From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>,
linux-sh@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Ben Segall <bsegall@google.com>, Guo Ren <guoren@kernel.org>,
Pavel Machek <pavel@ucw.cz>,
Vincent Guittot <vincent.guittot@linaro.org>,
Paul Burton <paulburton@kernel.org>,
Dmitry Safonov <dima@arista.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Mel Gorman <mgorman@suse.de>, Jiri Slaby <jslaby@suse.com>,
Matt Turner <mattst88@gmail.com>,
uclinux-h8-devel@lists.sourceforge.jp,
Len Brown <len.brown@intel.com>,
linux-pm@vger.kernel.org,
Heiko Carstens <heiko.carstens@de.ibm.com>,
linux-um@lists.infradead.org,
Thomas Gleixner <tglx@linutronix.de>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Richard Henderson <rth@twiddle.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
linux-kerne
Subject: Re: [PATCH 00/50] Add log level to show_stack()
Date: Wed, 6 Nov 2019 23:25:13 +0000 [thread overview]
Message-ID: <20191106232512.GU25745@shell.armlinux.org.uk> (raw)
In-Reply-To: <20191106203440.GH3079@worktop.programming.kicks-ass.net>
On Wed, Nov 06, 2019 at 09:34:40PM +0100, Peter Zijlstra wrote:
> I suppose I'm surprised there are backtraces that are not important.
> Either badness happened and it needs printing, or the user asked for it
> and it needs printing.
Or utterly meaningless.
> Perhaps we should be removing backtraces if they're not important
> instead of allowing to print them as lower loglevels?
Definitely! WARN_ON() is well overused - and as is typical, used
without much thought. Bound to happen after Linus got shirty about
BUG_ON() being over used. Everyone just grabbed the next nearest thing
to assert().
As a kind of example, I've recently come across one WARN_ON() in a
driver subsystem (that shall remain nameless at the moment) which very
likely has multiple different devices on a platform. The WARN_ON()
triggers as a result of a problem with the hardware, but because it's a
WARN_ON(), you've no idea which device has a problem. The backtrace is
mostly meaningless. So you know that a problem has occurred, but the
kernel prints *useless* backtrace to let you know, and totally omits
the *useful* information.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up
next prev parent reply other threads:[~2019-11-06 23:25 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-06 3:04 [PATCH 00/50] Add log level to show_stack() Dmitry Safonov
2019-11-06 3:05 ` [PATCH 14/50] hexagon: Add show_stack_loglvl() Dmitry Safonov
2019-11-06 8:35 ` [PATCH 00/50] Add log level to show_stack() Petr Mladek
2019-11-06 16:12 ` Dmitry Safonov
2019-11-08 10:37 ` Sergey Senozhatsky
2019-11-08 13:04 ` Petr Mladek
2019-11-11 1:23 ` Sergey Senozhatsky
2019-11-11 9:12 ` Petr Mladek
2019-11-12 4:44 ` Sergey Senozhatsky
2019-11-12 4:57 ` Sergey Senozhatsky
2019-11-12 8:35 ` Petr Mladek
2019-11-12 10:12 ` Sergey Senozhatsky
2019-11-13 1:23 ` Sergey Senozhatsky
2019-11-13 2:25 ` Dmitry Safonov
2019-11-13 6:33 ` Sergey Senozhatsky
2019-11-13 8:47 ` Petr Mladek
2019-11-13 16:24 ` Steven Rostedt
2019-11-13 16:40 ` Dmitry Safonov
2019-11-15 0:50 ` Sergey Senozhatsky
2019-11-13 15:32 ` Steven Rostedt
2019-11-11 19:47 ` Dmitry Safonov
2019-11-12 2:17 ` Sergey Senozhatsky
2019-11-12 2:40 ` Dmitry Safonov
2019-11-12 4:25 ` Sergey Senozhatsky
2019-11-13 2:41 ` Dmitry Safonov
2019-11-13 2:51 ` Sergey Senozhatsky
2019-11-13 15:39 ` Steven Rostedt
2019-11-15 3:36 ` Sergey Senozhatsky
2019-11-06 9:20 ` Peter Zijlstra
2019-11-06 16:27 ` Dmitry Safonov
2019-11-06 20:34 ` Peter Zijlstra
2019-11-06 23:25 ` Russell King - ARM Linux admin [this message]
2019-11-13 15:44 ` Steven Rostedt
2019-11-08 16:28 ` Dmitry Safonov
2019-11-08 17:30 ` Russell King - ARM Linux admin
2019-11-08 21:08 ` Dmitry Safonov
2019-11-13 15:41 ` Steven Rostedt
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