From: Dmitry Safonov <0x7f454c46@gmail•com>
To: Russell King - ARM Linux admin <linux@armlinux•org.uk>,
Dmitry Safonov <dima@arista•com>
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>,
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, 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>,
LKML <linux-kernel@vger•kernel.org>,
Ralf Baechle <ralf@linux-mips•org>,
Paul Mackerras <paulus@samba•org>,
Andrew Morton <akpm@linux-foundation•org>,
linux-ia64@vger•kernel.org,
Tetsuo Handa <penguin-kernel@i-love•sakura.ne.jp>,
James Hogan <jhogan@kernel•org>,
"James E.J. Bottomley" <James.Bottomley@hansenpartnership•com>,
Max Filippov <jcmvbkbc@gmail•com>,
Vincent Chen <deanbo422@gmail•com>,
Ingo Molnar <mingo@kernel•org>,
linux-s390@vger•kernel.org, linux-c6x-dev@linux-c6x•org,
Yoshinori Sato <ysato@users•sourceforge.jp>,
linux-hexagon@vger•kernel.org, Helge Deller <deller@gmx•de>,
"open list:TENSILICA XTENSA PORT \(xtensa\)"
<linux-xtensa@linux-xtensa•org>,
Vasily Gorbik <gor@linux•ibm.com>,
Aurelien Jacquiot <jacquiot.aurelien@gmail•com>,
linux-m68k@lists•linux-m68k.org,
Stafford Horne <shorne@gmail•com>,
linux-arm-kernel@lists•infradead.org,
Chris Zankel <chris@zankel•net>, Tony Luck <tony.luck@intel•com>,
Douglas Anderson <dianders@chromium•org>,
Heiko Carstens <heiko.carstens@de•ibm.com>,
Will Deacon <will@kernel•org>,
Daniel Thompson <daniel.thompson@linaro•org>,
Brian Cain <bcain@codeaurora•org>,
Christian Borntraeger <borntraeger@de•ibm.com>,
kgdb-bugreport@lists•sourceforge.net,
linux-snps-arc@lists•infradead.org,
Fenghua Yu <fenghua.yu@intel•com>, Borislav Petkov <bp@alien8•de>,
Jeff Dike <jdike@addtoit•com>,
Steven Rostedt <rostedt@goodmis•org>,
Ivan Kokshaysky <ink@jurassic•park.msu.ru>,
Greentime Hu <green.hu@gmail•com>, Guan Xuetao <gxt@pku•edu.cn>,
linux-parisc@vger•kernel.org, linux-alpha@vger•kernel.org,
Ley Foon Tan <lftan@altera•com>,
"David S. Miller" <davem@davemloft•net>,
Rich Felker <dalias@libc•org>, Petr Mladek <pmladek@suse•com>,
Peter Zijlstra <peterz@infradead•org>,
"H. Peter Anvin" <hpa@zytor•com>,
sparclinux@vger•kernel.org, linux-riscv@lists•infradead.org,
Anton Ivanov <anton.ivanov@cambridgegreys•com>,
Jonas Bonn <jonas@southpole•se>,
Richard Weinberger <richard@nod•at>, X86 ML <x86@kernel•org>,
clang-built-linux@googlegroups•com,
Ingo Molnar <mingo@redhat•com>, Mark Salter <msalter@redhat•com>,
Albert Ou <aou@eecs•berkeley.edu>,
Stefan Kristiansson <stefan.kristiansson@saunalahti•fi>,
openrisc@lists•librecores.org,
Paul Walmsley <paul.walmsley@sifive•com>,
Michal Simek <monstr@monstr•eu>,
Vineet Gupta <vgupta@synopsys•com>,
linux-mips@vger•kernel.org,
Sergey Senozhatsky <sergey.senozhatsky@gmail•com>,
Palmer Dabbelt <palmer@dabbelt•com>,
Jason Wessel <jason.wessel@windriver•com>,
nios2-dev@lists•rocketboards.org, linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH 00/50] Add log level to show_stack()
Date: Fri, 8 Nov 2019 21:08:30 +0000 [thread overview]
Message-ID: <5a411348-be84-f592-ef2d-ffaec99332bd@gmail.com> (raw)
In-Reply-To: <20191108173045.GY25745@shell.armlinux.org.uk>
On 11/8/19 5:30 PM, Russell King - ARM Linux admin wrote:
> On Fri, Nov 08, 2019 at 04:28:30PM +0000, Dmitry Safonov wrote:
[..]
>>
>> Well, the use-case for lower log-level is that everything goes into logs
>> (/var/log/dmesg or /var/log/messages whatever rsyslog has settting).
>>
>> That has it's value:
>> - after a failure (i.e. panic) messages, those were only signs that
>> something goes wrong can be seen in logs which can give ideas what has
>> happened.
>
> No they don't. When the kernel panics, userspace generally stops
> running, so rsyslog won't be able to write them to /var/log/messages.
>
> How, by "kernel panics" I mean a real kernel panic, which probably
> isn't what you're talking about there. You are probably talking
> about the whole shebang of non-fatal kernel oops, kernel warnings
> and the like. If so, I'd ask you to stop confuzzilating terminology.
>
> If you really want to capture such events, then you need to have the
> kernel write the panic to (e.g.) flash - see the mtdoops driver.
I was talking about things prior the panic: OOMs, MMC write/read
warnings, hung tasks, we also have local patches to produce a warning if
the mutex is being held for too long or a task is starving on CPU time
by hard/soft irqs (I hope I will design something like that for
upstream). I've found those warnings useful to:
(a) have an early message when the things are starting going bad.
(b) analyze contentions or too large scale for a box or faulty hardware
for non-reproducible issues just from logs.
