* [PATCH] kexec: dump kmessage before machine_kexec
@ 2020-06-05 19:46 Pavel Tatashin
2020-06-05 21:26 ` Kees Cook
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Pavel Tatashin @ 2020-06-05 19:46 UTC (permalink / raw)
To: pasha.tatashin, jmorris, sashal, pmladek, ebiederm, keescook,
anton, ccross, tony.luck, kexec, linux-kernel
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:
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@soleen.com>
---
kernel/kexec_core.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index c19c0dad1ebe..50027f759a97 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/frame.h>
+#include <linux/kmsg_dump.h>
#include <asm/page.h>
#include <asm/sections.h>
@@ -1181,6 +1182,7 @@ int kernel_kexec(void)
machine_shutdown();
}
+ kmsg_dump(KMSG_DUMP_SHUTDOWN);
machine_kexec(kexec_image);
#ifdef CONFIG_KEXEC_JUMP
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] kexec: dump kmessage before machine_kexec
2020-06-05 19:46 [PATCH] kexec: dump kmessage before machine_kexec Pavel Tatashin
@ 2020-06-05 21:26 ` Kees Cook
2020-06-08 8:06 ` Petr Mladek
2020-06-08 8:07 ` Bhupesh Sharma
2 siblings, 0 replies; 4+ messages in thread
From: Kees Cook @ 2020-06-05 21:26 UTC (permalink / raw)
To: Pavel Tatashin
Cc: jmorris, sashal, pmladek, ebiederm, anton, ccross, tony.luck,
kexec, linux-kernel
On Fri, Jun 05, 2020 at 03:46:42PM -0400, Pavel Tatashin wrote:
> 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:
>
> 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@soleen.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] kexec: dump kmessage before machine_kexec
2020-06-05 19:46 [PATCH] kexec: dump kmessage before machine_kexec Pavel Tatashin
2020-06-05 21:26 ` Kees Cook
@ 2020-06-08 8:06 ` Petr Mladek
2020-06-08 8:07 ` Bhupesh Sharma
2 siblings, 0 replies; 4+ messages in thread
From: Petr Mladek @ 2020-06-08 8:06 UTC (permalink / raw)
To: Pavel Tatashin
Cc: jmorris, sashal, ebiederm, keescook, anton, ccross, tony.luck,
kexec, linux-kernel
On Fri 2020-06-05 15:46:42, Pavel Tatashin wrote:
> 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:
>
> 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@soleen.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Best Regards,
Petr
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] kexec: dump kmessage before machine_kexec
2020-06-05 19:46 [PATCH] kexec: dump kmessage before machine_kexec Pavel Tatashin
2020-06-05 21:26 ` Kees Cook
2020-06-08 8:06 ` Petr Mladek
@ 2020-06-08 8:07 ` Bhupesh Sharma
2 siblings, 0 replies; 4+ messages in thread
From: Bhupesh Sharma @ 2020-06-08 8:07 UTC (permalink / raw)
To: Pavel Tatashin
Cc: James Morris, sashal, pmladek, Eric Biederman, Kees Cook, anton,
ccross, Luck, Tony, kexec mailing list,
Linux Kernel Mailing List
Hi Pavel,
On Sat, Jun 6, 2020 at 1:16 AM Pavel Tatashin <pasha.tatashin@soleen.com> wrote:
>
> 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:
>
> 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@soleen.com>
> ---
> kernel/kexec_core.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index c19c0dad1ebe..50027f759a97 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/frame.h>
> +#include <linux/kmsg_dump.h>
>
> #include <asm/page.h>
> #include <asm/sections.h>
> @@ -1181,6 +1182,7 @@ int kernel_kexec(void)
> machine_shutdown();
> }
>
> + kmsg_dump(KMSG_DUMP_SHUTDOWN);
> machine_kexec(kexec_image);
>
> #ifdef CONFIG_KEXEC_JUMP
> --
> 2.25.1
LGTM, so:
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-06-05 19:46 [PATCH] kexec: dump kmessage before machine_kexec Pavel Tatashin
2020-06-05 21:26 ` Kees Cook
2020-06-08 8:06 ` Petr Mladek
2020-06-08 8:07 ` Bhupesh Sharma
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