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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E. McKenney" <paulmck@us.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [GIT PULL] locking fixes
Date: Tue, 28 Feb 2017 10:37:15 -0800	[thread overview]
Message-ID: <CA+55aFzbYUTZ=oqZ2YgDjY0C2_n6ODhTfqj6V+m5xWmDxsuB0w@mail.gmail.com> (raw)
In-Reply-To: <20170228075747.GA10419@gmail.com>

On Mon, Feb 27, 2017 at 11:57 PM, Ingo Molnar <mingo@kernel.org> wrote:
>
> Note that the uninlining allowed us to enable the underflow/overflow warnings
> unconditionally and remove the debug Kconfig switch: this might trigger new
> warnings in buggy code and turn crashes/use-after-free bugs into less harmful
> memory leaks.

I'm ok with this, but that WARN() really needs to be a WARN_ON_ONCE().

Because once an underflow (or overflow) is happening, it tends to
_keep_ happening. And you may just have essentially DoS'ed the machine
that is now spending all its time writing those logs to disk.

Yes, yes, quiet independently of this we should limit WARN printouts
(and do the reverse: turn a "once" to mean "once in a blue moon"
rather than actually just once), but particularly for this kind of
"never happens" thing, it really is better to just warn once.

                   Linus

  reply	other threads:[~2017-03-01  6:23 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-28  7:57 [GIT PULL] locking fixes Ingo Molnar
2017-02-28 18:37 ` Linus Torvalds [this message]
2017-03-01  8:30   ` [PATCH] locking/refcounts: Change WARN() to WARN_ONCE() Ingo Molnar
2017-03-01  8:33   ` [tip:locking/urgent] " tip-bot for Ingo Molnar
2017-05-03 23:21 ` [GIT PULL] locking fixes Linus Torvalds
2017-05-04  5:40   ` Peter Zijlstra
     [not found]     ` <CA+55aFymvtCAYHdz__3Lj=YqmORB7_A-NXrw=+h+60znJVsDTw@mail.gmail.com>
2017-05-04 22:44       ` Greg Kroah-Hartman
2017-05-04 22:51         ` refcount: change EXPORT_SYMBOL markings Greg Kroah-Hartman
  -- strict thread matches above, loose matches on Subject: below --
2023-09-22 10:12 [GIT PULL] locking fixes Ingo Molnar
2023-09-22 20:19 ` pr-tracker-bot
2021-07-11 13:22 Ingo Molnar
2021-07-11 18:22 ` pr-tracker-bot
2021-04-11 12:14 Ingo Molnar
2021-04-11 18:56 ` pr-tracker-bot
2021-03-21 10:53 Ingo Molnar
2021-03-21 18:45 ` pr-tracker-bot
2020-12-27  9:50 Ingo Molnar
2020-12-27 17:27 ` pr-tracker-bot
2020-08-15 11:13 Ingo Molnar
2020-08-16  1:55 ` pr-tracker-bot
2020-01-18 17:53 Ingo Molnar
2020-01-18 21:05 ` pr-tracker-bot
2019-12-17 11:27 Ingo Molnar
2019-12-17 19:20 ` pr-tracker-bot
2019-04-20  7:30 Ingo Molnar
2019-04-20 16:51 ` Linus Torvalds
2019-04-21 18:23   ` Ingo Molnar
2019-04-20 19:25 ` pr-tracker-bot
2019-02-10  8:53 Ingo Molnar
2019-02-10 18:30 ` pr-tracker-bot
2018-10-05  9:36 Ingo Molnar
2018-10-05 23:06 ` Greg Kroah-Hartman
2018-09-15 12:56 Ingo Molnar
2018-07-30 17:49 Ingo Molnar
2018-03-25  8:49 Ingo Molnar
2018-02-15  0:50 Ingo Molnar
2018-01-17 15:24 Ingo Molnar
2018-01-22  9:43 ` Geert Uytterhoeven
2018-01-22 10:39   ` Peter Zijlstra
2018-01-12 13:45 Ingo Molnar
2017-12-15 15:55 Ingo Molnar
2017-10-14 16:01 Ingo Molnar
2017-03-07 20:27 Ingo Molnar
2016-12-07 18:42 Ingo Molnar
2016-10-18 10:55 Ingo Molnar
2016-08-18 20:34 Ingo Molnar
2016-08-12 19:32 Ingo Molnar
2016-06-10 12:45 Ingo Molnar
2016-04-28 17:52 Ingo Molnar
2016-04-23 11:22 Ingo Molnar
2016-03-24  7:47 Ingo Molnar
2015-09-17  7:57 Ingo Molnar
2015-04-18 15:15 Ingo Molnar
2015-02-20 13:37 Ingo Molnar
2015-02-21  0:03 ` Linus Torvalds
2015-02-21  1:51   ` Linus Torvalds
2015-02-23  8:35     ` Christian Borntraeger
2015-02-21  5:07   ` Ingo Molnar
2015-02-21  5:16     ` Ingo Molnar
2015-02-21  5:28       ` Ingo Molnar
2015-01-11  8:39 Ingo Molnar
2014-10-31 11:06 Ingo Molnar
2014-04-16 11:39 Ingo Molnar
2014-01-15 18:15 Ingo Molnar
2009-12-10 19:45 Ingo Molnar

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