Merge "Fix bug in dlmalloc's version of calloc."
diff --git a/libc/upstream-dlmalloc/malloc.c b/libc/upstream-dlmalloc/malloc.c
index 3c9d36b..a61c0da 100644
--- a/libc/upstream-dlmalloc/malloc.c
+++ b/libc/upstream-dlmalloc/malloc.c
@@ -4822,8 +4822,13 @@
req = MAX_SIZE_T; /* force downstream failure on overflow */
}
mem = dlmalloc(req);
- if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
- memset(mem, 0, req);
+ if (mem != 0) {
+ mchunkptr p = mem2chunk(mem);
+ if (calloc_must_clear(p)) {
+ /* Make sure to clear all of the buffer, not just the requested size. */
+ memset(mem, 0, chunksize(p) - overhead_for(p));
+ }
+ }
return mem;
}
diff --git a/tests/malloc_test.cpp b/tests/malloc_test.cpp
index b76625a..5af5a6f 100644
--- a/tests/malloc_test.cpp
+++ b/tests/malloc_test.cpp
@@ -372,3 +372,22 @@
}
#endif
}
+
+TEST(malloc, calloc_usable_size) {
+ for (size_t size = 1; size <= 2048; size++) {
+ void* pointer = malloc(size);
+ ASSERT_TRUE(pointer != nullptr);
+ memset(pointer, 0xeb, malloc_usable_size(pointer));
+ free(pointer);
+
+ // We should get a previous pointer that has been set to non-zero.
+ // If calloc does not zero out all of the data, this will fail.
+ uint8_t* zero_mem = reinterpret_cast<uint8_t*>(calloc(1, size));
+ ASSERT_TRUE(pointer != nullptr);
+ size_t usable_size = malloc_usable_size(zero_mem);
+ for (size_t i = 0; i < usable_size; i++) {
+ ASSERT_EQ(0, zero_mem[i]) << "Failed at allocation size " << size << " at byte " << i;
+ }
+ free(zero_mem);
+ }
+}