[Beignet] runtime_alloc_host_ptr_buffer intermittent failure

[Rebecca N. Palmer]

In beignet 1.0.1 on i5-3230M Debian 8 (libdrm 2.4.58, kernel 
3.16.7-ckt2-1 with the "whitelist OpenCL registers" patch), the recently 
added runtime_alloc_host_ptr_buffer (CL_MEM_ALLOC_HOST_PTR) test often 
fails when run as part of the whole set, but not when run by itself.

The backtrace points to this being a CL_MEM_OBJECT_ALLOCATION_FAILURE. 
(The error handling then calls cl_mem_delete on the incompletely-set-up 
buffer, which fails at assert(mem->ctx).)

$ gdb --args ./utest_run -a
[...]
runtime_use_host_ptr_buffer()    [SUCCESS]
runtime_alloc_host_ptr_buffer()utest_run: 
/home/rnpalmer/Debian/builds/stackbuild/beignet/src/cl_mem.c:1073: 
cl_mem_delete: Assertion `mem->ctx' failed.

Program received signal SIGABRT, Aborted.
0x00007ffff5560107 in raise () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt full
#0  0x00007ffff5560107 in raise () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#1  0x00007ffff55614e8 in abort () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#2  0x00007ffff5559226 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#3  0x00007ffff55592d2 in __assert_fail () from 
/lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#4  0x00007ffff7354be1 in cl_mem_delete (mem=0xf915a0)
     at /home/rnpalmer/Debian/builds/stackbuild/beignet/src/cl_mem.c:1073
         i = <optimized out>
         mem = 0xf915a0
#5  0x00007ffff7354e0b in cl_mem_allocate (type=<optimized out>,
     ctx=<optimized out>, flags=<optimized out>, sz=1638400,
     is_tiled=<optimized out>, host_ptr=<optimized out>, 
errcode=0x7fffffffd754)
     at /home/rnpalmer/Debian/builds/stackbuild/beignet/src/cl_mem.c:339
         bufmgr = <optimized out>
         mem = <optimized out>
         err = -4
         alignment = <optimized out>
         __PRETTY_FUNCTION__ = "cl_mem_allocate"
#6  0x00007ffff7355189 in cl_mem_new_buffer (ctx=0x642d70, flags=16,
     sz=1638400, data=0x0, errcode_ret=0x7fffffffd79c)
---Type <return> to continue, or q <return> to quit---
     at /home/rnpalmer/Debian/builds/stackbuild/beignet/src/cl_mem.c:427
         err = 0
         mem = 0x642d70
         max_mem_size = 1073741824
#7  0x00007ffff73446cf in clCreateBuffer (context=<optimized out>,
     flags=<optimized out>, size=<optimized out>, host_ptr=<optimized out>,
     errcode_ret=0x7fffffffd7bc)
     at /home/rnpalmer/Debian/builds/stackbuild/beignet/src/cl_api.c:489
         mem = 0x0
         err = 0
#8  0x00007ffff776f24c in runtime_alloc_host_ptr_buffer ()
     at 
/home/rnpalmer/Debian/builds/stackbuild/beignet/utests/runtime_alloc_host_ptr_buffer.cpp:10
         status = 0
         __FUNCTION__ = "runtime_alloc_host_ptr_buffer"
         mapptr = <optimized out>
#9  0x00007ffff776f60d in __ANON__runtime_alloc_host_ptr_buffer__ ()
     at 
/home/rnpalmer/Debian/builds/stackbuild/beignet/utests/runtime_alloc_host_ptr_buffer.cpp:25
No locals.
#10 0x00007ffff75a64e1 in UTest::runAll ()