* [PATCH v1] tools build: Fix timerfd feature detection with clang
@ 2026-09-10 21:39 Ian Rogers
2026-09-10 21:41 ` sashiko-bot
2026-09-12 20:15 ` Arnaldo Carvalho de Melo
0 siblings, 2 replies; 3+ messages in thread
From: Ian Rogers @ 2026-09-10 21:39 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Jiri Olsa, Ian Rogers, Adrian Hunter, James Clark,
linux-perf-users, linux-kernel, Nathan Chancellor,
Nick Desaulniers, Bill Wendling, Justin Stitt, llvm
Clang's uninitialized-const-pointer warning causes a feature test to
fail when building perf with clang. This disables support for 'perf
kvm stat live'. Add default initialization to new_value as a
workaround.
test-timerfd.c:15:30: error: variable 'new_value' is uninitialized when passed
as a const pointer argument here
[-Werror,-Wuninitialized-const-pointer]
15 | if (timerfd_settime(fd, 0, &new_value, NULL) != 0)
| ^~~~~~~~~
1 error generated.
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/build/feature/test-timerfd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/build/feature/test-timerfd.c b/tools/build/feature/test-timerfd.c
index 9c72c697a9df..f88e8cc63ef3 100644
--- a/tools/build/feature/test-timerfd.c
+++ b/tools/build/feature/test-timerfd.c
@@ -6,7 +6,7 @@
int main(void)
{
- struct itimerspec new_value;
+ struct itimerspec new_value = {};
int fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
if (fd < 0)
--
2.55.0.1007.g17ff1f9808-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v1] tools build: Fix timerfd feature detection with clang
2026-09-10 21:39 [PATCH v1] tools build: Fix timerfd feature detection with clang Ian Rogers
@ 2026-09-10 21:41 ` sashiko-bot
2026-09-12 20:15 ` Arnaldo Carvalho de Melo
1 sibling, 0 replies; 3+ messages in thread
From: sashiko-bot @ 2026-09-10 21:41 UTC (permalink / raw)
To: Ian Rogers; +Cc: linux-perf-users
> Clang's uninitialized-const-pointer warning causes a feature test to
> fail when building perf with clang. This disables support for 'perf
> kvm stat live'. Add default initialization to new_value as a
> workaround.
>
> test-timerfd.c:15:30: error: variable 'new_value' is uninitialized when passed
> as a const pointer argument here
> [-Werror,-Wuninitialized-const-pointer]
> 15 | if (timerfd_settime(fd, 0, &new_value, NULL) != 0)
> | ^~~~~~~~~
> 1 error generated.
>
> Signed-off-by: Ian Rogers <irogers@google.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260910213907.3206529-1-irogers@google.com?part=1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v1] tools build: Fix timerfd feature detection with clang
2026-09-10 21:39 [PATCH v1] tools build: Fix timerfd feature detection with clang Ian Rogers
2026-09-10 21:41 ` sashiko-bot
@ 2026-09-12 20:15 ` Arnaldo Carvalho de Melo
1 sibling, 0 replies; 3+ messages in thread
From: Arnaldo Carvalho de Melo @ 2026-09-12 20:15 UTC (permalink / raw)
To: Ian Rogers
Cc: Peter Zijlstra, Ingo Molnar, Namhyung Kim, Jiri Olsa,
Adrian Hunter, James Clark, linux-perf-users, linux-kernel,
Nathan Chancellor, Nick Desaulniers, Bill Wendling, Justin Stitt,
llvm
On Thu, Sep 10, 2026 at 02:39:07PM -0700, Ian Rogers wrote:
> Clang's uninitialized-const-pointer warning causes a feature test to
> fail when building perf with clang. This disables support for 'perf
> kvm stat live'. Add default initialization to new_value as a
> workaround.
>
> test-timerfd.c:15:30: error: variable 'new_value' is uninitialized when passed
> as a const pointer argument here
> [-Werror,-Wuninitialized-const-pointer]
> 15 | if (timerfd_settime(fd, 0, &new_value, NULL) != 0)
> | ^~~~~~~~~
> 1 error generated.
>
> Signed-off-by: Ian Rogers <irogers@google.com>
Thanks, applied to perf-tools-next, for v7.4.
- Arnaldo
> ---
> tools/build/feature/test-timerfd.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/build/feature/test-timerfd.c b/tools/build/feature/test-timerfd.c
> index 9c72c697a9df..f88e8cc63ef3 100644
> --- a/tools/build/feature/test-timerfd.c
> +++ b/tools/build/feature/test-timerfd.c
> @@ -6,7 +6,7 @@
>
> int main(void)
> {
> - struct itimerspec new_value;
> + struct itimerspec new_value = {};
>
> int fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
> if (fd < 0)
> --
> 2.55.0.1007.g17ff1f9808-goog
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-09-10 21:39 [PATCH v1] tools build: Fix timerfd feature detection with clang Ian Rogers
2026-09-10 21:41 ` sashiko-bot
2026-09-12 20:15 ` Arnaldo Carvalho de Melo
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