* core sysctl @ 2020-05-25 15:08 Jonny Grant 2020-05-27 13:06 ` Michael Kerrisk (man-pages) 0 siblings, 1 reply; 9+ messages in thread From: Jonny Grant @ 2020-05-25 15:08 UTC (permalink / raw) To: Michael Kerrisk, linux-man Suggestion for some additional information on this page: http://man7.org/linux/man-pages/man5/core.5.html Could "Core dumps and systemd" be extended to give an example of sysctl making a temporary change? eg set to the filename and signal that causes the core dump: # sysctl -w kernel.core_pattern="%e-%s.core" Cheers, Jonny ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: core sysctl 2020-05-25 15:08 core sysctl Jonny Grant @ 2020-05-27 13:06 ` Michael Kerrisk (man-pages) 2020-05-27 13:23 ` Jonny Grant 0 siblings, 1 reply; 9+ messages in thread From: Michael Kerrisk (man-pages) @ 2020-05-27 13:06 UTC (permalink / raw) To: Jonny Grant; +Cc: linux-man Hi Jonny, On Mon, 25 May 2020 at 17:08, Jonny Grant <jg@jguk.org> wrote: > > Suggestion for some additional information on this page: > > http://man7.org/linux/man-pages/man5/core.5.html > > Could "Core dumps and systemd" be extended to give an > example of sysctl making a temporary change? > > eg set to the filename and signal that causes the core dump: > > # sysctl -w kernel.core_pattern="%e-%s.core" I'm a little confused: what do you mean by "making a *temporary* change" (i.e., where does "temporary" come into it)? Thanks, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: core sysctl 2020-05-27 13:06 ` Michael Kerrisk (man-pages) @ 2020-05-27 13:23 ` Jonny Grant 2020-05-27 13:32 ` Michael Kerrisk (man-pages) 0 siblings, 1 reply; 9+ messages in thread From: Jonny Grant @ 2020-05-27 13:23 UTC (permalink / raw) To: mtk.manpages; +Cc: linux-man On 27/05/2020 14:06, Michael Kerrisk (man-pages) wrote: > Hi Jonny, > > On Mon, 25 May 2020 at 17:08, Jonny Grant <jg@jguk.org> wrote: >> >> Suggestion for some additional information on this page: >> >> http://man7.org/linux/man-pages/man5/core.5.html >> >> Could "Core dumps and systemd" be extended to give an >> example of sysctl making a temporary change? >> >> eg set to the filename and signal that causes the core dump: >> >> # sysctl -w kernel.core_pattern="%e-%s.core" > > I'm a little confused: what do you mean by "making a *temporary* > change" (i.e., where does "temporary" come into it)? > > Thanks, > > Michael > As I understood, this core pattern is set until reboot. For a permanent change, I set in this file: /etc/sysctl.d/99-sysctl.conf Cheers, Jonny ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: core sysctl 2020-05-27 13:23 ` Jonny Grant @ 2020-05-27 13:32 ` Michael Kerrisk (man-pages) 2020-05-27 15:22 ` Jonny Grant 0 siblings, 1 reply; 9+ messages in thread From: Michael Kerrisk (man-pages) @ 2020-05-27 13:32 UTC (permalink / raw) To: Jonny Grant; +Cc: linux-man Hi Jonny On Wed, 27 May 2020 at 15:23, Jonny Grant <jg@jguk.org> wrote: > > > > On 27/05/2020 14:06, Michael Kerrisk (man-pages) wrote: > > Hi Jonny, > > > > On Mon, 25 May 2020 at 17:08, Jonny Grant <jg@jguk.org> wrote: > >> > >> Suggestion for some additional information on this page: > >> > >> http://man7.org/linux/man-pages/man5/core.5.html > >> > >> Could "Core dumps and systemd" be extended to give an > >> example of sysctl making a temporary change? > >> > >> eg set to the filename and signal that causes the core dump: > >> > >> # sysctl -w kernel.core_pattern="%e-%s.core" > > > > I'm a little confused: what do you mean by "making a *temporary* > > change" (i.e., where does "temporary" come into it)? > > > > Thanks, > > > > Michael > > > > As I understood, this core pattern is set until reboot. Okay, now I understand. Next question: what's the value in having the signal number in the