On 9/30/2025 10:29 PM, Przemek Kitszel wrote:
On 9/30/25 03:51, Haotian Zhang wrote:
quoted
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.
Release the reserved entry with xa_release() when adapter allocation
fails to prevent this issue.
Fixes: 0f0023c649c7 ("ice: do not init struct ice_adapter more times than needed")
Suggested-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Haotian Zhang <redacted>
---
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.
this is a correct improvement, but please let me propose other options,
with 2. being my favorite:
1. (just ice changes)
change the call order to be:
(note that it is under a mutex)
xa_load() // return early if another adapter exists
xa_reserve() // return early if no mem
ice_adapter_new() // return early if err
You still have to xa_release() here if we return early, but adding the
call to xa_reserve might be more expressive of the intended behavior vs
using xa_insert was.
xa_store()
2. (xarray changes)
(perhaps I'm biased as the one introducing the error on error path):
change xa_insert() to return 0 or -EEXIST when used as a reserving call
(IOW: caller wanted to reserve, entry is reserved, so return should be 0
(or -EEXIST if we really want to differentiate in the callers)).
If we go this route, I think -EEXIST is the right answer, as it should
only return 0 if *this* call reserved the entry. -EEXIST instead of
-EBUSY could differentiate between "slot is reserved" and "slot is
filled" though.
That would let us fix the issue by having xa_insert differentiate and go
ahead if it fines a reserved entry that was unused. Thats safe for *our*
use case because we know we were under lock and the only way we'd have a
stale reserved entry is if we failed to release it...
I am not certain how other users or maintainer of xarray would feel
about such a change, which makes me think the ice side change is the
best at least initially.
quoted
---
drivers/net/ethernet/intel/ice/ice_adapter.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_adapter.c b/drivers/net/ethernet/intel/ice/ice_adapter.c
index b53561c34708..9eb100b11439 100644
--- a/drivers/net/ethernet/intel/ice/ice_adapter.c
+++ b/drivers/net/ethernet/intel/ice/ice_adapter.c
@@ -110,8 +110,10 @@ struct ice_adapter *ice_adapter_get(struct pci_dev *pdev)
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;