[PATCH bpf-next] selftests/bpf: fix selection of static vs. dynamic LLVM

[PATCH bpf-next] selftests/bpf: fix selection of static vs. dynamic LLVM

[Anton Protopopov]

The Makefile uses the exit code of the `llvm-config --link-static --libs`
command to choose between statically-linked and dynamically-linked LLVMs.
The stdout and stderr of that command are redirected to /dev/null.
To redirect the output the "&>" construction is used, which might not be
supported by /bin/sh, which is executed by make for $(shell ...) commands.
On such systems the test will fail even if static LLVM is actually
supported. Replace "&>" by ">/dev/null 2>&1" to fix this.

Fixes: 2a9d30fac818 ("selftests/bpf: Support dynamically linking LLVM if static is not available")
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
---
 tools/testing/selftests/bpf/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 739305064839..ca41d47d4ba6 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -180,7 +180,7 @@ ifeq ($(feature-llvm),1)
   # both llvm-config and lib.mk add -D_GNU_SOURCE, which ends up as conflict
   LLVM_CFLAGS  += $(filter-out -D_GNU_SOURCE,$(shell $(LLVM_CONFIG) --cflags))
   # Prefer linking statically if it's available, otherwise fallback to shared
-  ifeq ($(shell $(LLVM_CONFIG) --link-static --libs &> /dev/null && echo static),static)
+  ifeq ($(shell $(LLVM_CONFIG) --link-static --libs >/dev/null 2>&1 && echo static),static)
     LLVM_LDLIBS  += $(shell $(LLVM_CONFIG) --link-static --libs $(LLVM_CONFIG_LIB_COMPONENTS))
     LLVM_LDLIBS  += $(shell $(LLVM_CONFIG) --link-static --system-libs $(LLVM_CONFIG_LIB_COMPONENTS))
     LLVM_LDLIBS  += -lstdc++
-- 
2.34.1

Re: [PATCH bpf-next] selftests/bpf: fix selection of static vs. dynamic LLVM

[Daniel Xu]

On Mon, Mar 10, 2025 at 02:51:12PM +0000, Anton Protopopov wrote:
> The Makefile uses the exit code of the `llvm-config --link-static --libs`
> command to choose between statically-linked and dynamically-linked LLVMs.
> The stdout and stderr of that command are redirected to /dev/null.
> To redirect the output the "&>" construction is used, which might not be
> supported by /bin/sh, which is executed by make for $(shell ...) commands.
> On such systems the test will fail even if static LLVM is actually
> supported. Replace "&>" by ">/dev/null 2>&1" to fix this.
> 
> Fixes: 2a9d30fac818 ("selftests/bpf: Support dynamically linking LLVM if static is not available")
> Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
> ---
>  tools/testing/selftests/bpf/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index 739305064839..ca41d47d4ba6 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -180,7 +180,7 @@ ifeq ($(feature-llvm),1)
>    # both llvm-config and lib.mk add -D_GNU_SOURCE, which ends up as conflict
>    LLVM_CFLAGS  += $(filter-out -D_GNU_SOURCE,$(shell $(LLVM_CONFIG) --cflags))
>    # Prefer linking statically if it's available, otherwise fallback to shared
> -  ifeq ($(shell $(LLVM_CONFIG) --link-static --libs &> /dev/null && echo static),static)
> +  ifeq ($(shell $(LLVM_CONFIG) --link-static --libs >/dev/null 2>&1 && echo static),static)
>      LLVM_LDLIBS  += $(shell $(LLVM_CONFIG) --link-static --libs $(LLVM_CONFIG_LIB_COMPONENTS))
>      LLVM_LDLIBS  += $(shell $(LLVM_CONFIG) --link-static --system-libs $(LLVM_CONFIG_LIB_COMPONENTS))
>      LLVM_LDLIBS  += -lstdc++
> -- 
> 2.34.1
> 

Acked-by: Daniel Xu <dxu@dxuuu.xyz>

Re: [PATCH bpf-next] selftests/bpf: fix selection of static vs. dynamic LLVM

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Mon, 10 Mar 2025 14:51:12 +0000 you wrote:
> The Makefile uses the exit code of the `llvm-config --link-static --libs`
> command to choose between statically-linked and dynamically-linked LLVMs.
> The stdout and stderr of that command are redirected to /dev/null.
> To redirect the output the "&>" construction is used, which might not be
> supported by /bin/sh, which is executed by make for $(shell ...) commands.
> On such systems the test will fail even if static LLVM is actually
> supported. Replace "&>" by ">/dev/null 2>&1" to fix this.
> 
> [...]

Here is the summary with links:
  - [bpf-next] selftests/bpf: fix selection of static vs. dynamic LLVM
    https://git.kernel.org/bpf/bpf-next/c/74f36a97e5e5

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html