https://bugs.freedesktop.org/show_bug.cgi?id=86043

--- Comment #2 from Gavin Graham me@gavingraham.me --- (In reply to Tobias Klausmann from comment #1)

Works fine on my Optimus machine with libdrm 2.4.58. Dota2 runs fine on both GPUs! I am not using bumblebee or primus, so i guess the problem lies there!

Anyway, keeping this bug open for a while.

Out of curiosity, what version nVidia driver are you using?

https://bugs.freedesktop.org/show_bug.cgi?id=86043

--- Comment #4 from Niek Bergman niekbergman@gmail.com --- Can confirm this issue locally on my current system.

Running Steam through the "primusrun" Bumblebee wrapper to start games on the nVidia card leads to the following error after starting a game:

malloc: unknown:0: assertion botched free: called with unallocated block argument last command: (null) Aborting...Aborted (core dumped)

I can also confirm that downgrading libdrm-intel1 to 2.4.56 fixes the issue and allows the game to run on the nVidia card just fine. Furthermore, starting Steam without "primusrun" (thereby causing the game to start on the Intel card) also does not cause this issue.

Should any testing be desired, I'd be happy to oblige.

https://bugs.freedesktop.org/show_bug.cgi?id=86043

--- Comment #6 from Emil Velikov emil.l.velikov@gmail.com --- Guys can you bisect this ? Afaics it will take ~6 steps to track the issue.

https://bugs.freedesktop.org/show_bug.cgi?id=86043

Emil Velikov emil.l.velikov@gmail.com changed:

What |Removed |Added ---------------------------------------------------------------------------- CC| |tvrtko.ursulin@linux.intel. | |com

--- Comment #8 from Emil Velikov emil.l.velikov@gmail.com --- Adding the author to the CC list.

Vedran thanks for bisecting this :-) I'm not sure how this patch can cause such an issue. Either something funny has happened during bisect or there is another underlying problem.

Summary of the problem so far:

Optimus system running Intel mesa and the proprietary Nvidia drivers. Running Steam (games) with either bumblebee, optirun or primusrun seems to cause a crash.

Steam Log: Game update: AppID 550 "Left 4 Dead 2", ProcID 9399, IP 0.0.0.0:0 ... malloc: unknown:0: assertion botched free: called with unallocated block argument last command: (null) Aborting...Game removed: AppID 550 "Left 4 Dead 2", ProcID 9399

Bisecting libdrm shows ae8edc7544e as the offending commit.

If an Intel dev has a similar machine they can try to reproduce it locally. Otherwise a back-trace should help at least a bit.

I while back I was able to use gdb with steam. Not sure if it still works * Close all steam games and the steam client * $ export GAME_DEBUGGER=gdb * $ steam

Note I'm not looking into the issue, just trying to get some information for the Intel devs.

https://bugs.freedesktop.org/show_bug.cgi?id=86043

--- Comment #10 from Vedran Rodic vrodic@gmail.com --- I don't have pre 3.16 kernel easily available.

export GAME_DEBUGGER=gdb still makes the game crash before it runs it with the debugger.

I've tried various things to make it work (modifying the game startup shell script) but without success.

When I put the older version of libdrm (86b37c61c78edd1353a3f76f678c39e2ec168771, before Tvrtkos change), gdb runs normally for the game. So the steam binary actually crashes, not the game itself.

It's funny because steam binary is 32bit, Dota 2 binary is 64 bit, and only changing the 64bit version of libdrm_intel.so affects this bug.

I've tried debugging steam with export DEBUGGER=gdb, but it seems spawn multiple threads and I'm not experienced with multithreaded debugging.

I did manage to run steam with valgrind, I'll add an attachment now.

https://bugs.freedesktop.org/show_bug.cgi?id=86043

--- Comment #12 from Tvrtko Ursulin tvrtko.ursulin@linux.intel.com --- I think we'll need to pull in someone from Steam since Valgrind reports some mismatched frees in vgui2_s.so, steamclient.so and steamui.so.

There are not debug symbols so impossible to guess what area of the code is that.

Then this also looks pretty bad:

ERROR: ld.so: object '/home/vedran/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored. ERROR: ld.so: object '/home/vedran/.local/share/Steam/ubuntu12_32/gameoverlayrenderer.so' from LD_PRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored

Please if someone knows any Steam devs CC them here?

https://bugs.freedesktop.org/show_bug.cgi?id=86043

--- Comment #14 from Chris Wilson chris@chris-wilson.co.uk --- (In reply to Emil Velikov from comment #13)

• Invalid memory access in various modules - invalid reads in various steam

runtime components, alarming number of invalid writes in i965_dri.so.

The latter one perhaps should be looked into closer ?

Probably not, that is just valgrind not understanding GEM and its ioctls. You need to use a libdrm compiled with --enable-valgrind to suppress the false positives.