Re: [PATCH v3 5/9] powerpc: Use preempt_model_str().

[Shrikanth Hegde]

On 2/8/25 18:25, Christophe Leroy wrote:
> Le 08/02/2025 à 08:35, Shrikanth Hegde a écrit :
> > On 2/4/25 13:52, Sebastian Andrzej Siewior wrote:
> > > Use preempt_model_str() instead of manually conducting the preemption
> > > model. Use pr_emerg() instead of printk() to pass a loglevel.
> >
> > even on powerpc, i see __die ends up calling show_regs_print_info().
> > Why print it twice?
>
> I don't understand what you mean, what is printed twice ?
>
> I can't see show_regs_print_info() printing the preemption model, am I 
> missing something ?

Patch 2/9 add preemption string in dump_stack_print_info.

__die -> show_regs() _> show_regs_print_info() -> 
dump_stack_print_info() -> init_utsname()->version, preempt_model_str(), 
BUILD_ID_VAL);

Wont we end up in this path?

> Christophe
>
> > > Cc: Madhavan Srinivasan <maddy@xxxxxxxxxxxxx>
> > > Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> > > Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
> > > Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> > > Cc: Naveen N Rao <naveen@xxxxxxxxxx>
> > > Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
> > > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> > > ---
> > > v2…v3:
> > >    - Use printk() instead of pr_emerg() to remain consistent with the
> > >      other invocations in terms of printing context.
> > >
> > >   arch/powerpc/kernel/traps.c | 4 ++--
> > >   1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
> > > index edf5cabe5dfdb..d6d77d92b3358 100644
> > > --- a/arch/powerpc/kernel/traps.c
> > > +++ b/arch/powerpc/kernel/traps.c
> > > @@ -263,10 +263,10 @@ static int __die(const char *str, struct 
> > > pt_regs *regs, long err)
> > >   {
> > >       printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
> > > -    printk("%s PAGE_SIZE=%luK%s%s%s%s%s%s %s\n",
> > > +    printk("%s PAGE_SIZE=%luK%s %s %s%s%s%s %s\n",
> > >              IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? "LE" : "BE",
> > >              PAGE_SIZE / 1024, get_mmu_str(),
> > > -           IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "",
> > > +           preempt_model_str(),
> > >              IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
> > >              IS_ENABLED(CONFIG_SMP) ? (" NR_CPUS=" 
> > > __stringify(NR_CPUS)) : "",
> > >              debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",