filename? Thanks, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: core sysctl 2020-05-27 13:32 ` Michael Kerrisk (man-pages) @ 2020-05-27 15:22 ` Jonny Grant 2020-05-28 9:16 ` Michael Kerrisk (man-pages) 0 siblings, 1 reply; 9+ messages in thread From: Jonny Grant @ 2020-05-27 15:22 UTC (permalink / raw) To: mtk.manpages; +Cc: linux-man On 27/05/2020 14:32, Michael Kerrisk (man-pages) wrote: > Hi Jonny > > On Wed, 27 May 2020 at 15:23, Jonny Grant <jg@jguk.org> wrote: >> >> >> >> On 27/05/2020 14:06, Michael Kerrisk (man-pages) wrote: >>> Hi Jonny, >>> >>> On Mon, 25 May 2020 at 17:08, Jonny Grant <jg@jguk.org> wrote: >>>> >>>> Suggestion for some additional information on this page: >>>> >>>> http://man7.org/linux/man-pages/man5/core.5.html >>>> >>>> Could "Core dumps and systemd" be extended to give an >>>> example of sysctl making a temporary change? >>>> >>>> eg set to the filename and signal that causes the core dump: >>>> >>>> # sysctl -w kernel.core_pattern="%e-%s.core" >>> >>> I'm a little confused: what do you mean by "making a *temporary* >>> change" (i.e., where does "temporary" come into it)? >>> >>> Thanks, >>> >>> Michael >>> >> >> As I understood, this core pattern is set until reboot. > > Okay, now I understand. Next question: what's the value in having the > signal number in the filename? The signal number indicates the reason the core was dumped, eg 11 SIGSEGV, SIGTRAP is 5. %P %t %I also useful. Cheers, Jonny ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: core sysctl 2020-05-27 15:22 ` Jonny Grant @ 2020-05-28 9:16 ` Michael Kerrisk (man-pages) 2020-05-28 9:28 ` Jakub Wilk 2020-05-28 9:51 ` Jonny Grant 0 siblings, 2 replies; 9+ messages in thread From: Michael Kerrisk (man-pages) @ 2020-05-28 9:16 UTC (permalink / raw) To: Jonny Grant; +Cc: mtk.manpages, linux-man Hello Jonny, On 5/27/20 5:22 PM, Jonny Grant wrote: > > > On 27/05/2020 14:32, Michael Kerrisk (man-pages) wrote: >> Hi Jonny >> >> On Wed, 27 May 2020 at 15:23, Jonny Grant <jg@jguk.org> wrote: >>> >>> >>> >>> On 27/05/2020 14:06, Michael Kerrisk (man-pages) wrote: >>>> Hi Jonny, >>>> >>>> On Mon, 25 May 2020 at 17:08, Jonny Grant <jg@jguk.org> wrote: >>>>> >>>>> Suggestion for some additional information on this page: >>>>> >>>>> http://man7.org/linux/man-pages/man5/core.5.html >>>>> >>>>> Could "Core dumps and systemd" be extended to give an >>>>> example of sysctl making a temporary change? >>>>> >>>>> eg set to the filename and signal that causes the core dump: >>>>> >>>>> # sysctl -w kernel.core_pattern="%e-%s.core" >>>> >>>> I'm a little confused: what do you mean by "making a *temporary* >>>> change" (i.e., where does "temporary" come into it)? >>>> >>>> Thanks, >>>> >>>> Michael >>>> >>> >>> As I understood, this core pattern is set until reboot. >> >> Okay, now I understand. Next question: what's the value in having the >> signal number in the filename? > > The signal number indicates the reason the core was dumped, > eg 11 SIGSEGV, SIGTRAP is 5. Sure, it tells us what signal triggered the core dump. My reason for the question was that it doesn't tell us the *reason* for the core dump--for example, SIGSEGV can be generated for many reasons. > %P %t %I also useful. Okay. I applied the patch below. Thanks, Michael diff --git a/man5/core.5 b/man5/core.5 index 9725ff64a..6dbaa69b8 100644 --- a/man5/core.5 +++ b/man5/core.5 @@ -533,7 +533,7 @@ For more extensive details, see the .BR coredumpctl (1) manual page. .PP -To disable the +To (persistently) disable the .BR systemd (1) mechanism that archives core dumps, restoring to something more like traditional Linux behavior, one can set an override for the @@ -548,6 +548,18 @@ mechanism, using something like: .EE .in .PP +It is also possible to temporarily (i.e., until the next reboot) change the +.I core_patter +setting using a command such as the following +(which causes the names of core dump files to include the executable name +as well as the number of the signal which triggered the core dump): +.PP +.in +4n +.EX +# \fBsysctl \-w kernel.core_pattern="%e\-%s.core"\fP +.EE +.in +.PP .