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authorSergey Senozhatsky <senozhatsky@chromium.org>2025-10-07 15:35:40 +0900
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2025-10-20 20:07:02 +0200
commita67818f74512452e9d99a98d990ea9d9b7c91791 (patch)
treefb410249880cef3bfd7375ec3e26db674912ac00
parent5a151c2328a78aa0949a393f5c475a64b93a89ca (diff)
PM: dpm_watchdog: add module param to backtrace all CPUs
Add dpm_watchdog_all_cpu_backtrace module parameter which controls all CPU backtrace dump before the DPM watchdog panics the system. This is expected to help understand what might have caused device timeout. Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reviewed-by: Tomasz Figa <tfiga@chromium.org> Reviewed-by: Dhruva Gole <d-gole@ti.com> Link: https://patch.msgid.link/20251007063551.3147937-1-senozhatsky@chromium.org [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/base/power/main.c10
1 files changed, 10 insertions, 0 deletions
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");
+
/**
* dpm_watchdog_handler - Driver suspend / resume watchdog handler.
* @t: The timer that PM watchdog depends on.
@@ -530,8 +536,12 @@ static void dpm_watchdog_handler(struct timer_list *t)
unsigned int time_left;
if (wd->fatal) {
+ unsigned int this_cpu = smp_processor_id();
+
dev_emerg(wd->dev, "**** DPM device timeout ****\n");
show_stack(wd->tsk, NULL, KERN_EMERG);
+ if (dpm_watchdog_all_cpu_backtrace)
+ trigger_allbutcpu_cpu_backtrace(this_cpu);
panic("%s %s: unrecoverable failure\n",
dev_driver_string(wd->dev), dev_name(wd->dev));
}