Bug#196090: gcc-3.3: miscompiles XDM-AUTHORIZATION-1 key validation in XFree86 on PowerPC
Package: gcc-3.3
Version: 1:3.3-2
Severity: important
Tags: upstream, moreinfo
You're going to need more information from me on this, I'm sure, but I'm
filing the bug now so I don't forget to file it at all.
When testing XFree86 4.2.1-7 on my PowerPC I found that compiling the
tree with -O2 (per Debian Policy) and GCC 3.3 caused the X server to
break such that XDM-AUTHORIZATION-1 Xauth tokens could not be validated.
I have not narrowed this down. I do know that using the 4.2.1-6 server
with the 4.2.1-7 libraries worked fine, so I suspect a miscompilation on
the server side, but it is conceivable that the problem is really on the
client/library side and that GCC 3.3 is exposing a very subtle error in
the code. Or something like that.
Compiling with -O instead of -O2 made the problem go away, and that's
the optimization level that was used for the 4.2.1-7 packages for
PowerPC which were uploaded.
Anyway, I have heard rumors that the GCC team knows that there are
problems with this optimization level on PowerPC in GCC 3.3. Something
about a bunch of new subtargets being added to the ppc/ELF backend in
this release?
Please nag me for more information if too much time passes and I have
not followed up.
Alternatively some person might be willing to track this down for me
using the recipe above. Just take the 4.2.1-7 source package and remove
the special case optimization stepdown for powerpc from the debian/rules
file.
Compile XFree86, install the resulting packages, and use xdm to
(attempt) to start a session. You'll also notice that the bustage keeps
the xdm greeter from working properly.
-- System Information:
Debian Release: testing/unstable
Architecture: powerpc
Kernel: Linux redwald 2.4.19-powerpc #1 Mon Sep 9 09:01:43 EDT 2002 ppc
Locale: LANG=C, LC_CTYPE=en_US
Versions of packages gcc-3.3 depends on:
ii binutils 2.14.90.0.4-0.1 The GNU assembler, linker and bina
ii cpp-3.3 1:3.3-2 The GNU C preprocessor
ii gcc-3.3-base 1:3.3-2 The GNU Compiler Collection (base
ii libc6 2.3.1-17 GNU C Library: Shared libraries an
ii libgcc1 1:3.3-2 GCC support library
-- no debconf information
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