From: Alexander Holler <holler@ahsoftware.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: Richard Weinberger <richard.weinberger@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Tejun Heo <htejun@gmail.com>,
Louis Langholtz <lou_langholtz@me.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Trivial patch monkey <trivial@kernel.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Gleixner <tglx@linutronix.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] debug: Deprecate BUG_ON() use in new code, introduce CRASH_ON()
Date: Mon, 08 Jun 2015 11:22:03 +0200 [thread overview]
Message-ID: <55755EBB.7020105@ahsoftware.de> (raw)
In-Reply-To: <20150608091132.GA19566@gmail.com>
Am 08.06.2015 um 11:11 schrieb Ingo Molnar:
>
> * Ingo Molnar <mingo@kernel.org> wrote:
>
>> Firstly, the changelog of the patch that Greg rejected told nothing about all
>> that thinking, so at minimum it's a deficient changelog.
>>
>> Secondly and more importantly, instead of doing a BUG_ON() you could have done:
>>
>> if (WARN_ON_ONCE(port->itty))
>> return;
>>
>> This would probably have prevented the tty related memory corruption just as
>> much, at the cost of a (small and infrequent) memory leak.
>>
>> I.e. instead of crashing the machine, you need to try to find the least
>> destructive approach if a bug is detected.
>
> Also note that BUG_ON() will make data corruption _worse_ statistically. Why?
> Because most data corruptions are unlikely to be perfectly detected by a BUG_ON(),
> and the BUG_ON() delays the finding of the underlying bug, so the bug will hit
> more people before it's fixed for good.
>
> So even in the cases where you could argue that the system needs to stop, because
> we have evidence of data corruption, it's statistically the better approach to
> continue and get kernel log info back to developers.
Risking more, maybe even worse problems like corrupting file systems or
similiar in order to have a slightly chance of save log info?
Sorry, that isn't something I would propose.
Anyway, CRASH_ON didn't exist, so I only had the choice between BUG_ON
and WARN_ON, and for the latter you need a proper exit path which isn't
always easy to find. So I appreciate CRASH_ON, thanks.
Alexander Holler
next prev parent reply other threads:[~2015-06-08 9:22 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <http://marc.info/?l=linux-kernel&m=143351431301630>
2015-06-07 23:54 ` [PATCH] kernel/params.c: make use of unused but set variable Louis Langholtz
2015-06-08 0:00 ` Tejun Heo
2015-06-08 0:17 ` Linus Torvalds
2015-06-08 0:58 ` Tejun Heo
2015-06-08 5:24 ` [PATCH v2] " Louis Langholtz
2015-06-10 17:05 ` [PATCH] " Louis Langholtz
2015-06-11 1:54 ` Tejun Heo
2015-06-12 3:17 ` Louis Langholtz
2015-06-08 5:44 ` [PATCH] checkpatch: Warn on BUG and BUG_ON uses Joe Perches
2015-06-08 5:46 ` [PATCH] kernel/params.c: make use of unused but set variable Louis Langholtz
2015-06-08 7:12 ` [PATCH] debug: Deprecate BUG_ON() use in new code, introduce CRASH_ON() Ingo Molnar
2015-06-08 7:40 ` Alexander Holler
2015-06-08 8:08 ` Richard Weinberger
2015-06-08 8:42 ` Alexander Holler
2015-06-08 9:05 ` Ingo Molnar
2015-06-08 9:11 ` Ingo Molnar
2015-06-08 9:22 ` Alexander Holler [this message]
2015-06-08 11:29 ` Ingo Molnar
2015-06-08 9:16 ` Alexander Holler
2015-06-08 11:27 ` Ingo Molnar
2015-06-08 18:07 ` Alexander Holler
2015-06-08 19:35 ` Ingo Molnar
2015-06-09 1:07 ` Alexander Holler
2015-06-08 8:09 ` Ingo Molnar
2015-06-12 1:27 ` [PATCH] kernel/params.c: make use of unused but set variable Rusty Russell
2015-06-12 1:48 ` Tejun Heo
2015-06-14 19:49 ` Rusty Russell
2015-06-16 19:54 ` Tejun Heo
2015-06-08 14:26 [PATCH] debug: Deprecate BUG_ON() use in new code, introduce CRASH_ON() Alexey Dobriyan
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