[Mesa-dev] Mesa (master): draw: Only run prepare when state, prim and opt changes

Stéphane Marchesin stephane.marchesin at gmail.com
Thu Jan 26 20:27:02 PST 2012


So actually it's a case of a use-after free. The variant is freed with
draw_llvm_destroy_variant and then reused through
llvm_pipeline_generic after free_gallium_state (and llvm) reused the
memory for something else. What prevents a variant bound to an fpme
from being freed by the garbage collection?

Stéphane


2012/1/26 Stéphane Marchesin <stephane.marchesin at gmail.com>:
> I just took a look at it in gdb. Basically the jit_func pointer is
> corrupted by the free_gallivm_state function (in lp_bld_init.c). There
> is a comment to that effect already. It seems like the bug was always
> there but hidden because we regenerated state more than we had to.
> I'll keep digging...
>
> Stéphane
>
>
> 2012/1/26 Stéphane Marchesin <stephane.marchesin at gmail.com>:
>> Hmm, I'll take a look later today.
>>
>> Stéphane
>>
>> 2012/1/26 Jose Fonseca <jfonseca at vmware.com>:
>>> Stephane,
>>>
>>> This commit caused a segmentation fault on glean texSwizzle test + llvmpipe:
>>>
>>> $ gdb --args glean --run results --overwrite --quick --tests texSwizzle
>>> (gdb) r
>>> Starting program: glean --run results --overwrite --quick --tests texSwizzle
>>> [Thread debugging using libthread_db enabled]
>>>
>>> Program received signal SIGSEGV, Segmentation fault.
>>> 0xfffffffffffffffc in ?? ()
>>> (gdb) bt
>>> #0  0xfffffffffffffffc in ?? ()
>>> #1  0x00007ffff6a26438 in llvm_pipeline_generic (middle=0x76e4a0, fetch_info=0x7fffffffd730, prim_info=0x7fffffffd700)
>>>    at src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c:240
>>> #2  0x00007ffff6a266fe in llvm_middle_end_linear_run (middle=0x76e4a0, start=0, count=4, prim_flags=0)
>>>    at src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c:358
>>> #3  0x00007ffff697bf23 in vsplit_segment_simple_linear (vsplit=0x76b670, flags=0, istart=0, icount=4) at src/gallium/auxiliary/draw/draw_pt_vsplit_tmp.h:237
>>> #4  0x00007ffff697c228 in vsplit_run_linear (frontend=0x76b670, start=0, count=4) at src/gallium/auxiliary/draw/draw_split_tmp.h:61
>>> #5  0x00007ffff697224e in draw_pt_arrays (draw=0x762510, prim=6, start=0, count=4) at src/gallium/auxiliary/draw/draw_pt.c:142
>>> #6  0x00007ffff6972eb1 in draw_vbo (draw=0x762510, info=0x7fffffffd910) at src/gallium/auxiliary/draw/draw_pt.c:534
>>> #7  0x00007ffff6689f67 in llvmpipe_draw_vbo (pipe=0x72fa10, info=0x7fffffffd910) at src/gallium/drivers/llvmpipe/lp_draw_arrays.c:85
>>> #8  0x00007ffff68037f4 in st_draw_vbo (ctx=0x7c4b30, arrays=0x831c88, prims=0x7fffffffd9e0, nr_prims=1, ib=0x0, index_bounds_valid=1 '\001', min_index=0,
>>>    max_index=3, tfb_vertcount=0x0) at src/mesa/state_tracker/st_draw.c:1113
>>> #9  0x00007ffff689d811 in vbo_draw_arrays (ctx=0x7c4b30, mode=6, start=0, count=4, numInstances=1) at src/mesa/vbo/vbo_exec_array.c:635
>>> #10 0x00007ffff689d950 in vbo_exec_DrawArrays (mode=6, start=0, count=4) at src/mesa/vbo/vbo_exec_array.c:667
>>> #11 0x0000000000458205 in GLEAN::TexSwizzleTest::TestSwizzles (this=0x6f10e0) at /var/lib/hudson/jobs/glean-ubuntu64/workspace/src/glean/ttexswizzle.cpp:293
>>> #12 0x0000000000458558 in GLEAN::TexSwizzleTest::runOne (this=0x6f10e0, r=..., w=<optimized out>)
>>>    at /var/lib/hudson/jobs/glean-ubuntu64/workspace/src/glean/ttexswizzle.cpp:387
>>> #13 0x0000000000458ec7 in GLEAN::BaseTest<GLEAN::TexSwizzleResult>::run (this=0x6f10e0, environment=<optimized out>)
>>>    at /var/lib/hudson/jobs/glean-ubuntu64/workspace/src/glean/tbase.h:317
>>> #14 0x00000000004610b8 in main (argc=7, argv=0x7fffffffdec8) at /var/lib/hudson/jobs/glean-ubuntu64/workspace/src/glean/main.cpp:140
>>> (gdb)
>>>
>>> Can you look into it?
