[Mesa-dev] [PATCH] ilo: Ensure array 'shaders' in fully initialized.

[Vinson Lee]

On Fri, May 31, 2013 at 12:35 AM, Chia-I Wu <olvaffe at gmail.com> wrote:
> On Fri, May 31, 2013 at 2:59 PM, Vinson Lee <vlee at freedesktop.org> wrote:
>> Fixes "Uninitialized pointer read" defect reported by Coverity.
> This looks like a false alarm, as shaders are not read when
> num_shaders is zero.  Does the report give more details?
>

    	1. var_decl: Declaring variable "shaders" without initializer.
  86   struct ilo_shader *shaders[PIPE_SHADER_TYPES];
  87   int num_shaders = 0, i;
  88
    	2. Condition "i < 4", taking true branch
    	5. Condition "i < 4", taking true branch
    	8. Condition "i < 4", taking false branch
  89   for (i = 0; i < PIPE_SHADER_TYPES; i++) {
  90      /* no state bound */
    	3. Condition "!sh[i].state", taking true branch
    	6. Condition "!sh[i].state", taking true branch
  91      if (!sh[i].state)
    	4. Continuing loop
    	7. Continuing loop
  92         continue;
  93
  94      /* switch variant if the shader or the states it depends on changed */
  95      if (ilo->dirty & (sh[i].dirty | sh[i].deps)) {
  96         struct ilo_shader_variant variant;
  97
  98         ilo_shader_variant_init(&variant, &sh[i].state->info, ilo);
  99         ilo_shader_state_use_variant(sh[i].state, &variant);
 100      }
 101
 102      shaders[num_shaders++] = sh[i].state->shader;
 103   }
 104    	
    	Uninitialized pointer read (UNINIT)
    	9. uninit_use_in_call: Using uninitialized element of array
"shaders" when calling "ilo_shader_cache_set(struct ilo_shader_cache
*, struct ilo_shader **, int)".
 105   ilo_shader_cache_set(ilo->shader_cache, shaders, num_shaders);
/src/gallium/drivers/ilo/ilo_shader.c
556ilo_shader_cache_set(struct ilo_shader_cache *shc,
557                     struct ilo_shader **shaders,
558                     int num_shaders)
559{
560   int new_cur, i;
561
562   /* calculate the space needed */
563   new_cur = shc->cur;
   	1. Condition "i < num_shaders", taking true branch
564   for (i = 0; i < num_shaders; i++) {
   	2. read_parm: Reading a parameter value.
565      if (shaders[i]->cache_seqno != shc->seqno)
566         new_cur = align(new_cur, 64) + shaders[i]->kernel_size;
567   }


>> Signed-off-by: Vinson Lee <vlee at freedesktop.org>
>> ---
>>  src/gallium/drivers/ilo/ilo_state.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/src/gallium/drivers/ilo/ilo_state.c b/src/gallium/drivers/ilo/ilo_state.c
>> index 33da429..f071292 100644
>> --- a/src/gallium/drivers/ilo/ilo_state.c
>> +++ b/src/gallium/drivers/ilo/ilo_state.c
>> @@ -83,7 +83,7 @@ finalize_shader_states(struct ilo_context *ilo)
>>           .deps = 0,
>>        },
>>     };
>> -   struct ilo_shader *shaders[PIPE_SHADER_TYPES];
>> +   struct ilo_shader *shaders[PIPE_SHADER_TYPES] = { 0 };
>>     int num_shaders = 0, i;
>>
>>     for (i = 0; i < PIPE_SHADER_TYPES; i++) {
>> --
>> 1.8.2.1
>>
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>
>
>
> --
> olv at LunarG.com