CVE-2026-68332net: airoha: Fix potential use-after-free in airoha_ppe_deinit()

Official description

In the Linux kernel, the following vulnerability has been resolved: net: airoha: Fix potential use-after-free in airoha_ppe_deinit() airoha_ppe_deinit() replaces the NPU pointer with NULL via rcu_replace_pointer() but does not wait for existing RCU readers to exit before calling ppe_deinit() and airoha_npu_put(). This can cause a use-after-free if a reader in an RCU read-side critical section still holds a reference to the NPU when it is freed. The init path (airoha_ppe_init) already calls synchronize_rcu() after rcu_assign_pointer(), but the deinit path introduced in commit 6abcf751bc08 ("net: airoha: Fix schedule while atomic in airoha_ppe_deinit()") omitted the matching barrier when switching from rcu_read_lock()/rcu_dereference() to rcu_replace_pointer(). Add synchronize_rcu() before ppe_deinit() to ensure all existing RCU readers have completed before the NPU resources are released.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/46e3bed4b071095ecc9384a7b349e1908728531f
• https://git.kernel.org/stable/c/ad28c4f9e0eae4993cb3fde3e7cea330acd8b97c
• https://git.kernel.org/stable/c/2484568a335cd7bda951c75b3a7d95ea36161ae7