Hi Felix,
Quoting Felix Kuehling <felix.kuehling at amd.com>:
> Hi Gustavo,
>
> Thanks for catching that. When returning a fault, I think you also need
> to srcu_read_unlock(&kfd_processes_srcu, idx).
>
> However, instead of returning an error, I think I'd prefer to skip PDDs
> that can't be found with continue statements. That way others would
> still suspend and resume successfully. Maybe just print a WARN_ON for
> PDDs that aren't found, because that's an unexpected situation,
> currently. Maybe in the future it could be normal thing if we ever
> support GPU hotplug.
>
I got it. In that case, what do you think about the following patch instead?
index a22fb071..4ff5f0f 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -461,7 +461,8 @@ int kfd_bind_processes_to_device(struct kfd_dev *dev)
hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
mutex_lock(&p->mutex);
pdd = kfd_get_process_device_data(dev, p);
- if (pdd->bound != PDD_BOUND_SUSPENDED) {
+
+ if (WARN_ON(!pdd) || pdd->bound != PDD_BOUND_SUSPENDED) {
mutex_unlock(&p->mutex);
continue;
}
@@ -501,6 +502,11 @@ void kfd_unbind_processes_from_device(struct
kfd_dev *dev)
mutex_lock(&p->mutex);
pdd = kfd_get_process_device_data(dev, p);
+ if (WARN_ON(!pdd)) {
+ mutex_unlock(&p->mutex);
+ continue;
+ }
+
if (pdd->bound == PDD_BOUND)
pdd->bound = PDD_BOUND_SUSPENDED;
mutex_unlock(&p->mutex);
Thank you for the feedback.
--
Gustavo
> Regards,
> Â Felix
>
>
> On 2018-01-10 11:50 AM, Gustavo A. R. Silva wrote:
>> In case kfd_get_process_device_data returns null, there are some
>> null pointer dereferences in functions kfd_bind_processes_to_device
>> and kfd_unbind_processes_from_device.
>>
>> Fix this by null checking pdd before dereferencing it.
>>
>> Addresses-Coverity-ID: 1463794 ("Dereference null return value")
>> Addresses-Coverity-ID: 1463772 ("Dereference null return value")
>> Signed-off-by: Gustavo A. R. Silva <garsilva at embeddedor.com>
>> ---
>> drivers/gpu/drm/amd/amdkfd/kfd_process.c | 12 ++++++++++++
>> 1 file changed, 12 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
>> b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
>> index a22fb071..29d51d5 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
>> @@ -461,6 +461,13 @@ int kfd_bind_processes_to_device(struct kfd_dev *dev)
>> hash_for_each_rcu(kfd_processes_table, temp, p, kfd_processes) {
>> mutex_lock(&p->mutex);
>> pdd = kfd_get_process_device_data(dev, p);
>> +
>> + if (!pdd) {
>> + pr_err("Process device data doesn't exist\n");
>> + mutex_unlock(&p->mutex);
>> + return -EFAULT;
>> + }
>> +
>> if (pdd->bound != PDD_BOUND_SUSPENDED) {
>> mutex_unlock(&p->mutex);
>> continue;
>> @@ -501,6 +508,11 @@ void kfd_unbind_processes_from_device(struct
>> kfd_dev *dev)
>> mutex_lock(&p->mutex);
>> pdd = kfd_get_process_device_data(dev, p);
>>
>> + if (!pdd) {
>> + mutex_unlock(&p->mutex);
>> + return;
>> + }
>> +
>> if (pdd->bound == PDD_BOUND)
>> pdd->bound = PDD_BOUND_SUSPENDED;
>> mutex_unlock(&p->mutex);
