From: Frederic Weisbecker <fweisbec@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2] atomic: Fix bugs in 'fetch_or()' and rename it to 'xchg_or()'
Date: Thu, 17 Mar 2016 01:54:33 +0100 [thread overview]
Message-ID: <20160317005431.GA29781@lerouge> (raw)
In-Reply-To: <20160316081444.GB31133@gmail.com>
On Wed, Mar 16, 2016 at 09:14:44AM +0100, Ingo Molnar wrote:
> Yeah, so in the perf tooling build we do have -Wshadow to catch such mishaps,
> but not in the main kernel build.
>
> ... and yes, if I add it via the patch below the bug gets warned about:
>
> include/linux/atomic.h:561:15: note: shadowed declaration is here
> typeof(ptr) __ptr = (ptr); \
> ^
> kernel/sched/core.c:332:11: note: in expansion of macro ‘xchg_or’
> return !(xchg_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLA
>
> ... but I also get a ton of other warnings, just when building a single
> kernel/sched/core.o file:
>
> ./arch/x86/include/asm/bitops.h:396:28: warning: declaration of ‘ffs’ shadows a built-in function [-Wshadow]
> ./arch/x86/include/asm/bitops.h:396:28: warning: declaration of ‘ffs’ shadows a built-in function [-Wshadow]
> include/linux/jiffies.h:422:60: warning: declaration of ‘jiffies’ shadows a global declaration [-Wshadow]
> ./arch/x86/include/asm/io_apic.h:187:54: warning: declaration of ‘apic’ shadows a global declaration [-Wshadow]
> ./arch/x86/include/asm/bitops.h:396:28: warning: declaration of ‘ffs’ shadows a built-in function [-Wshadow]
> include/linux/jiffies.h:422:60: warning: declaration of ‘jiffies’ shadows a global declaration [-Wshadow]
> ./arch/x86/include/asm/io_apic.h:187:54: warning: declaration of ‘apic’ shadows a global declaration [-Wshadow]
> include/linux/kernel.h:750:12: warning: declaration of ‘_min1’ shadows a previous local [-Wshadow]
> include/linux/kernel.h:750:12: warning: declaration of ‘_min1’ shadows a previous local [-Wshadow]
> include/linux/kernel.h:751:12: warning: declaration of ‘_min2’ shadows a previous local [-Wshadow]
> kernel/sched/sched.h:308:43: warning: declaration of ‘down’ shadows a global declaration [-Wshadow]
> kernel/sched/sched.h:308:60: warning: declaration of ‘up’ shadows a global declaration [-Wshadow]
> kernel/sched/auto_group.h:44:55: warning: declaration of ‘init_task’ shadows a global declaration [-Wshadow]
> kernel/sched/core.c:635:20: warning: declaration of ‘down’ shadows a global declaration [-Wshadow]
> kernel/sched/core.c:635:37: warning: declaration of ‘up’ shadows a global declaration [-Wshadow]
Heh, what else can we expect from global functions named up() and down() in a millions-lines C project :-)
>
> and yes, I'd say most of these are signatures of sloppy macros and sloppy variable
> names - but it would be a ton of work to eliminate these warnings.
Yeah that's what I was afraid of.
Thanks for trying it though!
next prev parent reply other threads:[~2016-03-17 0:54 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-14 12:32 [GIT PULL] NOHZ updates for v4.6 Ingo Molnar
2016-03-15 2:44 ` Linus Torvalds
2016-03-15 8:42 ` Peter Zijlstra
2016-03-15 9:49 ` Ingo Molnar
2016-03-15 9:32 ` [PATCH] atomic: Fix bugs in 'fetch_or()' and rename it to 'xchg_or()' Ingo Molnar
2016-03-15 10:50 ` Peter Zijlstra
2016-03-15 12:08 ` Ingo Molnar
2016-03-15 12:42 ` Peter Zijlstra
2016-03-15 11:06 ` Peter Zijlstra
2016-03-15 11:59 ` Peter Zijlstra
2016-03-15 12:01 ` Ingo Molnar
2016-03-15 12:32 ` Ingo Molnar
2016-03-15 12:37 ` Ingo Molnar
2016-03-15 13:17 ` Peter Zijlstra
2016-03-15 12:21 ` [PATCH v2] " Ingo Molnar
2016-03-15 13:26 ` Peter Zijlstra
2016-03-16 8:04 ` Ingo Molnar
2016-03-16 8:29 ` Peter Zijlstra
2016-03-15 17:08 ` Frederic Weisbecker
2016-03-16 8:14 ` Ingo Molnar
2016-03-17 0:54 ` Frederic Weisbecker [this message]
2016-03-15 16:18 ` [PATCH] " Linus Torvalds
2016-03-15 9:53 ` [PATCH] nohz: Change tick_dep_mask from 'unsigned long' to 'unsigned int' Ingo Molnar
2016-03-15 12:15 ` Ingo Molnar
2016-03-15 16:30 ` Linus Torvalds
2016-03-15 17:28 ` Frederic Weisbecker
2016-03-15 17:36 ` Linus Torvalds
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