This is a note to let you know that I've just added the patch titled

bus: arm-cci: Fix use of smp_processor_id() in preemptible context

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: bus-arm-cci-fix-use-of-smp_processor_id-in-preemptible-context.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 4608af8aa53e7f3922ddee695d023b7bcd5cb35b Mon Sep 17 00:00:00 2001

From: Marc Zyngier marc.zyngier@arm.com Date: Tue, 3 Oct 2017 18:14:13 +0100 Subject: bus: arm-cci: Fix use of smp_processor_id() in preemptible context

From: Marc Zyngier marc.zyngier@arm.com

commit 4608af8aa53e7f3922ddee695d023b7bcd5cb35b upstream.

The ARM CCI driver seem to be using smp_processor_id() in a preemptible context, which is likely to make a DEBUG_PREMPT kernel scream at boot time.

Turn this into a get_cpu()/put_cpu() that extends over the CPU hotplug registration, making sure that we don't race against a CPU down operation.

Signed-off-by: Marc Zyngier marc.zyngier@arm.com Acked-by: Mark Rutland mark.rutland@arm.com Signed-off-by: Pawel Moll pawel.moll@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/bus/arm-cci.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/bus/arm-cci.c +++ b/drivers/bus/arm-cci.c @@ -1755,14 +1755,17 @@ static int cci_pmu_probe(struct platform raw_spin_lock_init(&cci_pmu->hw_events.pmu_lock); mutex_init(&cci_pmu->reserve_mutex); atomic_set(&cci_pmu->active_events, 0); - cpumask_set_cpu(smp_processor_id(), &cci_pmu->cpus); + cpumask_set_cpu(get_cpu(), &cci_pmu->cpus);

ret = cci_pmu_init(cci_pmu, pdev); - if (ret) + if (ret) { + put_cpu(); return ret; + }

cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_CCI_ONLINE, &cci_pmu->node); + put_cpu(); pr_info("ARM %s PMU driver probed", cci_pmu->model->name); return 0; }

Patches currently in stable-queue which might be from marc.zyngier@arm.com are

queue-4.14/arm-kvm-fix-vttbr_baddr_mask-bug_on-off-by-one.patch queue-4.14/kvm-arm-arm64-vgic-its-check-result-of-allocation-before-use.patch queue-4.14/kvm-arm-arm64-vgic-preserve-the-revious-read-from-the-pending-table.patch queue-4.14/kvm-arm-arm64-vgic-irqfd-fix-msi-entry-allocation.patch queue-4.14/bus-arm-cci-fix-use-of-smp_processor_id-in-preemptible-context.patch queue-4.14/arm64-kvm-fix-vttbr_baddr_mask-bug_on-off-by-one.patch queue-4.14/bus-arm-ccn-fix-use-of-smp_processor_id-in-preemptible-context.patch