"Gustavo A. R. Silva" gustavo@embeddedor.com writes:

In preparation to enabling -Wvla, remove VLA. In this particular case use macro ARRAY_SIZE so the length of array _bo_ can be computed at preprocessing time.

The use of stack Variable Length Arrays needs to be avoided, as they can be a vector for stack exhaustion, which can be both a runtime bug or a security flaw. Also, in general, as code evolves it is easy to lose track of how big a VLA can get. Thus, we can end up having runtime failures that are hard to debug.

Also, fixed as part of the directive to remove all VLAs from the kernel: https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Gustavo A. R. Silva gustavo@embeddedor.com

drivers/gpu/drm/vc4/vc4_validate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vc4/vc4_validate.c b/drivers/gpu/drm/vc4/vc4_validate.c index 2db485a..eec76af 100644 --- a/drivers/gpu/drm/vc4/vc4_validate.c +++ b/drivers/gpu/drm/vc4/vc4_validate.c @@ -753,7 +753,7 @@ validate_gl_shader_rec(struct drm_device *dev, 28, /* cs */ }; uint32_t shader_reloc_count = ARRAY_SIZE(shader_reloc_offsets);

• struct drm_gem_cma_object *bo[shader_reloc_count + 8];

• struct drm_gem_cma_object *bo[ARRAY_SIZE(shader_reloc_offsets) + 8]; uint32_t nr_attributes, nr_relocs, packet_size; int i;

-- 2.7.4

It's a shame that the compiler is warning about this when it's obviously a compile-time constant. Regardless, reviewed and applied.