* [PATCH V2] Documentation: Improve crash_kexec_post_notifiers description
@ 2024-08-30 18:21 Guilherme G. Piccoli
2024-09-02 3:05 ` Baoquan He
2024-09-02 8:23 ` Simon Horman
0 siblings, 2 replies; 6+ messages in thread
From: Guilherme G. Piccoli @ 2024-08-30 18:21 UTC (permalink / raw)
To: kexec, linux-doc
Cc: bhe, vgoyal, dyoung, corbet, linux-kernel, linux-debuggers,
stephen.s.brennan, kernel, kernel-dev, Guilherme G. Piccoli
Be more clear about the downsides, the upsides (yes, there are some!)
and about code that unconditionally sets that.
Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
---
V2: Some wording improvements from Stephen, thanks!
Also added his review tag.
V1 link: https://lore.kernel.org/r/20240830140401.458542-1-gpiccoli@igalia.com/
Documentation/admin-guide/kernel-parameters.txt | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index efc52ddc6864..351730108c58 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -913,12 +913,16 @@
the parameter has no effect.
crash_kexec_post_notifiers
- Run kdump after running panic-notifiers and dumping
- kmsg. This only for the users who doubt kdump always
- succeeds in any situation.
- Note that this also increases risks of kdump failure,
- because some panic notifiers can make the crashed
- kernel more unstable.
+ Only jump to kdump kernel after running the panic
+ notifiers and dumping kmsg. This option increases the
+ risks of a kdump failure, since some panic notifiers
+ can make the crashed kernel more unstable. In the
+ configurations where kdump may not be reliable,
+ running the panic notifiers can allow collecting more
+ data on dmesg, like stack traces from other CPUS or
+ extra data dumped by panic_print. Notice that some
+ code enables this option unconditionally, like
+ Hyper-V, PowerPC (fadump) and AMD SEV.
crashkernel=size[KMG][@offset[KMG]]
[KNL,EARLY] Using kexec, Linux can switch to a 'crash kernel'
--
2.46.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH V2] Documentation: Improve crash_kexec_post_notifiers description
2024-08-30 18:21 [PATCH V2] Documentation: Improve crash_kexec_post_notifiers description Guilherme G. Piccoli
@ 2024-09-02 3:05 ` Baoquan He
2024-09-11 15:09 ` Guilherme G. Piccoli
2024-09-02 8:23 ` Simon Horman
1 sibling, 1 reply; 6+ messages in thread
From: Baoquan He @ 2024-09-02 3:05 UTC (permalink / raw)
To: Guilherme G. Piccoli
Cc: kexec, linux-doc, vgoyal, dyoung, corbet, linux-kernel,
linux-debuggers, stephen.s.brennan, kernel, kernel-dev
On 08/30/24 at 03:21pm, Guilherme G. Piccoli wrote:
> Be more clear about the downsides, the upsides (yes, there are some!)
> and about code that unconditionally sets that.
>
> Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
>
> ---
>
> V2: Some wording improvements from Stephen, thanks!
> Also added his review tag.
>
> V1 link: https://lore.kernel.org/r/20240830140401.458542-1-gpiccoli@igalia.com/
>
>
> Documentation/admin-guide/kernel-parameters.txt | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index efc52ddc6864..351730108c58 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -913,12 +913,16 @@
> the parameter has no effect.
>
> crash_kexec_post_notifiers
> - Run kdump after running panic-notifiers and dumping
> - kmsg. This only for the users who doubt kdump always
> - succeeds in any situation.
> - Note that this also increases risks of kdump failure,
> - because some panic notifiers can make the crashed
> - kernel more unstable.
> + Only jump to kdump kernel after running the panic
> + notifiers and dumping kmsg. This option increases the
> + risks of a kdump failure, since some panic notifiers
> + can make the crashed kernel more unstable. In the
> + configurations where kdump may not be reliable,
> + running the panic notifiers can allow collecting more
> + data on dmesg, like stack traces from other CPUS or
> + extra data dumped by panic_print. Notice that some
> + code enables this option unconditionally, like
> + Hyper-V, PowerPC (fadump) and AMD SEV.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I know Hyper-V enable panic-notifiers by default, but don't remember how
PowerPC and AMD SEC behave in this aspect. While at it, can you add a
little more words to state them in log so that people can learn it?
Thanks.
>
> crashkernel=size[KMG][@offset[KMG]]
> [KNL,EARLY] Using kexec, Linux can switch to a 'crash kernel'
> --
> 2.46.0
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH V2] Documentation: Improve crash_kexec_post_notifiers description
2024-08-30 18:21 [PATCH V2] Documentation: Improve crash_kexec_post_notifiers description Guilherme G. Piccoli
2024-09-02 3:05 ` Baoquan He
@ 2024-09-02 8:23 ` Simon Horman
2024-09-11 15:10 ` Guilherme G. Piccoli
1 sibling, 1 reply; 6+ messages in thread
From: Simon Horman @ 2024-09-02 8:23 UTC (permalink / raw)
To: Guilherme G. Piccoli
Cc: kexec, linux-doc, bhe, corbet, kernel, linux-kernel,
stephen.s.brennan, kernel-dev, dyoung, vgoyal, linux-debuggers
On Fri, Aug 30, 2024 at 03:21:00PM -0300, Guilherme G. Piccoli wrote:
> Be more clear about the downsides, the upsides (yes, there are some!)
