From: Peter Zijlstra <peterz@infradead.org>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Jason Baron <jbaron@akamai.com>, Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Ard Biesheuvel <ardb@kernel.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Frederic Weisbecker <frederic@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] static_call: fix function type mismatch
Date: Tue, 23 Mar 2021 08:35:59 +0100 [thread overview]
Message-ID: <YFmaXxwcAb9bPchv@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAK8P3a2sz4emewH_HA+nsf0e5tP6qtAxhBOFucmzW4OPDJASdQ@mail.gmail.com>
On Mon, Mar 22, 2021 at 10:18:17PM +0100, Arnd Bergmann wrote:
> > Steve is correct. Also, why is that warning correct? On x86 we return in
> > RAX, and using int will simply not inspect the upper 32 bits there.
>
> I think the code works correctly on all architectures we support because
> both 'int' and 'long' are returned in a register with any unused bits cleared.
> It is however undefined behavior in C because 'int' and 'long' are not
> compatible types, and the calling conventions don't have to allow this.
Then please kill the warning, it's bullshit.
> > And I'm fairly sure I had a pointer user somewhere recently.
>
> I've only tested my series with 5.12-rc so far, but don't get any other
> such warnings. Maybe it's in linux-next?
No, it's in Linus' tree, see commit:
c8e2fe13d1d1 ("x86/perf: Use RET0 as default for guest_get_msrs to handle "no PMU" case")
prev parent reply other threads:[~2021-03-23 7:38 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 17:06 [PATCH] static_call: fix function type mismatch Arnd Bergmann
2021-03-22 19:32 ` Steven Rostedt
2021-03-22 20:47 ` Peter Zijlstra
2021-03-22 21:18 ` Arnd Bergmann
2021-03-22 21:29 ` Steven Rostedt
2021-03-23 7:47 ` Peter Zijlstra
2021-03-24 12:46 ` Rasmus Villemoes
2021-03-24 16:01 ` Sami Tolvanen
2021-03-24 16:45 ` Rasmus Villemoes
2021-03-24 17:33 ` Peter Zijlstra
2021-03-24 19:16 ` Peter Zijlstra
2021-03-24 21:51 ` Rasmus Villemoes
2021-03-24 22:34 ` Sami Tolvanen
2021-03-24 22:53 ` Rasmus Villemoes
2021-03-24 23:40 ` Sami Tolvanen
2021-03-25 0:42 ` Rasmus Villemoes
2021-03-25 7:42 ` Peter Zijlstra
2021-03-25 7:45 ` Ard Biesheuvel
2021-03-25 8:27 ` Rasmus Villemoes
2021-03-23 7:35 ` Peter Zijlstra [this message]
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