Re: [igt-dev] [PATCH i-g-t v3] lib/igt_kms: Fix memory corruption

[Daniel Stone <daniels@collabora.com>]

Hi Vignesh,

On 08/11/2023 06:29, Vignesh Raman wrote:
> In crosvm

Strictly speaking, the change is in virtio-gpu (the kernel driver 
providing KMS), not crosvm (the KVM host for the kernel), but this is an 
unimportant detail.


> , the kernel reports 16 for count_crtcs, which exceeds
> IGT_MAX_PIPES set to 8. The function igt_display_require allocates
> memory for IGT_MAX_PIPES members of igt_pipe_t structures, but then
> writes into it based on the count_crtcs reported by the kernel,
> resulting in memory corruption.
>
>   [...]
>   # Received signal SIGABRT.
>   # Stack trace:
>   #  #0 [fatal_sig_handler+0x17b]
>   #  #1 [__sigaction+0x40]
>   #  #2 [pthread_key_delete+0x14c]
>   #  #3 [gsignal+0x12]
>   #  #4 [abort+0xd3]
>   #  #5 [__fsetlocking+0x290]
>   #  #6 [timer_settime+0x37a]
>   #  #7 [__default_morecore+0x1f1b]
>   #  #8 [__libc_calloc+0x161]
>   #  #9 [drmModeGetPlaneResources+0x44]
>   #  #10 [igt_display_require+0x194]
>   #  #11 [__igt_unique____real_main1356+0x93c]
>   #  #12 [main+0x3f]
>   #  #13 [__libc_init_first+0x8a]
>   #  #14 [__libc_start_main+0x85]
>   #  #15 [_start+0x21]
>
> Increase IGT_MAX_PIPES to 16 to fix this memory corruption issue.
> igt_display_require initializes display and allocate resources as
> a prerequisite for the tests. Fail the test if count_crtcs exceeds
> IGT_MAX_PIPES with debug information.
>
> This fix is required for drm-ci to run igt tests on virtio-gpu.

The rest is all good though, so this change is:
Reviewed-by: Daniel Stone <daniels@collabora.com>

Thanks,
Daniel