[PATCH bpf-next] selftests/bpf: Rename libarena malloc/free methods

[PATCH bpf-next] selftests/bpf: Rename libarena malloc/free methods

[Emil Tsalapatis]

From: Emil Tsalapatis <emil@etsalapatis.com>

The s390 architecture uses the token "free" for an enum, conflicting
with the malloc/free definitions. Rename the calls to arena_malloc and
arena_free instead to prevent collisions.

Reported-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Emil Tsalapatis <etsal@meta.com>
Fixes: 7c8d208d816d0504aa916138ae097d9cb4ed4e56 ("Introduce arena library and runtime)
---
 tools/testing/selftests/bpf/libarena/Makefile               | 2 --
 .../selftests/bpf/libarena/include/libarena/common.h        | 6 +++---
 tools/testing/selftests/bpf/libarena/src/common.bpf.c       | 4 ++--
 3 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/bpf/libarena/Makefile b/tools/testing/selftests/bpf/libarena/Makefile
index 3c695f9c0054..5e2ab514805e 100644
--- a/tools/testing/selftests/bpf/libarena/Makefile
+++ b/tools/testing/selftests/bpf/libarena/Makefile
@@ -51,8 +51,6 @@ ASAN_FLAGS += -mllvm -asan-destructor-kind=none
 override BPF_CFLAGS += -DENABLE_ATOMICS_TESTS
 override BPF_CFLAGS += -O2 -g
 override BPF_CFLAGS += -Wno-incompatible-pointer-types-discards-qualifiers
-# Required to define our own arena-based free()
-override BPF_CFLAGS += -Wno-incompatible-library-redeclaration
 # Required for suppressing harmless vmlinux.h-related warnings.
 override BPF_CFLAGS += -Wno-missing-declarations
 override BPF_CFLAGS += $(INCLUDES)
diff --git a/tools/testing/selftests/bpf/libarena/include/libarena/common.h b/tools/testing/selftests/bpf/libarena/include/libarena/common.h
index e54cb7b869bd..ca1a6c1d6477 100644
--- a/tools/testing/selftests/bpf/libarena/include/libarena/common.h
+++ b/tools/testing/selftests/bpf/libarena/include/libarena/common.h
@@ -48,9 +48,9 @@ extern volatile u64 asan_violated;
 
 int arena_fls(__u64 word);
 
-u64 malloc_internal(size_t size);
-#define malloc(size) ((void __arena *)malloc_internal((size)))
-void free(void __arena *ptr);
+u64 arena_malloc_internal(size_t size);
+#define arena_malloc(size) ((void __arena *)arena_malloc_internal((size)))
+void arena_free(void __arena *ptr);
 
 /*
  * The verifier associates arenas with programs by checking LD.IMM
diff --git a/tools/testing/selftests/bpf/libarena/src/common.bpf.c b/tools/testing/selftests/bpf/libarena/src/common.bpf.c
index e5da1e37e83e..544bf9e1cb38 100644
--- a/tools/testing/selftests/bpf/libarena/src/common.bpf.c
+++ b/tools/testing/selftests/bpf/libarena/src/common.bpf.c
@@ -38,12 +38,12 @@ __weak int arena_buddy_reset(void)
 	return buddy_init(&buddy);
 }
 
-__weak u64 malloc_internal(size_t size)
+__weak u64 arena_malloc_internal(size_t size)
 {
 	return buddy_alloc_internal(&buddy, size);
 }
 
-__weak void free(void __arg_arena __arena *ptr)
+__weak void arena_free(void __arg_arena __arena *ptr)
 {
 	buddy_free_internal(&buddy, (u64)ptr);
 }
-- 
2.52.0

Re: [PATCH bpf-next] selftests/bpf: Rename libarena malloc/free methods

[Ihor Solodrai]

On 4/28/26 2:42 PM, Emil Tsalapatis wrote:
> From: Emil Tsalapatis <emil@etsalapatis.com>
> 
> The s390 architecture uses the token "free" for an enum, conflicting
> with the malloc/free definitions. Rename the calls to arena_malloc and
> arena_free instead to prevent collisions.
> 
> Reported-by: Ihor Solodrai <ihor.solodrai@linux.dev>
> Signed-off-by: Emil Tsalapatis <etsal@meta.com>
> Fixes: 7c8d208d816d0504aa916138ae097d9cb4ed4e56 ("Introduce arena library and runtime)

Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>

> ---
>  tools/testing/selftests/bpf/libarena/Makefile               | 2 --
>  .../selftests/bpf/libarena/include/libarena/common.h        | 6 +++---
>  tools/testing/selftests/bpf/libarena/src/common.bpf.c       | 4 ++--
>  3 files changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/libarena/Makefile b/tools/testing/selftests/bpf/libarena/Makefile
> index 3c695f9c0054..5e2ab514805e 100644
> --- a/tools/testing/selftests/bpf/libarena/Makefile
> +++ b/tools/testing/selftests/bpf/libarena/Makefile
> @@ -51,8 +51,6 @@ ASAN_FLAGS += -mllvm -asan-destructor-kind=none
>  override BPF_CFLAGS += -DENABLE_ATOMICS_TESTS
>  override BPF_CFLAGS += -O2 -g
>  override BPF_CFLAGS += -Wno-incompatible-pointer-types-discards-qualifiers
> -# Required to define our own arena-based free()
> -override BPF_CFLAGS += -Wno-incompatible-library-redeclaration
>  # Required for suppressing harmless vmlinux.h-related warnings.
>  override BPF_CFLAGS += -Wno-missing-declarations
>  override BPF_CFLAGS += $(INCLUDES)
> diff --git a/tools/testing/selftests/bpf/libarena/include/libarena/common.h b/tools/testing/selftests/bpf/libarena/include/libarena/common.h
> index e54cb7b869bd..ca1a6c1d6477 100644
> --- a/tools/testing/selftests/bpf/libarena/include/libarena/common.h
> +++ b/tools/testing/selftests/bpf/libarena/include/libarena/common.h
> @@ -48,9 +48,9 @@ extern volatile u64 asan_violated;
>  
>  int arena_fls(__u64 word);
>  
> -u64 malloc_internal(size_t size);
> -#define malloc(size) ((void __arena *)malloc_internal((size)))
> -void free(void __arena *ptr);
> +u64 arena_malloc_internal(size_t size);
> +#define arena_malloc(size) ((void __arena *)arena_malloc_internal((size)))
> +void arena_free(void __arena *ptr);
>  
>  /*
>   * The verifier associates arenas with programs by checking LD.IMM
> diff --git a/tools/testing/selftests/bpf/libarena/src/common.bpf.c b/tools/testing/selftests/bpf/libarena/src/common.bpf.c
> index e5da1e37e83e..544bf9e1cb38 100644
> --- a/tools/testing/selftests/bpf/libarena/src/common.bpf.c
> +++ b/tools/testing/selftests/bpf/libarena/src/common.bpf.c
> @@ -38,12 +38,12 @@ __weak int arena_buddy_reset(void)
>  	return buddy_init(&buddy);
>  }
>  
> -__weak u64 malloc_internal(size_t size)
> +__weak u64 arena_malloc_internal(size_t size)
>  {
>  	return buddy_alloc_internal(&buddy, size);
>  }
>  
> -__weak void free(void __arg_arena __arena *ptr)
> +__weak void arena_free(void __arg_arena __arena *ptr)
>  {
>  	buddy_free_internal(&buddy, (u64)ptr);
>  }

Re: [PATCH bpf-next] selftests/bpf: Rename libarena malloc/free methods

[bot+bpf-ci]

[-- Attachment #1: Type: text/plain, Size: 709 bytes --]

> Fixes: 7c8d208d816d0504aa916138ae097d9cb4ed4e56 ("Introduce arena library and runtime)

The Fixes: tag points to a merge commit, but kernel convention prefers
pointing to the specific commit that introduced the problematic code.

The malloc/free function definitions that conflict with s390 architecture
were directly introduced by commit 86426a28c52d ("selftests/bpf: Add buddy
allocator for libarena").

Should the Fixes: tag point to commit 86426a28c52d instead?


---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

CI run summary: https://github.com/kernel-patches/bpf/actions/runs/25057261385

Re: [PATCH bpf-next] selftests/bpf: Rename libarena malloc/free methods

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Tue, 28 Apr 2026 06:42:52 -0700 you wrote:
> From: Emil Tsalapatis <emil@etsalapatis.com>
> 
> The s390 architecture uses the token "free" for an enum, conflicting
> with the malloc/free definitions. Rename the calls to arena_malloc and
> arena_free instead to prevent collisions.
> 
> Reported-by: Ihor Solodrai <ihor.solodrai@linux.dev>
> Signed-off-by: Emil Tsalapatis <etsal@meta.com>
> Fixes: 7c8d208d816d0504aa916138ae097d9cb4ed4e56 ("Introduce arena library and runtime)
> 
> [...]

Here is the summary with links:
  - [bpf-next] selftests/bpf: Rename libarena malloc/free methods
    https://git.kernel.org/bpf/bpf-next/c/9f5b3ffc3f1d

You are awesome, thank you!
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