Fix the way malloc debug returns info.

When I rewrote malloc debug, I accidentally thought that each
value returned in the info buffer contained the number of backtrace
frames in the backtrace. This was incorrect, it should have been
the total number of allocations with the same backtrace.

This is a temporary fix that sets that value to 1. The better fix is
to de-dupe backtraces and then return all allocations of the same size
with the same backtrace.

I updated the documents to describe this.

Bug: 31854476

Test: Unit tests pass.
Change-Id: Idf9efaa3d363923b5d7543d90dc7c65a0ed553d9

1 files changed, 8 insertions, 8 deletions

diff --git a/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp b/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp
index 1b08a39dc..219c21ebb 100644
--- a/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp
+++ b/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp
@@ -999,7 +999,7 @@ TEST_F(MallocDebugTest, get_malloc_leak_info_not_enabled) {
 
 struct InfoEntry {
   size_t size;
-  size_t num_frames;
+  size_t num_allocations;
   uintptr_t frames[0];
 } __attribute__((packed));
 
@@ -1033,7 +1033,7 @@ TEST_F(MallocDebugTest, get_malloc_leak_info_single) {
 
   InfoEntry* entry = reinterpret_cast<InfoEntry*>(expected_info.data());
   entry->size = 200;
-  entry->num_frames = 3;
+  entry->num_allocations = 1;
   entry->frames[0] = 0xf;
   entry->frames[1] = 0xe;
   entry->frames[2] = 0xd;
@@ -1082,7 +1082,7 @@ TEST_F(MallocDebugTest, get_malloc_leak_info_multi) {
 
   // These values will be in the reverse order that we create.
   entry2->size = 500;
-  entry2->num_frames = 4;
+  entry2->num_allocations = 1;
   entry2->frames[0] = 0xf;
   entry2->frames[1] = 0xe;
   entry2->frames[2] = 0xd;
@@ -1097,7 +1097,7 @@ TEST_F(MallocDebugTest, get_malloc_leak_info_multi) {
   memset(pointers[0], 0, entry2->size);
 
   entry1->size = 4100;
-  entry1->num_frames = 16;
+  entry1->num_allocations = 1;
   for (size_t i = 0; i < 16; i++) {
     entry1->frames[i] = 0xbc000 + i;
   }
@@ -1112,7 +1112,7 @@ TEST_F(MallocDebugTest, get_malloc_leak_info_multi) {
   memset(pointers[1], 0, entry1->size);
 
   entry0->size = 9000;
-  entry0->num_frames = 1;
+  entry0->num_allocations = 1;
 
   entry0->frames[0] = 0x104;
   backtrace_fake_add(std::vector<uintptr_t> {0x104});
@@ -1159,7 +1159,7 @@ TEST_F(MallocDebugTest, get_malloc_leak_info_multi_skip_empty_backtrace) {
 
   // These values will be in the reverse order that we create.
   entry1->size = 500;
-  entry1->num_frames = 4;
+  entry1->num_allocations = 1;
   entry1->frames[0] = 0xf;
   entry1->frames[1] = 0xe;
   entry1->frames[2] = 0xd;
@@ -1174,7 +1174,7 @@ TEST_F(MallocDebugTest, get_malloc_leak_info_multi_skip_empty_backtrace) {
   memset(pointers[0], 0, entry1->size);
 
   entry0->size = 4100;
-  entry0->num_frames = 16;
+  entry0->num_allocations = 1;
   for (size_t i = 0; i < 16; i++) {
     entry0->frames[i] = 0xbc000 + i;
   }
@@ -1373,7 +1373,7 @@ static void VerifyZygoteSet(size_t memory_bytes) {
   memset(expected_info.data(), 0, expected_info_size);
   InfoEntry* entry = reinterpret_cast<InfoEntry*>(expected_info.data());
   entry->size = memory_bytes | (1U << 31);
-  entry->num_frames = 1;
+  entry->num_allocations = 1;
   entry->frames[0] = 0x1;
 
   uint8_t* info;