This commit breaks the intro memento by conspiracy (http://www.pouet.net/prod.php?which=24472).

Backtrace with git-3330dec:

glretrace: i915_prim_vbuf.c:477: draw_arrays_fallback: Assertion `0' failed.

Program received signal SIGABRT, Aborted.
0xb7fde424 in __kernel_vsyscall ()
(gdb) bt
#0  0xb7fde424 in __kernel_vsyscall ()
#1  0xb7b664d6 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#2  0xb7b69853 in __GI_abort () at abort.c:89
#3  0xb7b5f857 in __assert_fail_base (fmt=0xb7c9a554 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=assertion@entry=0xb7693f8a "0", file=file@entry=0xb775f5b3 "i915_prim_vbuf.c", line=line@entry=477, 
    function=function@entry=0xb775f6ea <__PRETTY_FUNCTION__.9215> "draw_arrays_fallback") at assert.c:92
#4  0xb7b5f907 in __GI___assert_fail (assertion=assertion@entry=0xb7693f8a "0", file=file@entry=0xb775f5b3 "i915_prim_vbuf.c", line=477, function=0xb775f6ea <__PRETTY_FUNCTION__.9215> "draw_arrays_fallback") at assert.c:101
#5  0xb7638d65 in draw_arrays_fallback (nr=<optimized out>, start=<optimized out>, render=<optimized out>) at i915_prim_vbuf.c:477
#6  i915_vbuf_render_draw_arrays (render=0x83a0ff0, start=<optimized out>, nr=4092) at i915_prim_vbuf.c:503
#7  0xb7417cf1 in draw_pt_emit_linear (emit=0x83a1cc0, vert_info=0xbfffeff0, prim_info=0xbffff020) at draw/draw_pt_emit.c:258
#8  0xb75eee7d in emit (prim_info=0xbffff020, vert_info=0xbfffeff0, emit={void (const struct draw_prim_info *, const struct draw_vertex_info *, struct pt_emit *)} 0xb75eedd3 <llvm_middle_end_linear_run+883>) at draw/draw_pt_fetch_shade_pipeline_llvm.c:336
#9  llvm_pipeline_generic (in_prim_info=0xbffff020, fetch_info=0x0, middle=0x83ec5a0) at draw/draw_pt_fetch_shade_pipeline_llvm.c:468
#10 llvm_middle_end_linear_run (middle=0x83ec5a0, start=0, count=4092, prim_flags=0) at draw/draw_pt_fetch_shade_pipeline_llvm.c:532
#11 0xb74207a0 in vsplit_segment_simple_linear (vsplit=0x83d6f90, icount=4092, istart=0, flags=0) at draw/draw_pt_vsplit_tmp.h:240
#12 vsplit_run_linear (frontend=0x83d6f90, start=0, count=4092) at draw/draw_split_tmp.h:60
#13 0xb7416fb7 in draw_pt_arrays (draw=draw@entry=0x840c650, prim=7, start=0, count=count@entry=4092) at draw/draw_pt.c:149
#14 0xb741744a in draw_vbo (draw=0x840c650, info=0xbffff1d0, info@entry=0xbffff2c0) at draw/draw_pt.c:562
#15 0xb762c98e in i915_draw_vbo (pipe=0x83ebc38, info=0xbffff2c0) at i915_context.c:103
#16 0xb73ff258 in cso_draw_vbo (cso=0x8408db0, info=info@entry=0xbffff2c0) at cso_cache/cso_context.c:1400
#17 0xb72d7690 in st_draw_vbo (ctx=0x84b7390, prims=0x84052b4, nr_prims=2, ib=0x0, index_bounds_valid=1 '\001', min_index=0, max_index=4095, tfb_vertcount=0x0, indirect=0x0) at state_tracker/st_draw.c:286
#18 0xb72a238f in vbo_exec_vtx_flush (exec=exec@entry=0x8404f04, keepUnmapped=keepUnmapped@entry=0 '\000') at vbo/vbo_exec_draw.c:409
#19 0xb728d55c in vbo_exec_wrap_buffers (exec=0x8404f04) at vbo/vbo_exec_api.c:89
#20 vbo_exec_vtx_wrap (exec=0x8404f04) at vbo/vbo_exec_api.c:124
#21 0x080b5396 in _glVertex2f(float, float) ()
#22 0x080f9681 in retrace_glVertex2f(trace::Call&) ()
#23 0x0806ce8e in retrace::Retracer::retrace(trace::Call&) ()
#24 0x08063d37 in retrace::retraceCall(trace::Call*) ()
#25 0x08065994 in retrace::RelayRunner::runLeg(trace::Call*) ()
#26 0x0806587c in retrace::RelayRunner::runRace() ()
#27 0x08064053 in retrace::RelayRace::run() ()
#28 0x0806420f in retrace::mainLoop() ()
#29 0x08064985 in main ()


$ git bisect bad
fd33a6bcd7f1271e80332379131e82e00fe10586 is the first bad commit
commit fd33a6bcd7f1271e80332379131e82e00fe10586
Author: José Fonseca <jfonseca@vmware.com>
Date:   Fri Apr 26 08:03:33 2013 +0100

    gallium: Use C11 thread abstractions.
    
    Note that PIPE_ROUTINE now returns an int.
    
    Reviewed-by: Brian Paul <brianp@vmware.com>
    Reviewed-by: Chad Versace <chad.versace@linux.intel.com>

:040000 040000 dec5215b27af2e3f703e701e323dd5fdeba072eb a8b06eaa9746db86fa603a657a7b6a5dcd9e3633 M	src


Reverting this commit on top of master fixes this crash.