Reland "Scrub memory released from a GrMemoryPool in debug mode."
This is a reland of c0315a72d9492f56b4353e269170baaa13d201dc
Original change's description:
> Scrub memory released from a GrMemoryPool in debug mode.
>
> In debug mode, we now overwrite released memory with 0xDD. This is
> intended to make use-after-free errors easier to catch while debugging.
>
> Change-Id: I04a4c5abcfef5f3f604a2430da15a8b5125239af
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/352956
> Auto-Submit: John Stiles <johnstiles@google.com>
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: John Stiles <johnstiles@google.com>
Change-Id: Id79cadb196868b467fb6d9107eb313bdc147b4f0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/353419
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
diff --git a/src/gpu/GrMemoryPool.cpp b/src/gpu/GrMemoryPool.cpp
index 173ff32..7a6b7e6 100644
--- a/src/gpu/GrMemoryPool.cpp
+++ b/src/gpu/GrMemoryPool.cpp
@@ -95,8 +95,6 @@
}
void GrMemoryPool::release(void* p) {
- // NOTE: if we needed it, (p - block) would equal the original alignedOffset value returned by
- // GrBlockAllocator::allocate()
Header* header = reinterpret_cast<Header*>(reinterpret_cast<intptr_t>(p) - sizeof(Header));
#if defined(SK_SANITIZE_ADDRESS)
@@ -112,6 +110,16 @@
#endif
GrBlockAllocator::Block* block = fAllocator.owningBlock<kAlignment>(header, header->fStart);
+
+#if defined(SK_DEBUG)
+ // (p - block) matches the original alignedOffset value from GrBlockAllocator::allocate().
+ intptr_t alignedOffset = (intptr_t)p - (intptr_t)block;
+ SkASSERT(p == block->ptr(alignedOffset));
+
+ // Scrub the block contents to prevent use-after-free errors.
+ memset(p, 0xDD, header->fEnd - alignedOffset);
+#endif
+
int alive = block->metadata();
if (alive == 1) {
// This was last allocation in the block, so remove it
