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September 2025

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[PATCH OLK-6.6] sdei_watchdog: add percpu flag to fix sdei watchdog state in lpi mode
by Bowen You 01 Sep '25

01 Sep '25

From: youbowen <youbowen2(a)huawei.com> hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8LQCC CVE: NA ------------------------------------------------- /proc/sys/kernel/nmi_watchdog interface is designed to close nmi watchdog, but currently, it's not working when in low power scenario, since pm callback will enable/disable event when power state changes. This commit add a percpu flag to be compatible with pm callback. Signed-off-by: Bowen You <youbowen2(a)huawei.com> --- arch/arm64/kernel/watchdog_sdei.c | 10 ++++++++-- include/linux/nmi.h | 1 + 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/watchdog_sdei.c b/arch/arm64/kernel/watchdog_sdei.c index 19f47e24fa59..13a9341bd5ca 100644 --- a/arch/arm64/kernel/watchdog_sdei.c +++ b/arch/arm64/kernel/watchdog_sdei.c @@ -25,6 +25,7 @@ static int sdei_watchdog_event_num; bool disable_sdei_nmi_watchdog; static bool sdei_watchdog_registered; static DEFINE_PER_CPU(ktime_t, last_check_time); +DEFINE_PER_CPU(bool, sdei_usr_en); void sdei_watchdog_hardlockup_enable(unsigned int cpu) { @@ -44,6 +45,7 @@ void sdei_watchdog_hardlockup_enable(unsigned int cpu) pr_err("Enable NMI Watchdog failed on cpu%d\n", smp_processor_id()); } + __this_cpu_write(sdei_usr_en, 1); } void sdei_watchdog_hardlockup_disable(unsigned int cpu) @@ -54,6 +56,7 @@ void sdei_watchdog_hardlockup_disable(unsigned int cpu) return; ret = sdei_api_event_disable(sdei_watchdog_event_num); + __this_cpu_write(sdei_usr_en, 0); if (ret) pr_err("Disable NMI Watchdog failed on cpu%d\n", smp_processor_id()); @@ -62,6 +65,7 @@ void sdei_watchdog_hardlockup_disable(unsigned int cpu) static int sdei_watchdog_callback(u32 event, struct pt_regs *regs, void *arg) { + pr_err("sdei watchdog callback on cpu %d\n", smp_processor_id()); ktime_t delta, now = ktime_get_mono_fast_ns(); delta = now - __this_cpu_read(last_check_time); @@ -116,10 +120,12 @@ static int sdei_watchdog_pm_notifier(struct notifier_block *nb, switch (action) { case CPU_PM_ENTER: - rv = sdei_api_event_disable(sdei_watchdog_event_num); + if (per_cpu(sdei_usr_en, smp_processor_id())) + rv = sdei_api_event_disable(sdei_watchdog_event_num); break; case CPU_PM_EXIT: - rv = sdei_api_event_enable(sdei_watchdog_event_num); + if (per_cpu(sdei_usr_en, smp_processor_id())) + rv = sdei_api_event_enable(sdei_watchdog_event_num); break; default: return NOTIFY_DONE; diff --git a/include/linux/nmi.h b/include/linux/nmi.h index 25fe091e1d19..0d32046d4b01 100644 --- a/include/linux/nmi.h +++ b/include/linux/nmi.h @@ -238,6 +238,7 @@ void sdei_watchdog_hardlockup_enable(unsigned int cpu); void sdei_watchdog_hardlockup_disable(unsigned int cpu); void sdei_watchdog_clear_eoi(void); int sdei_watchdog_hardlockup_probe(void); +DECLARE_PER_CPU(bool, sdei_usr_en); extern bool disable_sdei_nmi_watchdog; #else static inline void sdei_watchdog_hardlockup_enable(unsigned int cpu) { } -- 2.34.1

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