[Mesa-dev] [PATCH] virgl: fix flushing while removing sampler views

[marcandre.lureau at redhat.com]

From: Marc-André Lureau <marcandre.lureau at redhat.com>

When updating the sampler views, virgl might need to flush. After
flushing, the resources are reattached, however, the sampler
enabled_mask isn't yet updated, and some views could be in the process
of being removed, which lead to the following crash:

 Thread 1 "heaven_x64" received signal SIGSEGV, Segmentation fault.
 0x00007f83893cc3de in virgl_attach_res_sampler_views (vctx=vctx at entry=0x1c22c00, shader_type=shader_type at entry=1) at virgl_context.c:113
 113          res = virgl_resource(tinfo->views[i]->base.texture);
 (gdb) bt
 #0  0x00007f83893cc3de in virgl_attach_res_sampler_views (vctx=vctx at entry=0x1c22c00, shader_type=shader_type at entry=1) at virgl_context.c:113
 #1  0x00007f83893cc703 in virgl_reemit_res (vctx=0x1c22c00) at virgl_context.c:182
 #2  virgl_flush_eq (ctx=ctx at entry=0x1c22c00, closure=0x1c22c00) at virgl_context.c:637
 #3  0x00007f83893ccbf8 in virgl_flush_from_st (ctx=0x1c22c00, fence=<optimized out>, flags=<optimized out>) at virgl_context.c:659
 #4  0x00007f83893cd6b0 in virgl_encoder_write_cmd_dword (ctx=ctx at entry=0x1c22c00, dword=dword at entry=67075) at virgl_encode.c:43
 #5  0x00007f83893cd76b in virgl_encode_delete_object (ctx=0x1c22c00, handle=1306480, object=object at entry=6) at virgl_encode.c:72
 #6  0x00007f83893ccc81 in virgl_destroy_sampler_view (ctx=<optimized out>, view=0x7aca1b0) at virgl_context.c:741
 #7  0x00007f83893cca17 in pipe_sampler_view_reference (view=0x0, ptr=0x1c22fc8) at ../../../../src/gallium/auxiliary/util/u_inlines.h:151
 #8  virgl_set_sampler_views (ctx=0x1c22c00, shader_type=1, start_slot=<optimized out>, num_views=<optimized out>, views=<optimized out>) at virgl_context.c:724
 #9  0x00007f8388fffd68 in cso_set_sampler_views (ctx=0x1ca2ee0, shader_stage=<optimized out>, count=9, views=<optimized out>) at cso_cache/cso_context.c:1301
 #10 0x00007f8388e670c1 in update_textures (st=<optimized out>, mesa_shader=<optimized out>, prog=<optimized out>, max_units=16, sampler_views=0x1c8c140, num_textures=0x1c8c644) at state_tracker/st_atom_texture.c:465
 #11 0x00007f8388e6296d in st_validate_state (st=st at entry=0x1c8a710, pipeline=pipeline at entry=ST_PIPELINE_RENDER) at state_tracker/st_atom.c:289
 #12 0x00007f8388e8343b in st_draw_vbo (ctx=0x1c50600, prims=0x7ffe99b5a580, nr_prims=1, ib=0x7ffe99b5a560, index_bounds_valid=<optimized out>, min_index=<optimized out>, max_index=<optimized out>, tfb_vertcount=0x0, stream=0,
     indirect=0x0) at state_tracker/st_draw.c:176
 #13 0x00007f8388e44d34 in vbo_validated_drawrangeelements (ctx=ctx at entry=0x1c50600, mode=mode at entry=4, index_bounds_valid=index_bounds_valid at entry=0 '\000', start=start at entry=4294967295, end=end at entry=4294967295, count=count at entry=2688,
     type=5123, indices=0x0, basevertex=0, numInstances=1, baseInstance=0) at vbo/vbo_exec_array.c:849
 #14 0x00007f8388e44db5 in vbo_exec_DrawElementsInstanced (mode=4,
 #count=2688, type=5123, indices=0x0, numInstances=1) at
 #vbo/vbo_exec_array.c:1030

Instead, remove the views from enabled_mask immediately.

Signed-off-by: Marc-André Lureau <marcandre.lureau at redhat.com>
---
 src/gallium/drivers/virgl/virgl_context.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/virgl/virgl_context.c b/src/gallium/drivers/virgl/virgl_context.c
index 9007583..55144d5 100644
--- a/src/gallium/drivers/virgl/virgl_context.c
+++ b/src/gallium/drivers/virgl/virgl_context.c
@@ -711,6 +711,7 @@ static void virgl_set_sampler_views(struct pipe_context *ctx,
       pipe_sampler_view_reference((struct pipe_sampler_view **)&tinfo->views[i], NULL);
    }
 
+   tinfo->enabled_mask &= ~disable_mask;
    for (i = 0; i < num_views; i++) {
       struct virgl_sampler_view *grview = virgl_sampler_view(views[i]);
 
@@ -721,12 +722,11 @@ static void virgl_set_sampler_views(struct pipe_context *ctx,
          new_mask |= 1 << i;
          pipe_sampler_view_reference((struct pipe_sampler_view **)&tinfo->views[i], views[i]);
       } else {
+         tinfo->enabled_mask &= ~(1 << i);
          pipe_sampler_view_reference((struct pipe_sampler_view **)&tinfo->views[i], NULL);
-         disable_mask |= 1 << i;
       }
    }
 
-   tinfo->enabled_mask &= ~disable_mask;
    tinfo->enabled_mask |= new_mask;
    virgl_encode_set_sampler_views(vctx, shader_type, start_slot, num_views, tinfo->views);
    virgl_attach_res_sampler_views(vctx, shader_type);
-- 
2.10.0