> and about code that unconditionally sets that.
>
> Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
>
> ---
>
> V2: Some wording improvements from Stephen, thanks!
> Also added his review tag.
>
> V1 link: https://lore.kernel.org/r/20240830140401.458542-1-gpiccoli@igalia.com/
>
>
> Documentation/admin-guide/kernel-parameters.txt | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
Hi Guilherme,
Some subjective grammar nits.
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index efc52ddc6864..351730108c58 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -913,12 +913,16 @@
> the parameter has no effect.
>
> crash_kexec_post_notifiers
> - Run kdump after running panic-notifiers and dumping
> - kmsg. This only for the users who doubt kdump always
> - succeeds in any situation.
> - Note that this also increases risks of kdump failure,
> - because some panic notifiers can make the crashed
> - kernel more unstable.
> + Only jump to kdump kernel after running the panic
> + notifiers and dumping kmsg. This option increases the
> + risks of a kdump failure, since some panic notifiers
> + can make the crashed kernel more unstable. In the
nit: In the configurations -> In configurations
> + configurations where kdump may not be reliable,
> + running the panic notifiers can allow collecting more
> + data on dmesg, like stack traces from other CPUS or
> + extra data dumped by panic_print. Notice that some
nit: Notice that -> Note that
> + code enables this option unconditionally, like
Maybe: some code enables -> some configurations enable
> + Hyper-V, PowerPC (fadump) and AMD SEV.
>
> crashkernel=size[KMG][@offset[KMG]]
> [KNL,EARLY] Using kexec, Linux can switch to a 'crash kernel'
> --
> 2.46.0
>
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH V2] Documentation: Improve crash_kexec_post_notifiers description
2024-09-02 3:05 ` Baoquan He
@ 2024-09-11 15:09 ` Guilherme G. Piccoli
2024-09-12 0:54 ` Baoquan He
0 siblings, 1 reply; 6+ messages in thread
From: Guilherme G. Piccoli @ 2024-09-11 15:09 UTC (permalink / raw)
To: Baoquan He
Cc: kexec, linux-doc, vgoyal, dyoung, corbet, linux-kernel,
linux-debuggers, stephen.s.brennan, kernel, kernel-dev
On 02/09/2024 05:05, Baoquan He wrote:
> On 08/30/24 at 03:21pm, Guilherme G. Piccoli wrote:
>> Be more clear about the downsides, the upsides (yes, there are some!)
>> and about code that unconditionally sets that.
>>
>> Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
>> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
>>
>> ---
>>
>> V2: Some wording improvements from Stephen, thanks!
>> Also added his review tag.
>>
>> V1 link: https://lore.kernel.org/r/20240830140401.458542-1-gpiccoli@igalia.com/
>>
>>
>> Documentation/admin-guide/kernel-parameters.txt | 16 ++++++++++------
>> 1 file changed, 10 insertions(+), 6 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index efc52ddc6864..351730108c58 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -913,12 +913,16 @@
>> the parameter has no effect.
>>
>> crash_kexec_post_notifiers
>> - Run kdump after running panic-notifiers and dumping
>> - kmsg. This only for the users who doubt kdump always
>> - succeeds in any situation.
>> - Note that this also increases risks of kdump failure,
>> - because some panic notifiers can make the crashed
>> - kernel more unstable.
>> + Only jump to kdump kernel after running the panic
>> + notifiers and dumping kmsg. This option increases the
>> + risks of a kdump failure, since some panic notifiers
>> + can make the crashed kernel more unstable. In the
>> + configurations where kdump may not be reliable,
>> + running the panic notifiers can allow collecting more
>> + data on dmesg, like stack traces from other CPUS or
>> + extra data dumped by panic_print. Notice that some
>> + code enables this option unconditionally, like
>> + Hyper-V, PowerPC (fadump) and AMD SEV.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> I know Hyper-V enable panic-notifiers by default, but don't remember how
> PowerPC and AMD SEC behave in this aspect. While at it, can you add a
> little more words to state them in log so that people can learn it?
> Thanks.
