Documentation/admin-guide/kernel-parameters.txt | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)
Be more clear about the downsides, the upsides (yes, there are some!)
and about code that unconditionally sets that.
Signed-off-by: Guilherme G. Piccoli <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..cb25dc5cbe9a 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. As a bright
+ side, it might allow to collect more data on dmesg like
+ stack traces from other CPUs or extra data dumped by
+ panic_print. This is usually only for users who doubt
+ kdump will succeed every time. 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
"Guilherme G. Piccoli" <gpiccoli@igalia.com> writes: > Be more clear about the downsides, the upsides (yes, there are some!) > and about code that unconditionally sets that. > > Signed-off-by: Guilherme G. Piccoli <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..cb25dc5cbe9a 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. As a bright > + side, it might allow to collect more data on dmesg like > + stack traces from other CPUs or extra data dumped by > + panic_print. This is usually only for users who doubt > + kdump will succeed every time. This is definitely clearer and an improvement! But I didn't (and still don't) love the phrase "users who doubt kdump will succeed" because I think that implies user error or silly beliefs. What if these two sentences read something like: In 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. Yes, great addition. With or without my suggestions it's an improvement, so: Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
On 30/08/2024 14:15, Stephen Brennan wrote: > [...] > > This is definitely clearer and an improvement! But I didn't (and still > don't) love the phrase "users who doubt kdump will succeed" because I > think that implies user error or silly beliefs. > > What if these two sentences read something like: > > In 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. > > Yes, great addition. > > With or without my suggestions it's an improvement, so: > > Reviewed-by: Stephen Brennan <stephen.s.brennan@oracle.com> > Thanks Stephen, I agree - your wording sounds better. I've incorporated that in the just sent V2. Cheers, Guilherme P.S. I'll be OOO some days, so expect a bit of delay in case there are more reviews/interactions.
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