We use kexec to save the dmesg ringbuffer content after the panic.
Thanks,
Dmitry
next prev parent reply other threads:[~2019-11-09 1:31 UTC|newest]
Thread overview: 39+ 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 26/50] powerpc: Add show_stack_loglvl() Dmitry Safonov
2019-11-06 9:52 ` Michael Ellerman
2019-11-06 16:01 ` 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
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 [this message]
2019-11-13 15:41 ` Steven Rostedt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5a411348-be84-f592-ef2d-ffaec99332bd@gmail.com \
--to=0x7f454c46@gmail$(echo .)com \
--cc=James.Bottomley@hansenpartnership$(echo .)com \
--cc=akpm@linux-foundation$(echo .)org \
--cc=anton.ivanov@cambridgegreys$(echo .)com \
--cc=aou@eecs$(echo .)berkeley.edu \
--cc=bcain@codeaurora$(echo .)org \
--cc=borntraeger@de$(echo .)ibm.com \
--cc=bp@alien8$(echo .)de \
--cc=bsegall@google$(echo .)com \
--cc=catalin.marinas@arm$(echo .)com \
--cc=chris@zankel$(echo .)net \
--cc=clang-built-linux@googlegroups$(echo .)com \
--cc=dalias@libc$(echo .)org \
--cc=daniel.thompson@linaro$(echo .)org \
--cc=davem@davemloft$(echo .)net \
--cc=deanbo422@gmail$(echo .)com \
--cc=deller@gmx$(echo .)de \
--cc=dianders@chromium$(echo .)org \
--cc=dietmar.eggemann@arm$(echo .)com \
--cc=dima@arista$(echo .)com \
--cc=fenghua.yu@intel$(echo .)com \
--cc=geert@linux-m68k$(echo .)org \
--cc=gor@linux$(echo .)ibm.com \
--cc=green.hu@gmail$(echo .)com \
--cc=gregkh@linuxfoundation$(echo .)org \
--cc=guoren@kernel$(echo .)org \
--cc=gxt@pku$(echo .)edu.cn \
--cc=heiko.carstens@de$(echo .)ibm.com \
--cc=hpa@zytor$(echo .)com \
--cc=ink@jurassic$(echo .)park.msu.ru \
--cc=jacquiot.aurelien@gmail$(echo .)com \
--cc=jason.wessel@windriver$(echo .)com \
--cc=jcmvbkbc@gmail$(echo .)com \
--cc=jdike@addtoit$(echo .)com \
--cc=jhogan@kernel$(echo .)org \
--cc=jonas@southpole$(echo .)se \
--cc=jslaby@suse$(echo .)com \
--cc=juri.lelli@redhat$(echo .)com \
--cc=kgdb-bugreport@lists$(echo .)sourceforge.net \
--cc=len.brown@intel$(echo .)com \
--cc=lftan@altera$(echo .)com \
--cc=linux-alpha@vger$(echo .)kernel.org \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
--cc=linux-c6x-dev@linux-c6x$(echo .)org \
--cc=linux-hexagon@vger$(echo .)kernel.org \
--cc=linux-ia64@vger$(echo .)kernel.org \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linux-m68k@lists$(echo .)linux-m68k.org \
--cc=linux-mips@vger$(echo .)kernel.org \
--cc=linux-parisc@vger$(echo .)kernel.org \
--cc=linux-pm@vger$(echo .)kernel.org \
--cc=linux-riscv@lists$(echo .)infradead.org \
--cc=linux-s390@vger$(echo .)kernel.org \
--cc=linux-sh@vger$(echo .)kernel.org \
--cc=linux-snps-arc@lists$(echo .)infradead.org \
--cc=linux-um@lists$(echo .)infradead.org \
--cc=linux-xtensa@linux-xtensa$(echo .)org \
--cc=linux@armlinux$(echo .)org.uk \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=mattst88@gmail$(echo .)com \
--cc=mgorman@suse$(echo .)de \
--cc=mingo@kernel$(echo .)org \
--cc=mingo@redhat$(echo .)com \
--cc=monstr@monstr$(echo .)eu \
--cc=msalter@redhat$(echo .)com \
--cc=nios2-dev@lists$(echo .)rocketboards.org \
--cc=openrisc@lists$(echo .)librecores.org \
--cc=palmer@dabbelt$(echo .)com \
--cc=paul.walmsley@sifive$(echo .)com \
--cc=paulburton@kernel$(echo .)org \
--cc=paulus@samba$(echo .)org \
--cc=pavel@ucw$(echo .)cz \
--cc=penguin-kernel@i-love$(echo .)sakura.ne.jp \
--cc=peterz@infradead$(echo .)org \
--cc=pmladek@suse$(echo .)com \
--cc=ralf@linux-mips$(echo .)org \
--cc=richard@nod$(echo .)at \
--cc=rjw@rjwysocki$(echo .)net \
--cc=rostedt@goodmis$(echo .)org \
--cc=rth@twiddle$(echo .)net \
--cc=sergey.senozhatsky@gmail$(echo .)com \
--cc=shorne@gmail$(echo .)com \
--cc=sparclinux@vger$(echo .)kernel.org \
--cc=stefan.kristiansson@saunalahti$(echo .)fi \
--cc=tglx@linutronix$(echo .)de \
--cc=tony.luck@intel$(echo .)com \
--cc=uclinux-h8-devel@lists$(echo .)sourceforge.jp \
--cc=vgupta@synopsys$(echo .)com \
--cc=vincent.guittot@linaro$(echo .)org \
--cc=will@kernel$(echo .)org \
--cc=x86@kernel$(echo .)org \
--cc=ysato@users$(echo .)sourceforge.jp \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox