[PATCH] soc: ti: QMSS: Fix usage of irq_set_affinity_hint

Florian Fainelli
2018-10-30T17:02:25Z

On 10/30/18 4:11 AM, Marc Zyngier wrote:
> The Keystone QMSS driver is pretty damaged, in the sense that it
> does things like this:
>
> irq_set_affinity_hint(irq, to_cpumask(&cpu_map));
>
> where cpu_map is a local variable. As we leave the function, this
> will point to nowhere-land, and things will end-up badly.
>
> Instead, let's use a proper cpumask that gets allocated, giving
> the driver a chance to actually work with things like irqbalance
> as well as have a hypothetical 64bit future.

Since this is at least the second patch from you that I can see in this
area, would it make sense to sprinkle object_is_on_stack() checks
throughout irq_set_affinity_hint() to help catch offenders?

>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> I found this one by inspection after finding a similar bug in an
> unrelated driver. It is only compile-tested. It would probably
> a Cc stable, but that's Santosh's decision.
>
> drivers/soc/ti/knav_qmss.h | 4 ++--
> drivers/soc/ti/knav_qmss_acc.c | 10 +++++-----
> drivers/soc/ti/knav_qmss_queue.c | 22 +++++++++++++++-------
> 3 files changed, 22 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/soc/ti/knav_qmss.h b/drivers/soc/ti/knav_qmss.h
> index 3efc47e82973..bd040c29c4bf 100644
> --- a/drivers/soc/ti/knav_qmss.h
> +++ b/drivers/soc/ti/knav_qmss.h
> @@ -329,8 +329,8 @@ struct knav_range_ops {
> };
>
> struct knav_irq_info {
> - int irq;
> - u32 cpu_map;
> + int irq;
> + struct cpumask *cpu_mask;
> };
>
> struct knav_range_info {
> diff --git a/drivers/soc/ti/knav_qmss_acc.c b/drivers/soc/ti/knav_qmss_acc.c
> index 316e82e46f6c..2f7fb2dcc1d6 100644
> --- a/drivers/soc/ti/knav_qmss_acc.c
> +++ b/drivers/soc/ti/knav_qmss_acc.c
> @@ -205,18 +205,18 @@ static int knav_range_setup_acc_irq(struct knav_range_info *range,
> {
> struct knav_device *kdev = range->kdev;
> struct knav_acc_channel *acc;
> - unsigned long cpu_map;
> + struct cpumask *cpu_mask;
> int ret = 0, irq;
> u32 old, new;
>
> if (range->flags & RANGE_MULTI_QUEUE) {
> acc = range->acc;
> irq = range->irqs[0].irq;
> - cpu_map = range->irqs[0].cpu_map;
> + cpu_mask = range->irqs[0].cpu_mask;
> } else {
> acc = range->acc + queue;
> irq = range->irqs[queue].irq;
> - cpu_map = range->irqs[queue].cpu_map;
> + cpu_mask = range->irqs[queue].cpu_mask;
> }
>
> old = acc->open_mask;
> @@ -239,8 +239,8 @@ static int knav_range_setup_acc_irq(struct knav_range_info *range,
> acc->name, acc->name);
> ret = request_irq(irq, knav_acc_int_handler, 0, acc->name,
> range);
> - if (!ret && cpu_map) {
> - ret = irq_set_affinity_hint(irq, to_cpumask(&cpu_map));
> + if (!ret && cpu_mask) {
> + ret = irq_set_affinity_hint(irq, cpu_mask);
> if (ret) {
> dev_warn(range->kdev->dev,
> "Failed to set IRQ affinity\n");
> diff --git a/drivers/soc/ti/knav_qmss_queue.c b/drivers/soc/ti/knav_qmss_queue.c
> index b5d5673c255c..8b418379272d 100644
> --- a/drivers/soc/ti/knav_qmss_queue.c
> +++ b/drivers/soc/ti/knav_qmss_queue.c
> @@ -118,19 +118,17 @@ static int knav_queue_setup_irq(struct knav_range_info *range,
> struct knav_queue_inst *inst)
> {
> unsigned queue = inst->id - range->queue_base;
> - unsigned long cpu_map;
> int ret = 0, irq;
>
> if (range->flags & RANGE_HAS_IRQ) {
> irq = range->irqs[queue].irq;
> - cpu_map = range->irqs[queue].cpu_map;
> ret = request_irq(irq, knav_queue_int_handler, 0,
> inst->irq_name, inst);
> if (ret)
> return ret;
> disable_irq(irq);
> - if (cpu_map) {
> - ret = irq_set_affinity_hint(irq, to_cpumask(&cpu_map));
> + if (range->irqs[queue].cpu_mask) {
> + ret = irq_set_affinity_hint(irq, range->irqs[queue].cpu_mask);
> if (ret) {
> dev_warn(range->kdev->dev,
> "Failed to set IRQ affinity\n");
> @@ -1262,9 +1260,19 @@ static int knav_setup_queue_range(struct knav_device *kdev,
>
> range->num_irqs++;
>
> - if (IS_ENABLED(CONFIG_SMP) && oirq.args_count == 3)
> - range->irqs[i].cpu_map =
> - (oirq.args[2] & 0x0000ff00) >> 8;
> + if (IS_ENABLED(CONFIG_SMP) && oirq.args_count == 3) {
> + unsigned long mask;
> + int bit;
> +
> + range->irqs[i].cpu_mask = devm_kzalloc(dev,
> + cpumask_size(), GFP_KERNEL);
> + if (!range->irqs[i].cpu_mask)
> + return -ENOMEM;
> +
> + mask = (oirq.args[2] & 0x0000ff00) >> 8;
> + for_each_set_bit(bit, &mask, BITS_PER_LONG)
> + cpumask_set_cpu(bit, range->irqs[i].cpu_mask);
> + }
> }
>
> range->num_irqs = min(range->num_irqs, range->num_queues);
>

--
Florian