Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> writes: > kmsg_dump(KMSG_DUMP_SHUTDOWN) is called before > machine_restart(), machine_halt(), machine_power_off(), the only one that > is missing is machine_kexec(). > > The dmesg output that it contains can be used to study the shutdown > performance of both kernel and systemd during kexec reboot. > > Here is example of dmesg data collected after kexec: As long was we keep kmsg_dump out of the crash_kexec path where it completely breaks kexec on panic this seems a reasonable thing to do. On the ordinary kernel_kexec path everything is expected to be working. Is kmsg_dump expected to work after all of the device drivers are shut down? Otherwise this placement of kmsg_dump is too late. Eric > root@dplat-cp22:~# cat /sys/fs/pstore/dmesg-ramoops-0 | tail > ... > <6>[ 70.914592] psci: CPU3 killed (polled 0 ms) > <5>[ 70.915705] CPU4: shutdown > <6>[ 70.916643] psci: CPU4 killed (polled 4 ms) > <5>[ 70.917715] CPU5: shutdown > <6>[ 70.918725] psci: CPU5 killed (polled 0 ms) > <5>[ 70.919704] CPU6: shutdown > <6>[ 70.920726] psci: CPU6 killed (polled 4 ms) > <5>[ 70.921642] CPU7: shutdown > <6>[ 70.922650] psci: CPU7 killed (polled 0 ms) > > Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> > Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> > Reviewed-by: Petr Mladek <pmladek@xxxxxxxx> > Reviewed-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx> > --- > kernel/kexec_core.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c > index 4f8efc278aa7..e253c8b59145 100644 > --- a/kernel/kexec_core.c > +++ b/kernel/kexec_core.c > @@ -37,6 +37,7 @@ > #include <linux/compiler.h> > #include <linux/hugetlb.h> > #include <linux/objtool.h> > +#include <linux/kmsg_dump.h> > > #include <asm/page.h> > #include <asm/sections.h> > @@ -1180,6 +1181,7 @@ int kernel_kexec(void) > machine_shutdown(); > } > > + kmsg_dump(KMSG_DUMP_SHUTDOWN); > machine_kexec(kexec_image); > > #ifdef CONFIG_KEXEC_JUMP _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
