[Bug 8375] New: Odd host-system crashes and texture corruption

[Wine Bugs]

http://bugs.winehq.org/show_bug.cgi?id=8375

Summary: Odd host-system crashes and texture corruption
           Product: Wine
           Version: 0.9.33.
          Platform: Other
        OS/Version: other
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: wine-x11driver
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

First up: this isn't really a Wine-specific bug report, but I'll use it as a
starting point to maybe shed some light on a very odd problem I had on one of my
machines (Athlon X2 system with Nvidia 7900GS graphics card running AMD64
Gentoo) and maybe even help debugging Wine; also, I'd like this problem
documented somewhere, so I'll start with the Wine Bugzilla. Excuse the length,
please, but this isn't easy to describe.
A couple of weeks ago (must have been the weekend of 7/8 Apr 2007), I updated to
xorg-server-1.1.1-r5 (among others; and I always check my system for consistency
with revdep-rebuild after updates) and then tried to continue my FarCry game
(Wine versions I used during this time were 0.9.33 to 0.9.36, which all behaved
the same as far as this call is concerned). I noticed some very strange
artefacts (looked like totally random pixels in textures). Closer inspection
revealed that it was only trees at large distances that were screwed up, once
you got closer and the engine rendered them with more detail, they were OK
again. It may have been just the alpha channel (100% transparent garbage -> no
problem; 0% transparent garbage -> problem). The effect is probably very similar
to the one described in BUG-3918, but pixels were a lot more random for me).
Installation broken? I made a parallel installation of the game and compared all
files of the two trees: all identical. The problem wasn't temperature-related
either, the machine was cold at this time and it didn't change warmed-up either.
OK, so far this sounds a bit like broken RAM or shaders on the video card, but
first up no other games exhibited problems like this (neither native ones like
Doom3/Quake4 at ultra high quality which'll pretty much use up all the card's
memory, nor Wine-emulated, very shader-intensive games like Max Payne II or
Stubbs the Zombie), second the errors always looked the same over engine
restarts and regardless of previous levels (highly unlikely for
broken/uninitialized memory), and third: the current state pretty much rules out
hardware (see below).
Now comes the really unsettling part: when I restarted Wine with FarCry, I
suddenly got a black screen and the machine was dead (not even switching to the
console via Alt-Del-F1 worked any longer, nor did pressing the power button
shutdown the machine; no blinking keyboard LEDs, though, so in all likelihood
not a kernel panic). The only thing that still worked was Alt-SysRq-[SUB]. I
couldn't find anything suspicious in the system logs afterwards, just regular
messages, then my Alt-SysRqs all of a sudden. I think this only happened with
FarCry, but at this time I can't swear it; I can definitely say that no native
software showed any problems with this setup, however. I got this effect two or
three times, then I downgraded to xorg-server-1.1.1-r4 on a hunch and lo and
behold: the crashes were gone. The screwed up tree textures in FarCry remained,
however.
When I upgraded my system the next week, there was a minor update to the Nvidia
driver and some X-libs fixes, but FarCry tree textures remained broken. Then I
upgraded from kernel 2.6.18 to 2.6.20, but I can't tell whether I tried FarCry
in between. Now last week (5/6 May 2007) there was another large bunch of
X-related updates in the Gentoo sync and a bitter pill to swallow:
xorg-server-1.1.1-r4 was no longer in the portage tree, so I had the choice to
try r5 again or downgrade to r0. I decided to give r5 another shot (along with
the rest of the updates) and started FarCry with bated breath and: no crashes.
And you know what? The tree textures were fine again all of a sudden (again,
consistently over engine restarts, and the fix didn't coincide with using a new
Wine version either).
So hardware problems can be pretty much ruled out because hardware doesn't
miraculously heal itself (at least not memory or shaders). xorg-server-1.1.1-r5
in itself probably isn't to blame either because although it obviously
manifested the crashes it now works. I don't even have a clue how the tree
textures can be fixed all of a sudden with just a couple of system upgrades.
Maybe something got screwed up in the 64->32bit emulation libs I have to use on
my system (Wine is compiled as 32bit-app), but even then I find it extremely
unsettling that running a user-space app like Wine (with specific software, i.e.
FarCry) could apparently crash my machine hard. Is it possible that some errors
in programming shaders could crash the card and take the rest of the system with
it? Since I only had crashes and texture problems in Wine, I'd like to use Wine
as a starting point to (hopefully) trace the root of the problem, because I find
it very hard to just forget about it. Maybe other people had this problem too
and can shed some more light on it.
Rejoice, I'm finally done now ;-). Thanks for your time.