Hi Felix,
Quoting Felix Kuehling felix.kuehling@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, 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@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);