>
Hi Baoquan, tnx for the suggestion! You mean mention that in the commit
message? If so, I can certainly do - will sent a new version soon(tm)
and include it =)
Cheers,
Guilherme
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH V2] Documentation: Improve crash_kexec_post_notifiers description
2024-09-02 8:23 ` Simon Horman
@ 2024-09-11 15:10 ` Guilherme G. Piccoli
0 siblings, 0 replies; 6+ messages in thread
From: Guilherme G. Piccoli @ 2024-09-11 15:10 UTC (permalink / raw)
To: Simon Horman
Cc: kexec, linux-doc, bhe, corbet, kernel, linux-kernel,
stephen.s.brennan, kernel-dev, dyoung, vgoyal, linux-debuggers
On 02/09/2024 10:23, Simon Horman wrote:
>
> Hi Guilherme,
>
> Some subjective grammar nits.
>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index efc52ddc6864..351730108c58 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -913,12 +913,16 @@
>> the parameter has no effect.
>>
>> crash_kexec_post_notifiers
>> - Run kdump after running panic-notifiers and dumping
>> - kmsg. This only for the users who doubt kdump always
>> - succeeds in any situation.
>> - Note that this also increases risks of kdump failure,
>> - because some panic notifiers can make the crashed
>> - kernel more unstable.
>> + Only jump to kdump kernel after running the panic
>> + notifiers and dumping kmsg. This option increases the
>> + risks of a kdump failure, since some panic notifiers
>> + can make the crashed kernel more unstable. In the
>
> nit: In the configurations -> In configurations
>
>> + configurations where kdump may not be reliable,
>> + running the panic notifiers can allow collecting more
>> + data on dmesg, like stack traces from other CPUS or
>> + extra data dumped by panic_print. Notice that some
>
> nit: Notice that -> Note that
>
>> + code enables this option unconditionally, like
>
> Maybe: some code enables -> some configurations enable
>
Hey Simon, tnx for the suggestions, will change in the next version.
Cheers,
Guilherme
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH V2] Documentation: Improve crash_kexec_post_notifiers description
2024-09-11 15:09 ` Guilherme G. Piccoli
@ 2024-09-12 0:54 ` Baoquan He
0 siblings, 0 replies; 6+ messages in thread
From: Baoquan He @ 2024-09-12 0:54 UTC (permalink / raw)
To: Guilherme G. Piccoli
Cc: kexec, linux-doc, vgoyal, dyoung, corbet, linux-kernel,
linux-debuggers, stephen.s.brennan, kernel, kernel-dev
On 09/11/24 at 05:09pm, Guilherme G. Piccoli wrote:
> On 02/09/2024 05:05, Baoquan He wrote:
> > On 08/30/24 at 03:21pm, Guilherme G. Piccoli wrote:
> >> Be more clear about the downsides, the upsides (yes, there are some!)
> >> and about code that unconditionally sets that.
> >>
> >> Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
> >> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
> >>
> >> ---
> >>
> >> V2: Some wording improvements from Stephen, thanks!
> >> Also added his review tag.
> >>
> >> V1 link: https://lore.kernel.org/r/20240830140401.458542-1-gpiccoli@igalia.com/
> >>
> >>
> >> Documentation/admin-guide/kernel-parameters.txt | 16 ++++++++++------
> >> 1 file changed, 10 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> >> index efc52ddc6864..351730108c58 100644
> >> --- a/Documentation/admin-guide/kernel-parameters.txt
> >> +++ b/Documentation/admin-guide/kernel-parameters.txt
> >> @@ -913,12 +913,16 @@
> >> the parameter has no effect.
> >>
> >> crash_kexec_post_notifiers
> >> - Run kdump after running panic-notifiers and dumping
> >> - kmsg. This only for the users who doubt kdump always
> >> - succeeds in any situation.
> >> - Note that this also increases risks of kdump failure,
> >> - because some panic notifiers can make the crashed
> >> - kernel more unstable.
> >> + Only jump to kdump kernel after running the panic
> >> + notifiers and dumping kmsg. This option increases the
> >> + risks of a kdump failure, since some panic notifiers
> >> + can make the crashed kernel more unstable. In the
> >> + configurations where kdump may not be reliable,
> >> + running the panic notifiers can allow collecting more
> >> + data on dmesg, like stack traces from other CPUS or
> >> + extra data dumped by panic_print. Notice that some
> >> + code enables this option unconditionally, like
> >> + Hyper-V, PowerPC (fadump) and AMD SEV.
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > I know Hyper-V enable panic-notifiers by default, but don't remember how
> > PowerPC and AMD SEC behave in this aspect. While at it, can you add a
> > little more words to state them in log so that people can learn it?
> > Thanks.
> >
> Hi Baoquan, tnx for the suggestion! You mean mention that in the commit
> message? If so, I can certainly do - will sent a new version soon(tm)
> and include it =)
You are right, thanks for the effort.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2024-08-30 18:21 [PATCH V2] Documentation: Improve crash_kexec_post_notifiers description Guilherme G. Piccoli
2024-09-02 3:05 ` Baoquan He
2024-09-11 15:09 ` Guilherme G. Piccoli
2024-09-12 0:54 ` Baoquan He
2024-09-02 8:23 ` Simon Horman
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