From 1350d79fe162b3380ba9fa86e5395967b2dac467 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Tue, 7 Jan 2025 16:33:43 +0100 Subject: [PATCH] t-reftable-basics: stop assuming that `malloc` is not a constant As indicated by the `#undef malloc` line in `reftable/basics.h`, it is quite common to compile in allocators other than the default one by defining `malloc` constants and friends. This pattern is used e.g. in Git for Windows, which uses the powerful and performant `mimalloc` allocator. Furthermore, in `reftable/basics.c` this `#undef malloc` is _specifically_ disabled by virtue of defining the `REFTABLE_ALLOW_BANNED_ALLOCATORS` constant before including `reftable/basic.h`. However, in 8db127d43f5b (reftable: avoid leaks on realloc error, 2024-12-28) and in 2cca185e8517 (reftable: fix allocation count on realloc error, 2024-12-28), `reftable_set_alloc()` function calls were introduced that pass `malloc`, `realloc` and `free` function pointers as parameters _after_ `reftable/basics.h` ensured that they were no longer `#define`d. This causes problems because those calls happen after the initial allocator has already been used to initialize an array, which is subsequently resized using the overridden default `realloc()` allocator. You cannot mix and match allocators like that, which leads to a `STATUS_HEAP_CORRUPTION` (C0000374), and when running this unit test through shell and/or `prove` (which only support 7-bit status codes), it surfaces as exit code 127. It is totally unnecessary to pass those function pointers to `malloc`/`realloc`/`free` in, though: The `reftable` code goes out of its way to fall back to the initial allocator when passing `NULL` parameters instead. So let's do that instead of causing heap corruptions. Signed-off-by: Johannes Schindelin --- t/unit-tests/t-reftable-basics.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/t/unit-tests/t-reftable-basics.c b/t/unit-tests/t-reftable-basics.c index 990dc1a244..1d640b280f 100644 --- a/t/unit-tests/t-reftable-basics.c +++ b/t/unit-tests/t-reftable-basics.c @@ -157,13 +157,13 @@ int cmd_main(int argc UNUSED, const char *argv[] UNUSED) old_alloc = alloc; old_arr = arr; - reftable_set_alloc(malloc, realloc_stub, free); + reftable_set_alloc(NULL, realloc_stub, NULL); check(REFTABLE_ALLOC_GROW(arr, old_alloc + 1, alloc)); check(arr == old_arr); check_uint(alloc, ==, old_alloc); old_alloc = alloc; - reftable_set_alloc(malloc, realloc, free); + reftable_set_alloc(NULL, NULL, NULL); check(!REFTABLE_ALLOC_GROW(arr, old_alloc + 1, alloc)); check(arr != NULL); check_uint(alloc, >, old_alloc); @@ -188,11 +188,11 @@ int cmd_main(int argc UNUSED, const char *argv[] UNUSED) arr[alloc - 1] = 42; old_alloc = alloc; - reftable_set_alloc(malloc, realloc_stub, free); + reftable_set_alloc(NULL, realloc_stub, NULL); REFTABLE_ALLOC_GROW_OR_NULL(arr, old_alloc + 1, alloc); check(arr == NULL); check_uint(alloc, ==, 0); - reftable_set_alloc(malloc, realloc, free); + reftable_set_alloc(NULL, NULL, NULL); reftable_free(arr); }