>>>
>>> Jose
>>>
>>>
>>> ----- Original Message -----
>>>> Module: Mesa
>>>> Branch: master
>>>> Commit: b6d3a435a0e0e53a9e8cc4c4249dc7c2f897a83d
>>>> URL:
>>>>    http://cgit.freedesktop.org/mesa/mesa/commit/?id=b6d3a435a0e0e53a9e8cc4c4249dc7c2f897a83d
>>>>
>>>> Author: Jakob Bornecrantz <wallbraker at gmail.com>
>>>> Date:   Mon Jan 24 02:11:59 2011 +0100
>>>>
>>>> draw: Only run prepare when state, prim and opt changes
>>>>
>>>> In bad applications like ipers which does a lot of draw calls with
>>>> no state changes this helps to greatly reduce time spent in prepare.
>>>> In ipers around 7% of CPU was spent in various prepare functions,
>>>> after this commit no prepare function show on the profile.
>>>>
>>>> This commit also has the added benefit of now grouping all pipelined
>>>> drawing into a single draw call if the driver uses vbuf_render.
>>>>
>>>> Reviewed-by: Stéphane Marchesin <marcheu at chromium.org>
>>>> Tested-by: Stéphane Marchesin <marcheu at chromium.org>
>>>>
>>>> ---
>>>>
>>>>  src/gallium/auxiliary/draw/draw_context.c   |    6 +++
>>>>  src/gallium/auxiliary/draw/draw_private.h   |    8 ++++
>>>>  src/gallium/auxiliary/draw/draw_pt.c        |   49
>>>>  ++++++++++++++++++++++++---
>>>>  src/gallium/auxiliary/draw/draw_pt.h        |    2 +-
>>>>  src/gallium/auxiliary/draw/draw_pt_vsplit.c |   11 ++++--
>>>>  5 files changed, 66 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/src/gallium/auxiliary/draw/draw_context.c
>>>> b/src/gallium/auxiliary/draw/draw_context.c
>>>> index 4ce4445..3c0b1aa 100644
>>>> --- a/src/gallium/auxiliary/draw/draw_context.c
>>>> +++ b/src/gallium/auxiliary/draw/draw_context.c
>>>> @@ -355,6 +355,10 @@ draw_set_vertex_elements(struct draw_context
>>>> *draw,
>>>>  {
>>>>     assert(count <= PIPE_MAX_ATTRIBS);
>>>>
>>>> +   /* We could improve this by only flushing the frontend and the
>>>> fetch part
>>>> +    * of the middle. This would avoid recalculating the emit keys.*/
>>>> +   draw_do_flush( draw, DRAW_FLUSH_STATE_CHANGE );
>>>> +
>>>>     memcpy(draw->pt.vertex_element, elements, count *
>>>>     sizeof(elements[0]));
>>>>     draw->pt.nr_vertex_elements = count;
>>>>  }
>>>> @@ -654,6 +658,8 @@ void draw_do_flush( struct draw_context *draw,
>>>> unsigned flags )
>>>>
>>>>        draw_pipeline_flush( draw, flags );
>>>>
>>>> +      draw_pt_flush( draw, flags );
>>>> +
>>>>        draw->flushing = FALSE;
>>>>     }
>>>>  }
>>>> diff --git a/src/gallium/auxiliary/draw/draw_private.h
>>>> b/src/gallium/auxiliary/draw/draw_private.h
>>>> index 1a0286d..c3eca97 100644
>>>> --- a/src/gallium/auxiliary/draw/draw_private.h
>>>> +++ b/src/gallium/auxiliary/draw/draw_private.h
>>>> @@ -63,6 +63,7 @@ struct draw_stage;
>>>>  struct vbuf_render;
