Re: [igt-dev] [PATCH i-g-t] tests/kms_big_fb: Add assert for drm_intel_bufmgr and intel_batchbuffer before usage

Sharma, Swati2
2019-09-03T20:10:39Z

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On 13-Aug-19 4:08 PM, Chris Wilson wrote:
> Quoting Ser, Simon (2019-08-13 11:28:54)
>> On Thu, 2019-08-08 at 18:04 +0530, Swati Sharma wrote:
>>> if drm_intel_bufmgr_gem_init() or intel_batchbuffer_alloc()
>>> returns NULL, it leads to seg fault as below:
>>>
>>> root@testrunner:/home/testrunner/swati/otc_gen_graphics-intel-gpu-tools#
>>> ./tests/kms_big_fb
>>> IGT-Version: 1.24-g976db91 (x86_64) (Linux: 5.1.0-rc6+ x86_64)
>>> Max driver framebuffer size 8192x8192
>>> RAM: 2749 MiB, GPU address space: 134217728 MiB, GGTT mappable size: 256
>>> MiB
>>> Received signal SIGSEGV.
>>> Stack trace:
>>> #0 [fatal_sig_handler+0x77]
>>> #1 [killpg+0x40]
>>> #2 [drm_intel_bo_alloc+0x0]
>>> #3 [intel_batchbuffer_reset+0x33]
>>> #4 [intel_batchbuffer_alloc+0x34]
>>> #5 [__real_main603+0x3e9]
>>> #6 [main+0x23]
>>> #7 [__libc_start_main+0xf0]
>>> #8 [_start+0x29]
>>> #9 [<unknown>+0x29]
>>> Segmentation fault (core dumped)
>>>
>>> To prevent this igt_assert() is added for both the functions.
>> I'm not sure I understand why this segfault happens. Seems like
>> drm_intel_bufmgr_gem_init can return NULL in the following cases:
>>
>> * No compiled with libdrm_intel support, in which case the tests should
>> be skipped
>> * Allocation failure or pthread mutex failure, which are unlikely to
>> happen (but it would be nice to log something when those fail)
>> * DRM_IOCTL_I915_GEM_APERTURE fails (but something is printed to
>> stderr, it doesn't seem like this is the case here)
>>
>> Am I missing something?
> Usual cause is unrecognised GPU by libdrm. In which case it should be an
> igt_require_f(data.bufmgr, "Update libdrm for %s support\n", intel_chipset_get_name(devid))
> Roll that up into an <somename>_wrapper and spread far and wide.
> (Although I prefer the option of not using libdrm_intel in the first
> place.)
> -Chris
Shouldn't we add igt_assert() and instead add wrapper func to check bufmgr?

--
~Swati Sharma

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