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 both /usr/include/sys/prctl.h and /linux/tools/include/uapi/linux/prctl.h
provide struct prctl_mm_map but their include guard must be different.
/usr/include/sys/prctl.h provided by glibc contains the
prctl() declaration. It includes also 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 don't include linux/prctl.h explicitely and add some new defines
needed if they aren't available.
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Namhyung Kim <namhyung@kernel.org>
Closes: https://lore.kernel.org/r/20250611092542.F4ooE2FL@linutronix.de
Link: https://www.openwall.com/lists/musl/2025/06/12/11
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The prctl.h ABI header was slightly updated during the development of
the interface. In particular the "immutable" parameter became a bit in
the option argument.
Synchronize prctl.h ABI header again and make use of the definition in
the testsuite and "perf bench futex".
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20250517151455.1065363-5-bigeasy@linutronix.de
Add the -b/ --buckets argument to specify the number of hash buckets for
the private futex hash. This is directly passed to
prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_SET_SLOTS, buckets, immutable)
and must return without an error if specified. The `immutable' is 0 by
default and can be set to 1 via the -I/ --immutable argument.
The size of the private hash is verified with PR_FUTEX_HASH_GET_SLOTS.
If PR_FUTEX_HASH_GET_SLOTS failed then it is assumed that an older
kernel was used without the support and that the global hash is used.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250416162921.513656-20-bigeasy@linutronix.de
