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Merge pull request #735 from jsteemann/fix-potential-leak-in-allocate

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prevent potential memleaks in Arena::Allocate*()
This commit is contained in:
Igor Canadi 2015-09-25 12:35:15 -07:00
commit 174e2be5f0
1 changed files with 16 additions and 1 deletions
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17
util/arena.cc
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@ -84,10 +84,12 @@ char* Arena::AllocateFallback(size_t bytes, bool aligned) {
// We waste the remaining space in the current block. // We waste the remaining space in the current block.
size_t size; size_t size;
char* block_head = nullptr; char* block_head = nullptr;
#ifdef MAP_HUGETLB
if (hugetlb_size_) { if (hugetlb_size_) {
size = hugetlb_size_; size = hugetlb_size_;
block_head = AllocateFromHugePage(size); block_head = AllocateFromHugePage(size);
} }
#endif
if (!block_head) { if (!block_head) {
size = kBlockSize; size = kBlockSize;
block_head = AllocateNewBlock(size); block_head = AllocateNewBlock(size);
@ -110,6 +112,11 @@ char* Arena::AllocateFromHugePage(size_t bytes) {
if (hugetlb_size_ == 0) { if (hugetlb_size_ == 0) {
return nullptr; return nullptr;
} }
// already reserve space in huge_blocks_ before calling mmap().
// this way the insertion into the vector below will not throw and we
// won't leak the mapping in that case. if reserve() throws, we
// won't leak either
huge_blocks_.reserve(huge_blocks_.size() + 1);
void* addr = mmap(nullptr, bytes, (PROT_READ | PROT_WRITE), void* addr = mmap(nullptr, bytes, (PROT_READ | PROT_WRITE),
(MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB), 0, 0); (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB), 0, 0);
@ -117,7 +124,8 @@ char* Arena::AllocateFromHugePage(size_t bytes) {
if (addr == MAP_FAILED) { if (addr == MAP_FAILED) {
return nullptr; return nullptr;
} }
huge_blocks_.push_back(MmapInfo(addr, bytes)); // the following shouldn't throw because of the above reserve()
huge_blocks_.emplace_back(MmapInfo(addr, bytes));
blocks_memory_ += bytes; blocks_memory_ += bytes;
return reinterpret_cast<char*>(addr); return reinterpret_cast<char*>(addr);
#else #else
@ -167,6 +175,12 @@ char* Arena::AllocateAligned(size_t bytes, size_t huge_page_size,
} }
char* Arena::AllocateNewBlock(size_t block_bytes) { char* Arena::AllocateNewBlock(size_t block_bytes) {
// already reserve space in blocks_ before allocating memory via new.
// this way the insertion into the vector below will not throw and we
// won't leak the allocated memory in that case. if reserve() throws,
// we won't leak either
blocks_.reserve(blocks_.size() + 1);
char* block = new char[block_bytes]; char* block = new char[block_bytes];
#ifdef ROCKSDB_MALLOC_USABLE_SIZE #ifdef ROCKSDB_MALLOC_USABLE_SIZE
@ -174,6 +188,7 @@ char* Arena::AllocateNewBlock(size_t block_bytes) {
#else #else
blocks_memory_ += block_bytes; blocks_memory_ += block_bytes;
#endif // ROCKSDB_MALLOC_USABLE_SIZE #endif // ROCKSDB_MALLOC_USABLE_SIZE
// the following shouldn't throw because of the above reserve()
blocks_.push_back(block); blocks_.push_back(block);
return block; return block;
} }