Re: [BUG] perf tools: Build failure in v6.16-rc1

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2025-06-11 11:55:23 [-0300], Arnaldo Carvalho de Melo wrote:
> commit 8386dc356158fc50c55831c96b1248e01d112ebc
> Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Date:   Wed Jun 11 11:25:42 2025 +0200
> 
>     perf bench futex: Fix prctl include in musl libc
>     
>     Namhyung Kim reported:
>     
>       I've updated the perf-tools-next to v6.16-rc1 and found a build error
>       like below on alpine linux 3.18.
>     
>         In file included from bench/futex.c:6:
>         /usr/include/sys/prctl.h:88:8: error: redefinition of 'struct prctl_mm_map'
>            88 | struct prctl_mm_map {
>               |        ^~~~~~~~~~~~
>         In file included from bench/futex.c:5:
>         /linux/tools/include/uapi/linux/prctl.h:134:8: note: originally defined here
>           134 | struct prctl_mm_map {
>               |        ^~~~~~~~~~~~
>         make[4]: *** [/linux/tools/build/Makefile.build:86: /build/bench/futex.o] Error 1
>     
>       git bisect says it's the first commit introduced the failure.
>     
>     So your /usr/include/sys/prctl.h and
>     /linux/tools/include/uapi/linux/prctl.h both provide struct prctl_mm_map
>     but their include guard must be different.
>     
>     My /usr/include/sys/prctl.h is provided by glibc and contains the
>     prctl() declaration. It includes also linux/prctl.h.  The
>     tools/include/uapi/linux/prctl.h is the same as
>     /usr/include/linux/prctl.h.
>     
>     The /usr/include/sys/prctl.h on alpine linux is different. This is
>     probably coming from musl. It contains the PR_* definition and the
>     prctl() declaration.  So it clashes here because now the one struct is
>     available twice.
>     
>     The man page for prctl(2) says:
>     
>     |       #include <linux/prctl.h>  /* Definition of PR_* constants */
>     |       #include <sys/prctl.h>
>     
>     so musl doesn't follow this.
>     
>     So align with the other builds.
>     
>     Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
>     Reported-by: Namhyung Kim <namhyung@kernel.org>
>     Link: https://lore.kernel.org/r/20250611092542.F4ooE2FL@linutronix.de

s/Link/Closes/

>     [ Remove one more in tools/perf/bench/futex-hash.c and conditionally define PR_FUTEX_HASH and friends ]
>     Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> diff --git a/tools/perf/bench/futex-hash.c b/tools/perf/bench/futex-hash.c
> index fdf133c9520f73a4..d2d6d7f3ea331c84 100644
> --- a/tools/perf/bench/futex-hash.c
> +++ b/tools/perf/bench/futex-hash.c
> @@ -18,7 +18,6 @@
>  #include <stdlib.h>
>  #include <linux/compiler.h>
>  #include <linux/kernel.h>
> -#include <linux/prctl.h>
>  #include <linux/zalloc.h>
>  #include <sys/time.h>
>  #include <sys/mman.h>
> diff --git a/tools/perf/bench/futex.c b/tools/perf/bench/futex.c
> index 26382e4d8d4ce2ff..4c4fee107e5912d5 100644
> --- a/tools/perf/bench/futex.c
> +++ b/tools/perf/bench/futex.c
> @@ -2,11 +2,18 @@
>  #include <err.h>
>  #include <stdio.h>
>  #include <stdlib.h>
> -#include <linux/prctl.h>
>  #include <sys/prctl.h>
>  
This is what I had locally and was waiting for confirmation.

>  #include "futex.h"
>  
> +#ifndef PR_FUTEX_HASH
> +#define PR_FUTEX_HASH                   78
> +# define PR_FUTEX_HASH_SET_SLOTS        1
> +# define FH_FLAG_IMMUTABLE              (1ULL << 0)
> +# define PR_FUTEX_HASH_GET_SLOTS        2
> +# define PR_FUTEX_HASH_GET_IMMUTABLE    3
> +#endif // PR_FUTEX_HASH

Is this needed? Aren't these defines coming from that local copy?

>  void futex_set_nbuckets_param(struct bench_futex_parameters *params)
>  {
>  	unsigned long flags;

Sebastian