From: "H. Peter Anvin" <hpa@zytor.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: linux-arch@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Chen Gang <gang.chen@asianux.com>,
linux-kernel@vger.kernel.org,
Geert Uytterhoeven <geert@linux-m68k.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH, re-send] Always trap on BUG()
Date: Mon, 15 Jul 2013 15:35:16 -0700 [thread overview]
Message-ID: <51E47924.9030005@zytor.com> (raw)
In-Reply-To: <20130715222755.GY24642@n2100.arm.linux.org.uk>
On 07/15/2013 03:27 PM, Russell King - ARM Linux wrote:
> On Mon, Jul 15, 2013 at 03:16:12PM -0700, Andrew Morton wrote:
>> I've been thinking for a while that CONFIG_BUG=n is a pretty dumb thing
>> to do, and that maintaining it (and trying to fix the warnings it
>> produces) aren't worth the effort and that we should remove the whole
>> thing. Perhaps your patch changes that calculus, dunno. Please discuss.
>
> This isn't about introducing "CONFIG_BUG=n" - this is about making a
> kernel with CONFIG_BUG=n build without producing tonnes and tonnes of
> warnings, as it does today. It makes building randconfig pretty
> useless to find what could be more important warnings.
>
Well, there are three alternatives here, right:
1. We can use unreachable(), which means that the compiler can assume it
never happens.
2. We can trap without metadata.
3. We can trap with metadata (current CONFIG_BUG=y).
I am *guessing* this does 2, but it isn't clear.
-hpa
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>,
linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Chen Gang <gang.chen@asianux.com>,
Ingo Molnar <mingo@kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Geert Uytterhoeven <geert@linux-m68k.org>
Subject: Re: [PATCH, re-send] Always trap on BUG()
Date: Mon, 15 Jul 2013 15:35:16 -0700 [thread overview]
Message-ID: <51E47924.9030005@zytor.com> (raw)
Message-ID: <20130715223516.8US-m4T3UEmHt2Gbb1M5Ipoj09KQe_w1JGr5vVUlvuc@z> (raw)
In-Reply-To: <20130715222755.GY24642@n2100.arm.linux.org.uk>
On 07/15/2013 03:27 PM, Russell King - ARM Linux wrote:
> On Mon, Jul 15, 2013 at 03:16:12PM -0700, Andrew Morton wrote:
>> I've been thinking for a while that CONFIG_BUG=n is a pretty dumb thing
>> to do, and that maintaining it (and trying to fix the warnings it
>> produces) aren't worth the effort and that we should remove the whole
>> thing. Perhaps your patch changes that calculus, dunno. Please discuss.
>
> This isn't about introducing "CONFIG_BUG=n" - this is about making a
> kernel with CONFIG_BUG=n build without producing tonnes and tonnes of
> warnings, as it does today. It makes building randconfig pretty
> useless to find what could be more important warnings.
>
Well, there are three alternatives here, right:
1. We can use unreachable(), which means that the compiler can assume it
never happens.
2. We can trap without metadata.
3. We can trap with metadata (current CONFIG_BUG=y).
I am *guessing* this does 2, but it isn't clear.
-hpa
WARNING: multiple messages have this Message-ID (diff)
From: hpa@zytor.com (H. Peter Anvin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH, re-send] Always trap on BUG()
Date: Mon, 15 Jul 2013 15:35:16 -0700 [thread overview]
Message-ID: <51E47924.9030005@zytor.com> (raw)
In-Reply-To: <20130715222755.GY24642@n2100.arm.linux.org.uk>
On 07/15/2013 03:27 PM, Russell King - ARM Linux wrote:
> On Mon, Jul 15, 2013 at 03:16:12PM -0700, Andrew Morton wrote:
>> I've been thinking for a while that CONFIG_BUG=n is a pretty dumb thing
>> to do, and that maintaining it (and trying to fix the warnings it
>> produces) aren't worth the effort and that we should remove the whole
>> thing. Perhaps your patch changes that calculus, dunno. Please discuss.
>
> This isn't about introducing "CONFIG_BUG=n" - this is about making a
> kernel with CONFIG_BUG=n build without producing tonnes and tonnes of
> warnings, as it does today. It makes building randconfig pretty
> useless to find what could be more important warnings.
>
Well, there are three alternatives here, right:
1. We can use unreachable(), which means that the compiler can assume it
never happens.
2. We can trap without metadata.
3. We can trap with metadata (current CONFIG_BUG=y).
I am *guessing* this does 2, but it isn't clear.
-hpa
next prev parent reply other threads:[~2013-07-15 22:35 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-05 15:38 [PATCH, re-send] Always trap on BUG() Arnd Bergmann
2013-07-05 15:38 ` Arnd Bergmann
2013-07-12 10:15 ` Ingo Molnar
2013-07-12 10:15 ` Ingo Molnar
2013-07-15 22:16 ` Andrew Morton
2013-07-15 22:16 ` Andrew Morton
2013-07-15 22:27 ` Russell King - ARM Linux
2013-07-15 22:27 ` Russell King - ARM Linux
2013-07-15 22:35 ` H. Peter Anvin [this message]
2013-07-15 22:35 ` H. Peter Anvin
2013-07-15 22:35 ` H. Peter Anvin
2013-07-15 22:47 ` Russell King - ARM Linux
2013-07-15 22:47 ` Russell King - ARM Linux
2013-07-23 9:36 ` Ingo Molnar
2013-07-23 9:36 ` Ingo Molnar
2013-07-23 9:54 ` H. Peter Anvin
2013-07-23 9:54 ` H. Peter Anvin
2013-07-23 9:54 ` H. Peter Anvin
2013-07-24 0:00 ` Chen Gang
2013-07-24 0:00 ` Chen Gang
2013-07-25 22:05 ` Ingo Molnar
2013-07-25 22:05 ` Ingo Molnar
2013-07-26 1:05 ` Chen Gang
2013-07-26 1:05 ` Chen Gang
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