[Pkg-games-ubuntu] [Bug 725044] Re: SDL rendering issue: graphic corruption while scrolling right

Sun Mar 13 01:22:36 UTC 2011

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On 2011-03-06T19:08:41+00:00 Richard wrote:

There is an upstream bug report regarding this that contains a patch:

http://bugzilla.libsdl.org/show_bug.cgi?id=1090

Bug #354175 involves a program that is affected by this. Applying the
upstream patch to media-libs/libsdl-1.2.14-r5 resolves it. The following
commands can be used to test the patch:

ebuild $(equery which media-libs/libsdl-1.2.14-r5) prepare
cd /var/tmp/portage/media-libs/libsdl-1.2.14-r5/work/SDL-1.2.14
wget -O - http://bugzilla.libsdl.org/attachment.cgi?id=574 | patch --dry-run -p1
ebuild $(equery which media-libs/libsdl-1.2.14-r5) merge

The other ebuild versions, including the media-libs/libsdl-1.2.13-r1
ebuild used by stable, are also affected. The following commands can be
used to test the patch with media-libs/libsdl-1.2.13-r1:

ebuild $(equery which media-libs/libsdl-1.2.13-r1) prepare
cd /var/tmp/portage/media-libs/libsdl-1.2.13-r1/work/SDL-1.2.13
wget -O - http://bugzilla.libsdl.org/attachment.cgi?id=574 | patch --dry-run -p1
ebuild $(equery which media-libs/libsdl-1.2.13-r1) merge

The reason we are seeing this issue in programs that rely on libsdl now
is because of a change to glibc's memcpy() function late last year. The
old implementation allowed programs to call memcpy() on overlapping
regions. The new implementation copies memory in reverse, which broke
any code that relied on the old implementation. The assumption that
memcpy() works between overlapping regions of memory is illegal under
ANSI C. There is a fairly lengthy bug report at the Fedora Linux bug
tracker about this where Linus Torvalds commented on the issue:

https://bugzilla.redhat.com/show_bug.cgi?id=638477

I recommend inserting media-libs/libsdl-1.2.13-r2 and media-
libs/libsdl-1.2.14-r6 into the portage tree with this patch. I also
strongly recommend removing the existing ebuilds from the portage tree.

Reply at: https://bugs.launchpad.net/libsdl/+bug/725044/comments/2

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On 2011-03-06T19:14:27+00:00 Richard wrote:

I made a small mistake in my previous comment. The commands to test the
application of this patch to unstable should be:

ebuild $(equery which media-libs/libsdl-1.2.14-r5) prepare
cd /var/tmp/portage/media-libs/libsdl-1.2.14-r5/work/SDL-1.2.14
wget -O - http://bugzilla.libsdl.org/attachment.cgi?id=574 | patch -p1
ebuild $(equery which media-libs/libsdl-1.2.14-r5) merge

The commands to test the application of this patch to stable should be:

ebuild $(equery which media-libs/libsdl-1.2.13-r1) prepare
cd /var/tmp/portage/media-libs/libsdl-1.2.13-r1/work/SDL-1.2.13
wget -O - http://bugzilla.libsdl.org/attachment.cgi?id=574 | patch -p1
ebuild $(equery which media-libs/libsdl-1.2.13-r1) merge

Sorry about any confusion my mistake might have caused. I had already
modified the ebuild in a local overlay, so when I was testing these
commands, I had to first reverse the patch and then apply it. I
accidentally copied one of the --dry-run commands I had done during the
course of this and then carried that mistake over the other set I had
posted.

Reply at: https://bugs.launchpad.net/libsdl/+bug/725044/comments/3

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On 2011-03-06T19:23:32+00:00 Richard wrote:

I just noticed that sys-libs/glibc-2.13-r1 is keyworded, so anyone
affected by this is likely using the unstable tree. Please disregard the
instructions I posted for users of the stable tree. As long as they do
not unkeyword glibc, they will likely not need to worry about this.

Reply at: https://bugs.launchpad.net/libsdl/+bug/725044/comments/4

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On 2011-03-06T19:24:26+00:00 Richard wrote:

(In reply to comment #2)
> I just noticed that sys-libs/glibc-2.13-r1 is keyworded, so anyone affected by
> this is likely using the unstable tree. Please disregard the instructions I
> posted for users of the stable tree. As long as they do not unkeyword glibc,
> they will likely not need to worry about this.
> 

Actually disregard comment #2. That was meant for bug #354175. I posted
it in this bug by mistake.

Reply at: https://bugs.launchpad.net/libsdl/+bug/725044/comments/5

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On 2011-03-08T22:10:00+00:00 Mr-bones- wrote:

fixed in libsdl-1.2.14-r6

Reply at: https://bugs.launchpad.net/libsdl/+bug/725044/comments/6

------------------------------------------------------------------------
On 2011-03-09T01:53:06+00:00 Richard wrote:

(In reply to comment #4)
> fixed in libsdl-1.2.14-r6

libsdl-1.2.13-r1 also misuses memcpy(), so you might want to patch it
too. Otherwise, this issue will occur again when glibc-2.13 becomes
stable.

Reply at: https://bugs.launchpad.net/libsdl/+bug/725044/comments/7

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On 2011-03-09T02:24:44+00:00 Mr-bones- wrote:

guess we'll mark the later version of libsdl stable before making
glibc-2.13 stable.

Reply at: https://bugs.launchpad.net/libsdl/+bug/725044/comments/8

** Changed in: gentoo
       Status: Unknown => Fix Released

** Changed in: gentoo
   Importance: Unknown => Medium

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https://bugs.launchpad.net/bugs/725044

Title:
  SDL rendering issue: graphic corruption while scrolling right

Status in Simple Directmedia Layer:
  Unknown
Status in The Battle for Wesnoth:
  Unknown
Status in “libsdl1.2” package in Ubuntu:
  Triaged
Status in “wesnoth-1.8” package in Ubuntu:
  Invalid
Status in “libsdl1.2” source package in Natty:
  Triaged
Status in “wesnoth-1.8” source package in Natty:
  Invalid
Status in Fedora:
  New
Status in Gentoo Linux:
  Fix Released

Bug description:
  Binary package hint: wesnoth-1.8

  using natty 11.04 with latest updates as of today (25.2)

  when playing and scrolling to the right the screen gets corrupted, scrolling up/down/left works as expected
  there is also a screenshot + a small diff available in the wesnoth forums ->
  http://forums.wesnoth.org/viewtopic.php?uid=109471&f=4&t=32423&start=0

  it happens using nouveau and nvidia binary driver..