Attachment 108983 Details for Bug 78770 – Proposed fix

[patch] Proposed fix

0001-i965-Fix-segfault-in-WebGL-Conformance-on-Ivybridge.patch (text/plain), 2.09 KB, created by Chad Versace on 2014-11-05 19:00:49 UTC

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Creator: Chad Versace

Created: 2014-11-05 19:00:49 UTC

Size: 2.09 KB

patch

obsolete

>From e08dbb21a4698950471bbb3aebfeda85b3a32989 Mon Sep 17 00:00:00 2001
>From: Chad Versace <chad@kiwitree.net>
>Date: Wed, 5 Nov 2014 10:14:11 -0800
>Subject: [PATCH] i965: Fix segfault in WebGL Conformance on Ivybridge
>
>Fixes regression of WebGL Conformance test texture-size-limit [1] on
>Ivybridge Mobile GT2 0x0166 with Google Chrome R38.
>
>Regression introduced by
>
>    commit 6c044231535b93c5d16404528946cad618d96bd9
>    Author: Kenneth Graunke <kenneth@whitecape.org>
>    Date:   Sun Feb 2 02:58:42 2014 -0800
>
>        i965: Bump GL_MAX_CUBE_MAP_TEXTURE_SIZE to 8192.
>
>The test regressed because the pointer offset arithmetic in
>intel_miptree_map_gtt() overflows for large textures. The pointer
>arithmetic uses 32-bit ints :(.
>
>[1] https://github.com/KhronosGroup/WebGL/blob/52f0dc240f04dce31b1b8e2b8107fe2b8332dc90/sdk/tests/conformance/textures/texture-size-limit.html
>
>Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=78770
>Fixes: Intel CHRMOS-1377
>Reported-by: Lu Hua <huax.lu@intel.com>
>Signed-off-by: Chad Versace <chad@kiwitree.net>
>---
> src/mesa/drivers/dri/i965/intel_mipmap_tree.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
>diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
>index 8fda25d..24e217c 100644
>--- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
>+++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
>@@ -1769,7 +1769,16 @@ intel_miptree_map_gtt(struct brw_context *brw,
>       y += image_y;
> 
>       map->stride = mt->pitch;
>-      map->ptr = base + y * map->stride + x * mt->cpp;
>+
>+      /* The variables in below pointer arithmetic are 32-bit. The arithmetic
>+       * overflows for large textures.  Therefore the cast to intptr_t is
>+       * needed.
>+       *
>+       * TODO(chadv): Fix this everywhere in i965 by fixing the signature of
>+       * intel_miptree_get_image_offset() to use intptr_t.
>+       */
>+      map->ptr = base + (intptr_t) y * (intptr_t) map->stride
>+                      + (intptr_t) x * (intptr_t) mt->cpp;
>    }
> 
>    DBG("%s: %d,%d %dx%d from mt %p (%s) %d,%d = %p/%d\n", __FUNCTION__,
>-- 
>2.1.2.1.g5433a3e
>

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Attachments on bug 78770: 100086 | 108737 | 108863 | 108978 | 108983 | 109012 | 109076 | 109262

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