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| author | Eric DeVolder <eric.devolder@oracle.com> | 2020-04-13 16:22:04 -0500 |
|---|---|---|
| committer | Lennart Poettering <lennart@poettering.net> | 2020-05-15 23:15:26 +0200 |
| commit | f00c36641a253f4ea659ec3def5d87ba1336eb3b (patch) | |
| tree | 76f09c69c3be43f569107a128e5330a8d7864582 /man/systemd-pstore.service.xml | |
| parent | b4e1563ffb12c50ff89c063e721b76bfc89407b7 (diff) | |
| download | systemd-f00c36641a253f4ea659ec3def5d87ba1336eb3b.tar.gz | |
pstore: introduce tmpfiles.d/systemd-pstore.conf
The systemd pstore service archives the contents of /sys/fs/pstore
upon boot so that there is room for a subsequent dump. The issue is
that while the service is present, the kernel still needs to be
configured to write data into the pstore. The kernel has two
parameters, crash_kexec_post_notifiers and printk.always_kmsg_dump,
that control writes into pstore.
The crash_kexec_post_notifiers parameter enables the kernel to write
dmesg (including stack trace) into pstore upon a panic, and
printk.always_kmsg_dump parameter enables the kernel to write dmesg
upon a shutdown (shutdown, reboot, halt).
As it stands today, these parameters are not managed/manipulated by
the systemd pstore service, and are solely reliant upon the user [to
have the foresight] to set them on the kernel command line at boot, or
post boot via sysfs. Furthermore, the user would need to set these
parameters in a persistent fashion so that that they are enabled on
subsequent reboots.
This patch introduces the setting of these two kernel parameters via
the systemd tmpfiles technique.
Diffstat (limited to 'man/systemd-pstore.service.xml')
| -rw-r--r-- | man/systemd-pstore.service.xml | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/man/systemd-pstore.service.xml b/man/systemd-pstore.service.xml index 47916da521..335a3b3d18 100644 --- a/man/systemd-pstore.service.xml +++ b/man/systemd-pstore.service.xml @@ -81,6 +81,24 @@ <citerefentry><refentrytitle>pstore.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. </para> </refsect2> + + <refsect2> + <title>Controlling kernel parameters</title> + + <para> The kernel has two parameters, + <filename>/sys/module/kernel/parameters/crash_kexec_post_notifiers</filename> and + <filename>/sys/module/printk/parameters/always_kmsg_dump</filename>, + that control writes into pstore. + The crash_kexec_post_notifiers parameter enables the kernel to write + dmesg (including stack trace) into pstore upon a panic or crash, and + printk.always_kmsg_dump parameter enables the kernel to write dmesg + upon a normal shutdown (shutdown, reboot, halt). These kernel + parameters are managed via the + <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry> + mechanism, specifically the file <filename>/usr/lib/tmpfiles/systemd-pstore.conf</filename>. + </para> + </refsect2> + </refsect1> <refsect1> |