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SubjectRe: [PATCH v2] drm/amdkfd: Fix potential NULL pointer dereferences

Quoting Oded Gabbay <oded.gabbay@gmail.com>:

> On Thu, Jan 11, 2018 at 1:15 AM, Gustavo A. R. Silva
> <garsilva@embeddedor.com> 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 printing a WARN_ON for PDDs that aren't found and skip
>> them with continue statements.
>>
>> Addresses-Coverity-ID: 1463794 ("Dereference null return value")
>> Addresses-Coverity-ID: 1463772 ("Dereference null return value")
>> Suggested-by: Felix Kuehling <felix.kuehling@amd.com>
>> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
>> ---
>> Changes in v2:
>> Print a WARN_ON and skip PDDs that aren't found instead of returning
>> an error.
>>
>> drivers/gpu/drm/amd/amdkfd/kfd_process.c | 8 +++++++-
>> 1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
>> b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
>> 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);
>> --
>> 2.7.4
>>
> This patch is:
> Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>

Thank you, Oded.
--
Gustavo




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