When ice_adapter_new() fails, the reserved XArray entry created by
xa_insert() is not released. This causes subsequent insertions at
the same index to return -EBUSY, potentially leading to
NULL pointer dereferences.
Reorder the operations as suggested by Przemek Kitszel:
1. Check if adapter already exists (xa_load)
2. Reserve the XArray slot (xa_reserve)
3. Allocate the adapter (ice_adapter_new)
4. Store the adapter (xa_store)
Fixes: 0f0023c649c7 ("ice: do not init struct ice_adapter more times than
needed")
Suggested-by: Przemek Kitszel <[email protected]>
Suggested-by: Jacob Keller <[email protected]>
Signed-off-by: Haotian Zhang <[email protected]>
---
Changes in v3:
- Reorder xa_load/xa_reserve/ice_adapter_new/xa_store calls as
suggested by Przemek Kitszel, instead of just adding xa_release().
Changes in v2:
- Instead of checking the return value of xa_store(), fix the real bug
where a failed ice_adapter_new() would leave a stale entry in the
XArray.
- Use xa_release() to clean up the reserved entry, as suggested by
Jacob Keller.
---
drivers/net/ethernet/intel/ice/ice_adapter.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_adapter.c
b/drivers/net/ethernet/intel/ice/ice_adapter.c
index b53561c34708..0a8a48cd4bce 100644
--- a/drivers/net/ethernet/intel/ice/ice_adapter.c
+++ b/drivers/net/ethernet/intel/ice/ice_adapter.c
@@ -99,19 +99,21 @@ struct ice_adapter *ice_adapter_get(struct pci_dev *pdev)
index = ice_adapter_xa_index(pdev);
scoped_guard(mutex, &ice_adapters_mutex) {
- err = xa_insert(&ice_adapters, index, NULL, GFP_KERNEL);
- if (err == -EBUSY) {
- adapter = xa_load(&ice_adapters, index);
+ adapter = xa_load(&ice_adapters, index);
+ if (adapter) {
refcount_inc(&adapter->refcount);
WARN_ON_ONCE(adapter->index != ice_adapter_index(pdev));
return adapter;
}
+ err = xa_reserve(&ice_adapters, index, GFP_KERNEL);
if (err)
return ERR_PTR(err);
adapter = ice_adapter_new(pdev);
- if (!adapter)
+ if (!adapter) {
+ xa_release(&ice_adapters, index);
return ERR_PTR(-ENOMEM);
+ }
xa_store(&ice_adapters, index, adapter, GFP_KERNEL);
}
return adapter;
--
2.50.1.windows.1
