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1847a1e8c6
- The current implementation of the topology detector establishes
a contingency, wherein it is expected that the parallel region
uses all the threads queried through omp_get_max_threads(). In
case the actual parallelism in the function is limited(lower than
this expectation), the code may access unallocated memory section
(using uninitialized pointers).
- This was because every thread(having it's own pointer), sets its
initial value to NULL inside the parallel section, thereby leaving
some pointers uninitialized if the associated thread is not spawned.
- Also, the current implementation would use negative indexing(with -1)
if any associated thread was not spawned.
- Fix : Set every thread-specific pointer to NULL outside the parallel
region, using calloc(). As long as we have NULL checks for pointers
before accessing through them, no issues will be observed. Avoid
incurring the topology detection cost if all the reuqired threads
are not spawned(thereby avoiding potential negative indexing).
(when using core-group ID).
AMD-Internal: [SWLCSG-3573]
Co-authored-by: Vignesh Balasubramanian <vignbala@amd.com>
Co-authored-by: Bhaskar, Nallani <Nallani.Bhaskar@amd.com>