomic_helper_commit is called and > drm_atomic_state_put after amdgpu_dm_atomic_commit_tail is complete. > > According to my testing on 5.8.0-rc6, this should fix bug 207383 on > Bugzilla [1]. > > [1] https://bugzilla.kernel.org/show_bug.cgi?id=207383 Nice work tracking this down! > Fixes: 3202fa62f ("slub: relocate freelist pointer to middle of object") I do, however, object to this Fixes tag. :) The flaw appears to have been with amdgpu_dm's reference tracking of "state" in the nonblocking case. (How this reference counting is supposed to work correctly, though, I'm not sure.) If I look at where the drm helper was split from being the default callback, it looks like this was what introduced the bug: da5c47f682ab ("drm/amd/display: Remove acrtc->stream") ? 3202fa62f certainly exposed it much more quickly, but there was a race even without 3202fa62f where something could have realloced the memory and written over it. -- Kees Cook _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel