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WORKAROUND: ras: aest: Fix duplicate CPU PM notifier registration #1136

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Merged
Salendarsingh Gaud (sgaud-quic) merged 1 commit into from
Sep 19, 2026
+17 −0
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WORKAROUND: ras: aest: Fix duplicate CPU PM notifier registration #1136

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17 changes: 17 additions & 0 deletions drivers/ras/aest/aest-core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -110,14 +110,31 @@ static struct notifier_block aest_cpu_pm_nb = {
.notifier_call = aest_cpu_pm_notify,
};

/*
* platform_driver_register() walks matching devices synchronously in
* the calling thread (this driver does not opt into async probing, and
* aest_device_probe() never returns -EPROBE_DEFER), so repeated probes
* are strictly sequential, not concurrent -- a plain bool is sufficient
* and no additional locking is required here.
*/
static bool aest_cpu_pm_nb_registered;

@lumag Dmitry Baryshkov (lumag) Sep 19, 2026

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Why non of this has been sent upstream? Why do we need a global? where are the locks, protecting it from the read-modify happening at the same time? Device probing can happen in parallel.

@lumag Dmitry Baryshkov (lumag) Sep 19, 2026

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Even without async probing, the probe can happen in parallel if they are caused by other devices (e.g. if PCIe is built as a module).


static void aest_cpu_pm_init(void)
{
if (aest_cpu_pm_nb_registered)
return;

cpu_pm_register_notifier(&aest_cpu_pm_nb);
aest_cpu_pm_nb_registered = true;
}

static void aest_cpu_pm_exit(void)
{
if (!aest_cpu_pm_nb_registered)
return;

cpu_pm_unregister_notifier(&aest_cpu_pm_nb);
aest_cpu_pm_nb_registered = false;
}
#else
static inline void aest_cpu_pm_init(void) { }
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