>>>>  struct tgsi_exec_machine;
>>>>  struct tgsi_sampler;
>>>> +struct draw_pt_front_end;
>>>>
>>>>
>>>>  /**
>>>> @@ -137,6 +138,12 @@ struct draw_context
>>>>     /* Support prototype passthrough path:
>>>>      */
>>>>     struct {
>>>> +      /* Current active frontend */
>>>> +      struct draw_pt_front_end *frontend;
>>>> +      unsigned prim;
>>>> +      unsigned opt;
>>>> +      unsigned eltSize; /* saved eltSize for flushing */
>>>> +
>>>>        struct {
>>>>           struct draw_pt_middle_end *fetch_emit;
>>>>           struct draw_pt_middle_end *fetch_shade_emit;
>>>> @@ -391,6 +398,7 @@ void draw_remove_extra_vertex_attribs(struct
>>>> draw_context *draw);
>>>>  boolean draw_pt_init( struct draw_context *draw );
>>>>  void draw_pt_destroy( struct draw_context *draw );
>>>>  void draw_pt_reset_vertex_ids( struct draw_context *draw );
>>>> +void draw_pt_flush( struct draw_context *draw, unsigned flags );
>>>>
>>>>
>>>>  /*******************************************************************************
>>>> diff --git a/src/gallium/auxiliary/draw/draw_pt.c
>>>> b/src/gallium/auxiliary/draw/draw_pt.c
>>>> index 9a017fd..025d539 100644
>>>> --- a/src/gallium/auxiliary/draw/draw_pt.c
>>>> +++ b/src/gallium/auxiliary/draw/draw_pt.c
>>>> @@ -52,7 +52,7 @@ DEBUG_GET_ONCE_BOOL_OPTION(draw_no_fse,
>>>> "DRAW_NO_FSE", FALSE)
>>>>   *     - backend  -- the vbuf_render provided by the driver.
>>>>   */
>>>>  static boolean
>>>> -draw_pt_arrays(struct draw_context *draw,
>>>> +draw_pt_arrays(struct draw_context *draw,
>>>>                 unsigned prim,
>>>>                 unsigned start,
>>>>                 unsigned count)
>>>> @@ -106,17 +106,56 @@ draw_pt_arrays(struct draw_context *draw,
>>>>           middle = draw->pt.middle.general;
>>>>     }
>>>>
>>>> -   frontend = draw->pt.front.vsplit;
>>>> +   frontend = draw->pt.frontend;
>>>> +
>>>> +   if (frontend ) {
>>>> +      if (draw->pt.prim != prim || draw->pt.opt != opt) {
>>>> +         /* In certain conditions switching primitives requires us
>>>> to flush
>>>> +          * and validate the different stages. One example is when
>>>> smooth
>>>> +          * lines are active but first drawn with triangles and then
>>>> with
>>>> +          * lines.
>>>> +          */
>>>> +         draw_do_flush( draw, DRAW_FLUSH_STATE_CHANGE );
>>>> +         frontend = NULL;
>>>> +      } else if (draw->pt.eltSize != draw->pt.user.eltSize) {
>>>> +         /* Flush draw state if eltSize changed.
>>>> +          * This could be improved so only the frontend is flushed
>>>> since it
>>>> +          * converts all indices to ushorts and the fetch part of
>>>> the middle
>>>> +          * always perpares both linear and indexed.
