hello there, i'm having the same issue and i recompiled mesa with debugging
symbols.
i'm using mesa-9.2.0_rc1 on gentoo.
i attached gdb and i found that the issue is at
src/gallium/drivers/r600/r600_query.c:743.

735     void r600_init_query_functions(struct r600_context *rctx)
736     {
737             rctx->context.create_query = r600_create_query;
738             rctx->context.destroy_query = r600_destroy_query;
739             rctx->context.begin_query = r600_begin_query;
740             rctx->context.end_query = r600_end_query;
741             rctx->context.get_query_result = r600_get_query_result;
742
743             if (rctx->screen->info.r600_num_backends > 0)

breaking gdb on line 743 i got this: http://pastebin.com/A4JANB5F

as you can see rctx->screen is null ( 0x0 ), please, can you fix that?

i hope this helps.