CVE-2026-90113
Description
In the Linux kernel, the following vulnerability has been resolved:
netdevsim: update queue NAPI association on queue reset
In netdevsim, receive queues (struct nsim_rq) embed their own struct
napi_struct. When queue reset is performed (e.g. via queue_reset
debugfs), nsim_queue_start() swaps in a newly allocated struct nsim_rq,
and nsim_queue_mem_free() later deletes and frees the old one.
However, nsim_queue_start() failed to update the queue-to-NAPI mapping
via netif_queue_set_napi(). As a result, dev->_rx[idx].napi continued to
point to the old NAPI struct. After the old queue was freed, a subsequent
queue dump via Netlink (NETDEV_CMD_QUEUE_GET) triggered a KASAN
slab-use-after-free read in nla_put_napi_id() when accessing
rxq->napi->napi_id.
Fix this by calling netif_queue_set_napi() in nsim_queue_start() to
associate the new NAPI with the RX queue, and clear the association
with netif_queue_set_napi(..., NULL) in nsim_del_napi() during teardown.