\" .SH NOTES The -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: core sysctl 2020-05-28 9:16 ` Michael Kerrisk (man-pages) @ 2020-05-28 9:28 ` Jakub Wilk 2020-05-28 9:38 ` Michael Kerrisk (man-pages) 2020-05-28 9:51 ` Jonny Grant 1 sibling, 1 reply; 9+ messages in thread From: Jakub Wilk @ 2020-05-28 9:28 UTC (permalink / raw) To: Michael Kerrisk; +Cc: Jonny Grant, linux-man * Michael Kerrisk <mtk.manpages@gmail.com>, 2020-05-28, 11:16: >+.I core_patter Trailing "n" is missing. -- Jakub Wilk ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: core sysctl 2020-05-28 9:28 ` Jakub Wilk @ 2020-05-28 9:38 ` Michael Kerrisk (man-pages) 0 siblings, 0 replies; 9+ messages in thread From: Michael Kerrisk (man-pages) @ 2020-05-28 9:38 UTC (permalink / raw) To: Jakub Wilk; +Cc: mtk.manpages, Jonny Grant, linux-man On 5/28/20 11:28 AM, Jakub Wilk wrote: > * Michael Kerrisk <mtk.manpages@gmail.com>, 2020-05-28, 11:16: >> +.I core_patter > > Trailing "n" is missing. Thanks, Jakub. -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: core sysctl 2020-05-28 9:16 ` Michael Kerrisk (man-pages) 2020-05-28 9:28 ` Jakub Wilk @ 2020-05-28 9:51 ` Jonny Grant 1 sibling, 0 replies; 9+ messages in thread From: Jonny Grant @ 2020-05-28 9:51 UTC (permalink / raw) To: Michael Kerrisk (man-pages); +Cc: linux-man On 28/05/2020 10:16, Michael Kerrisk (man-pages) wrote: > Hello Jonny, > > On 5/27/20 5:22 PM, Jonny Grant wrote: >> >> >> On 27/05/2020 14:32, Michael Kerrisk (man-pages) wrote: >>> Hi Jonny >>> >>> On Wed, 27 May 2020 at 15:23, Jonny Grant <jg@jguk.org> wrote: >>>> >>>> >>>> >>>> On 27/05/2020 14:06, Michael Kerrisk (man-pages) wrote: >>>>> Hi Jonny, >>>>> >>>>> On Mon, 25 May 2020 at 17:08, Jonny Grant <jg@jguk.org> wrote: >>>>>> >>>>>> Suggestion for some additional information on this page: >>>>>> >>>>>> http://man7.org/linux/man-pages/man5/core.5.html >>>>>> >>>>>> Could "Core dumps and systemd" be extended to give an >>>>>> example of sysctl making a temporary change? >>>>>> >>>>>> eg set to the filename and signal that causes the core dump: >>>>>> >>>>>> # sysctl -w kernel.core_pattern="%e-%s.core" >>>>> >>>>> I'm a little confused: what do you mean by "making a *temporary* >>>>> change" (i.e., where does "temporary" come into it)? >>>>> >>>>> Thanks, >>>>> >>>>> Michael >>>>> >>>> >>>> As I understood, this core pattern is set until reboot. >>> >>> Okay, now I understand. Next question: what's the value in having the >>> signal number in the filename? >> >> The signal number indicates the reason the core was dumped, > eg 11 SIGSEGV, SIGTRAP is 5. > > Sure, it tells us what signal triggered the core dump. > My reason for the question was that it doesn't tell us the > *reason* for the core dump--for example, SIGSEGV can be > generated for many reasons. Yes you're right. I'm sure you know all this already, there are a few crash handlers that uses gdb to generate a backtrace automatically. Thank you for adding the change Jonny ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2020-05-28 9:51 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-05-25 15:08 core sysctl Jonny Grant 2020-05-27 13:06 ` Michael Kerrisk (man-pages) 2020-05-27 13:23 ` Jonny Grant 2020-05-27 13:32 ` Michael Kerrisk (man-pages) 2020-05-27 15:22 ` Jonny Grant 2020-05-28 9:16 ` Michael Kerrisk (man-pages) 2020-05-28 9:28 ` Jakub Wilk 2020-05-28 9:38 ` Michael Kerrisk (man-pages) 2020-05-28 9:51 ` Jonny Grant
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