CVE-2024-39502CVE-2024-39502

In the Linux kernel, the following vulnerability has been resolved: ionic: fix use after netif_napi_del() When queues are started, netif_napi_add() and napi_enable() are called. If there are 4 queues and only 3 queues are used for the current configuration, only 3 queues' napi should be registered and enabled. The ionic_qcq_enable() checks whether the .poll pointer is not NULL for enabling only the using queue' napi. Unused queues' napi will not be registered by netif_napi_add(), so the .poll pointer indicates NULL. But it couldn't distinguish whether the napi was unregistered or not because netif_napi_del() doesn't reset the .poll pointer to NULL. So, ionic_qcq_enable() calls napi_enable() for the queue, which was unregistered by netif_napi_del(). Reproducer: ethtool -L <interface name> rx 1 tx 1 combined 0 ethtool -L <interface name> rx 0 tx 0 combined 1 ethtool -L <interface name> rx 0 tx 0 combined 4 Splat looks like: kernel BUG at net/core/dev.c:6666! Oops: invalid op