Skip to content

vkd3d-shader: Return a valid pointer when count=0 in param allocator (ubsan).

Francisco Casas requested to merge fcasas/vkd3d:fix_allocator_count0 into master

After compiling and linking with -fsanitize=undefined the following error pops up in many tests:

vkd3d_shader_main.c:2024:12: runtime error: member access within null pointer of type 'struct vkd3d_shader_param_node'

This happens in the scenario where shader_param_allocator_get() gets called with count = 0 but no allocation has been made yet, so allocator->current is NULL.

In this case the result of the function, given by:

params = &allocator->current->param[allocator->index * allocator->stride];

is an invalid non-NULL pointer.

We can't just return NULL on count == 0, because NULL is interpreted as a memory allocation failure on the callers. So we force allocation of the next node even if count = 0 when allocator->current is NULL.

Thanks @vitorhnn for showing me ubsan!

Merge request reports