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Wysocki" , Pavel Machek Cc: Tomasz Figa , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: [RFC PATCH] PM: dpm: add module param to backtrace all CPUs Date: Wed, 23 Jul 2025 12:59:09 +0900 Message-ID: <20250723035955.486688-1-senozhatsky@chromium.org> X-Mailer: git-send-email 2.50.0.727.gbf7dc18ff4-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add dpm_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. Signed-off-by: Sergey Senozhatsky --- drivers/base/power/main.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index dbf5456cd891..9fb943afe246 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -34,6 +34,7 @@ #include #include #include +#include =20 #include "../base.h" #include "power.h" @@ -517,6 +518,9 @@ struct dpm_watchdog { #define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \ struct dpm_watchdog wd =20 +static bool __read_mostly dpm_all_cpu_backtrace; +module_param(dpm_all_cpu_backtrace, bool, 0644); + /** * dpm_watchdog_handler - Driver suspend / resume watchdog handler. * @t: The timer that PM watchdog depends on. @@ -532,8 +536,12 @@ static void dpm_watchdog_handler(struct timer_list *t) unsigned int time_left; =20 if (wd->fatal) { + unsigned int this_cpu =3D smp_processor_id(); + dev_emerg(wd->dev, "**** DPM device timeout ****\n"); show_stack(wd->tsk, NULL, KERN_EMERG); + if (dpm_all_cpu_backtrace) + trigger_single_cpu_backtrace(this_cpu); panic("%s %s: unrecoverable failure\n", dev_driver_string(wd->dev), dev_name(wd->dev)); } --=20 2.50.0.727.gbf7dc18ff4-goog