6.12-stable review patch. If anyone has any objections, please let me know.
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From: Christian Loehle christian.loehle@arm.com
[ Upstream commit 1ebe8f7e782523e62cd1fa8237f7afba5d1dae83 ]
Commit e3f1164fc9ee ("PM: EM: Support late CPUs booting and capacity adjustment") added a mechanism to handle CPUs that come up late by retrying when any of the `cpufreq_cpu_get()` call fails.
However, if there are holes in the CPU topology (offline CPUs, e.g. nosmt), the first missing CPU causes the loop to break, preventing subsequent online CPUs from being updated.
Instead of aborting on the first missing CPU policy, loop through all and retry if any were missing.
Fixes: e3f1164fc9ee ("PM: EM: Support late CPUs booting and capacity adjustment") Suggested-by: Kenneth Crudup kenneth.crudup@gmail.com Reported-by: Kenneth Crudup kenneth.crudup@gmail.com Link: https://lore.kernel.org/linux-pm/40212796-734c-4140-8a85-854f72b8144d@panix.... Cc: 6.9+ stable@vger.kernel.org # 6.9+ Signed-off-by: Christian Loehle christian.loehle@arm.com Link: https://patch.msgid.link/20250831214357.2020076-1-christian.loehle@arm.com [ rjw: Drop the new pr_debug() message which is not very useful ] Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/power/energy_model.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
--- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -755,7 +755,7 @@ static void em_adjust_new_capacity(unsig static void em_check_capacity_update(void) { cpumask_var_t cpu_done_mask; - int cpu; + int cpu, failed_cpus = 0;
if (!zalloc_cpumask_var(&cpu_done_mask, GFP_KERNEL)) { pr_warn("no free memory\n"); @@ -773,10 +773,8 @@ static void em_check_capacity_update(voi
policy = cpufreq_cpu_get(cpu); if (!policy) { - pr_debug("Accessing cpu%d policy failed\n", cpu); - schedule_delayed_work(&em_update_work, - msecs_to_jiffies(1000)); - break; + failed_cpus++; + continue; } cpufreq_cpu_put(policy);
@@ -791,6 +789,9 @@ static void em_check_capacity_update(voi em_adjust_new_capacity(cpu, dev, pd); }
+ if (failed_cpus) + schedule_delayed_work(&em_update_work, msecs_to_jiffies(1000)); + free_cpumask_var(cpu_done_mask); }