severity 663514 serious reassign 663514 src:sdlgfx found 663514 2.0.23-1 tags 663514 patch user ubuntu-de...@lists.ubuntu.com usertags 663514 ubuntu-patch quantal thanks
Hi there, > This package FTBFS on my Xen and KVM based VMs on i386 (but not amd64): The problem is definitely not specific to Xen/KVM. An i386 chroot on an Ubuntu system shows the same build failure: https://bugs.launchpad.net/debian/+source/libsdl-perl/+bug/1029981 The problem is that the cpuFlags() function used for querying cpuid is returning garbage data from the stack. So the sdl-perl test suite passes if the garbage returned happens to not have the MMX bit set both times, and otherwise it fails. I've done some analysis on the linked Ubuntu bug, showing the bug in the disassembled binary, and uploaded a fixed package to Ubuntu which I've confirmed detects mmx support properly and lets libsdl-perl's test suite pass reliably. The attached patch should be suitable for uploading to Debian as well. Please consider applying it at your earliest convenience, or let me know if you would like me to NMU instead. Since this bug in practice causes libsdl-perl to not be reliably rebuildable (more precisely, causes its buildability to depend entirely on random unrelated permutations of the stack, which may change over the lifetime of wheezy), I'm marking this bug as 'serious' for the release. Thanks, -- Steve Langasek Give me a lever long enough and a Free OS Debian Developer to set it on, and I can move the world. Ubuntu Developer http://www.debian.org/ slanga...@ubuntu.com vor...@debian.org
=== modified file 'debian/changelog' --- old/debian/changelog 2011-12-30 20:55:51 +0000 +++ new/debian/changelog 2012-07-31 08:25:59 +0000 @@ -1,3 +1,12 @@ +sdlgfx (2.0.23-1.1) UNRELEASED; urgency=high + + * Non-maintainer upload. + * High-urgency upload for RC bugfix. + * debian/patches/wrong-cpuid-mmx-detection.patch: fix mmx cpuid + detection. Closes: #663514, LP: #1029981. + + -- Steve Langasek <vor...@debian.org> Tue, 31 Jul 2012 01:21:22 -0700 + sdlgfx (2.0.23-1) unstable; urgency=low [ Felix Geyer ] === modified file 'debian/patches/series' --- old/debian/patches/series 2009-04-30 14:34:05 +0000 +++ new/debian/patches/series 2012-07-31 08:25:27 +0000 @@ -1 +1,2 @@ 010_primitives_spell.diff +wrong-cpuid-mmx-detection.patch === added file 'debian/patches/wrong-cpuid-mmx-detection.patch' --- old/debian/patches/wrong-cpuid-mmx-detection.patch 1970-01-01 00:00:00 +0000 +++ new/debian/patches/wrong-cpuid-mmx-detection.patch 2012-07-31 08:25:27 +0000 @@ -0,0 +1,35 @@ +Description: fix mmx cpuid detection + The MMX detection in SDL_imageFilter.c contains buggy assembly which reads + garbage values off the stack. This usually results in MMX not being used + on i386; sometimes it instead causes the test suite to fail. At runtime it + could also cause MMX instructions to be used on non-MMX machines. + . + Replace this cpu detection code with code that doesn't rely on the stack + pointer staying the same after popa. +Author: Steve Langasek <steve.langa...@canonical.com> +Bug: http://sourceforge.net/support/tracker.php?aid=3550046 +Bug-Debian: http://bugs.debian.org/663514 +Bug-Ubuntu: https://launchpad.net/bugs/1029981 + +Index: sdlgfx-2.0.23/SDL_imageFilter.c +=================================================================== +--- sdlgfx-2.0.23.orig/SDL_imageFilter.c ++++ sdlgfx-2.0.23/SDL_imageFilter.c +@@ -80,12 +80,12 @@ + popa + } + #else +- asm volatile ("pusha \n\t" "mov %1, %%eax \n\t" /* request feature flag */ ++ asm volatile ("pusha \n\t" "mov %0, %%eax \n\t" /* request feature flag */ + "cpuid \n\t" /* get CPU ID flag */ +- "mov %%edx, %0 \n\t" /* move result to mmx_bit */ +- "popa \n\t":"=m" (flags) /* %0 */ +- :"i"(0x00000001) /* %1 */ +- ); ++ "mov %%edx, 0(%1) \n\t" /* move result to mmx_bit */ ++ "popa \n\t": ++ :"i"(0x00000001), "S"(&flags) /* %0, %1 */ ++ : "memory"); + #endif + #endif +
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