linux-kernel - Re: [PATCHv2] PM: dpm: add module param to backtrace all CPUs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251008130234.mw6k4k7fupxma2t5@lcpd911>
Date: Wed, 8 Oct 2025 18:32:34 +0530
From: Dhruva Gole <d-gole@...com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
CC: Sergey Senozhatsky <senozhatsky@...omium.org>,
        Pavel Machek
	<pavel@...nel.org>, Tomasz Figa <tfiga@...omium.org>,
        <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCHv2] PM: dpm: add module param to backtrace all CPUs

On Oct 08, 2025 at 13:23:33 +0200, Rafael J. Wysocki wrote:
> On Wed, Oct 8, 2025 at 12:14 PM Dhruva Gole <d-gole@...com> wrote:
> >
> > On Oct 07, 2025 at 15:35:40 +0900, Sergey Senozhatsky wrote:
> > > Add dpm_watchdog_all_cpu_backtrace module parameter which
> > > controls all CPU backtrace dump before DPM panics the system.
> > > This is expected to help understanding what might have caused
> > > device timeout.
> >
> > This will indeed be really helpful for debugging some nasty bugs!
> >
> > >
> > > Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
> > > ---
> > >  drivers/base/power/main.c | 10 ++++++++++
> > >  1 file changed, 10 insertions(+)
> > >
> > > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> > > index e83503bdc1fd..7a8807ec9a5d 100644
> > > --- a/drivers/base/power/main.c
> > > +++ b/drivers/base/power/main.c
> > > @@ -34,6 +34,7 @@
> > >  #include <linux/cpufreq.h>
> > >  #include <linux/devfreq.h>
> > >  #include <linux/timer.h>
> > > +#include <linux/nmi.h>
> > >
> > >  #include "../base.h"
> > >  #include "power.h"
> > > @@ -515,6 +516,11 @@ struct dpm_watchdog {
> > >  #define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \
> > >       struct dpm_watchdog wd
> > >
> > > +static bool __read_mostly dpm_watchdog_all_cpu_backtrace;
> > > +module_param(dpm_watchdog_all_cpu_backtrace, bool, 0644);
> > > +MODULE_PARM_DESC(dpm_watchdog_all_cpu_backtrace,
> > > +              "Backtrace all CPUs on DPM watchdog timeout");
> > > +
> >
> > Have you considered runtime configurability instead of a module param?
> 
> This one can be updated at run time AFAICS.

What I meant really was to consider another path instead of a mod param,
something like a /sys/kernel/ entry, but looking more into it I think this
is perfectly fine too.

Reviewed-by: Dhruva Gole <d-gole@...com>


-- 
Best regards,
Dhruva Gole
Texas Instruments Incorporated