>>>> +          */
>>>> +         frontend->flush( frontend, DRAW_FLUSH_STATE_CHANGE );
>>>> +         frontend = NULL;
>>>> +      }
>>>> +   }
>>>>
>>>> -   frontend->prepare( frontend, prim, middle, opt );
>>>> +   if (!frontend) {
>>>> +      frontend = draw->pt.front.vsplit;
>>>>
>>>> -   frontend->run(frontend, start, count);
>>>> +      frontend->prepare( frontend, prim, middle, opt );
>>>>
>>>> -   frontend->finish( frontend );
>>>> +      draw->pt.frontend = frontend;
>>>> +      draw->pt.eltSize = draw->pt.user.eltSize;
>>>> +      draw->pt.prim = prim;
>>>> +      draw->pt.opt = opt;
>>>> +   }
>>>> +
>>>> +   frontend->run( frontend, start, count );
>>>>
>>>>     return TRUE;
>>>>  }
>>>>
>>>> +void draw_pt_flush( struct draw_context *draw, unsigned flags )
>>>> +{
>>>> +   if (draw->pt.frontend) {
>>>> +      draw->pt.frontend->flush( draw->pt.frontend, flags );
>>>> +
>>>> +      /* don't prepare if we only are flushing the backend */
>>>> +      if (!(flags & DRAW_FLUSH_BACKEND))
>>>> +         draw->pt.frontend = NULL;
>>>> +   }
>>>> +}
>>>> +
>>>> +
>>>>
>>>>  boolean draw_pt_init( struct draw_context *draw )
>>>>  {
>>>> diff --git a/src/gallium/auxiliary/draw/draw_pt.h
>>>> b/src/gallium/auxiliary/draw/draw_pt.h
>>>> index 9a45845..2c2efdc 100644
>>>> --- a/src/gallium/auxiliary/draw/draw_pt.h
>>>> +++ b/src/gallium/auxiliary/draw/draw_pt.h
>>>> @@ -73,7 +73,7 @@ struct draw_pt_front_end {
>>>>                  unsigned start,
>>>>                  unsigned count );
>>>>
>>>> -   void (*finish)( struct draw_pt_front_end * );
>>>> +   void (*flush)( struct draw_pt_front_end *, unsigned flags );
>>>>     void (*destroy)( struct draw_pt_front_end * );
>>>>  };
>>>>
>>>> diff --git a/src/gallium/auxiliary/draw/draw_pt_vsplit.c
>>>> b/src/gallium/auxiliary/draw/draw_pt_vsplit.c
>>>> index c19dcd9..0fed057 100644
>>>> --- a/src/gallium/auxiliary/draw/draw_pt_vsplit.c
>>>> +++ b/src/gallium/auxiliary/draw/draw_pt_vsplit.c
>>>> @@ -178,11 +178,14 @@ static void vsplit_prepare(struct
>>>> draw_pt_front_end *frontend,
>>>>  }
>>>>
>>>>
>>>> -static void vsplit_finish(struct draw_pt_front_end *frontend)
>>>> +static void vsplit_flush(struct draw_pt_front_end *frontend,
>>>> unsigned flags)
>>>>  {
>>>>     struct vsplit_frontend *vsplit = (struct vsplit_frontend *)
>>>>     frontend;
>>>> -   vsplit->middle->finish(vsplit->middle);
>>>> -   vsplit->middle = NULL;
>>>> +
>>>> +   if (!(flags & DRAW_FLUSH_BACKEND)) {
>>>> +      vsplit->middle->finish(vsplit->middle);
>>>> +      vsplit->middle = NULL;
>>>> +   }
>>>>  }
>>>>
>>>>
>>>> @@ -202,7 +205,7 @@ struct draw_pt_front_end *draw_pt_vsplit(struct
>>>> draw_context *draw)
>>>>
>>>>     vsplit->base.prepare = vsplit_prepare;
>>>>     vsplit->base.run     = NULL;
>>>> -   vsplit->base.finish  = vsplit_finish;
>>>> +   vsplit->base.flush   = vsplit_flush;
>>>>     vsplit->base.destroy = vsplit_destroy;
>>>>     vsplit->draw = draw;
>>>>
>>>>
>>>> _______________________________________________
>>>> mesa-commit mailing list
>>>> mesa-commit at lists.freedesktop.org
>>>> http://lists.freedesktop.org/mailman/listinfo/mesa-commit
>>>>


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