On 2022-08-12 02:20, Dan Carpenter wrote:
This code has two bugs. If kfd_topology_device_by_proximity_domain()
failed on the first iteration through the loop then "cpu_link" is
uninitialized and should not be dereferenced.
The second bug is that we cannot dereference a list iterator when it
points to the list head. In other words, if we exit the
list_for_each_entry() loop exits without hitting a break then "cpu_link"
is not a valid pointer and should not be dereferenced.
Fix both of these problems by setting "cpu_link" to NULL when it is invalid
and non-NULL when it is valid. That makes it easier to test for
valid vs invalid.
Fixes: 0f28cca87e9a ("drm/amdkfd: Extend KFD device topology to surface peer-to-peer links")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
I reported these in June but never heard back.
I thought Ramesh implemented a fix for this:
https://lore.kernel.org/all/20220706183302.1719795-1-Ramesh.Errabolu@xxxxxxx/
You commented on a version of his patch:
https://lore.kernel.org/all/20220629161241.GM11460@kadam/
Did this get lost somehow? Anyway, your patch looks good to me and I'm
going to apply it to amd-staging-drm-next now.
Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
Thanks,
Felix
drivers/gpu/drm/amd/amdkfd/kfd_topology.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
index 25990bec600d..3f0a4a415907 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
@@ -1392,8 +1392,8 @@ static int kfd_build_p2p_node_entry(struct kfd_topology_device *dev,
static int kfd_create_indirect_link_prop(struct kfd_topology_device *kdev, int gpu_node)
{
+ struct kfd_iolink_properties *gpu_link, *tmp_link, *cpu_link;
struct kfd_iolink_properties *props = NULL, *props2 = NULL;
- struct kfd_iolink_properties *gpu_link, *cpu_link;
struct kfd_topology_device *cpu_dev;
int ret = 0;
int i, num_cpu;
@@ -1416,16 +1416,19 @@ static int kfd_create_indirect_link_prop(struct kfd_topology_device *kdev, int g
continue;
/* find CPU <--> CPU links */
+ cpu_link = NULL;
cpu_dev = kfd_topology_device_by_proximity_domain(i);
if (cpu_dev) {
- list_for_each_entry(cpu_link,
+ list_for_each_entry(tmp_link,
&cpu_dev->io_link_props, list) {
- if (cpu_link->node_to == gpu_link->node_to)
+ if (tmp_link->node_to == gpu_link->node_to) {
+ cpu_link = tmp_link;
break;
+ }
}
}
- if (cpu_link->node_to != gpu_link->node_to)
+ if (!cpu_link)
return -ENOMEM;
/* CPU <--> CPU <--> GPU, GPU node*/
