From: Kees Cook <keescook@chromium.org>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 00/19] Enable -Wshadow=local for kernel/sched
Date: Wed, 2 Mar 2022 10:32:23 -0800 [thread overview]
Message-ID: <202203021030.EEEF58C2@keescook> (raw)
In-Reply-To: <20220302043451.2441320-1-willy@infradead.org>
On Wed, Mar 02, 2022 at 04:34:32AM +0000, Matthew Wilcox (Oracle) wrote:
> I thought I'd choose one of the more core parts of the kernel to
> demonstrate the value of -Wshadow. It found two places where there are
> shadowed variables that are at least confusing. For all I know they're
> buggy and my resolution of these warnings is wrong.
>
> The first 12 patches just untangle the unclean uses of __ret in wait.h
> & friends. Then 4 patches to fix problems in headers that are noticed
> by kernel/sched. Two patches fix the two places in kernel/sched/
> with shadowed variables and the final patch adds -Wshadow=local to
> the Makefile.
You are my hero. I was pulling my hair out trying to figure out how
to deal with this a few months ago, and the use of UNIQUE_ID was the
key. Yay!
> I'm quite certain this patch series isn't going in as-is. But maybe
> it'll inspire some patches that can go in.
I think it's pretty darn close. One thing that can be done to test the
results for the first 12 patches is to do a binary comparison -- these
changes _should_ have no impact on the final machine code. (It'll
totally change the debug sections, etc, but the machine code should be
the same.)
--
Kees Cook
next prev parent reply other threads:[~2022-03-02 18:32 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-02 4:34 [PATCH 00/19] Enable -Wshadow=local for kernel/sched Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 01/19] wait: Parameterize the return variable to ___wait_event() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 02/19] swait: Parameterize the return variable to __swait_event_timeout() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 03/19] swait: Parameterize the return variable to __swait_event_interruptible_timeout() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 04/19] swait: Parameterize the return variable to __swait_event_idle_timeout() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 05/19] wait: Parameterize the return variable to __wait_event_timeout() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 06/19] wait: Parameterize the return variable to __wait_event_freezable_timeout() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 07/19] wait: Parameterize the return variable to __wait_event_interruptible_timeout() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 08/19] wait: Parameterize the return variable to __wait_event_idle_timeout() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 09/19] wait: Parameterize the return variable to __wait_event_idle_exclusive_timeout() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 10/19] wait: Parameterize the return variable to __wait_event_killable_timeout() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 11/19] wait: Parameterize the return variable to __wait_event_lock_irq_timeout() Matthew Wilcox (Oracle)
2022-03-02 4:34 ` [PATCH 12/19] wait_bit: Parameterize the return variable to __wait_var_event_timeout() Matthew Wilcox (Oracle)
2022-03-02 18:32 ` Kees Cook [this message]
2022-03-02 18:43 ` [PATCH 00/19] Enable -Wshadow=local for kernel/sched Matthew Wilcox
2022-03-02 19:18 ` Peter Zijlstra
2024-04-16 21:15 ` Kees Cook
2024-04-17 0:29 ` Linus Torvalds
2024-04-17 0:50 ` Linus Torvalds
2024-04-17 0:52 ` Matthew Wilcox
2024-04-17 11:23 ` Ingo Molnar
2024-04-19 22:06 ` Kees Cook
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