ravb: Fix use-after-free issue in ravb_tx_timeout_work()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: ravb: Fix use-after-free issue in ravb_tx_timeout_work() The ravb_stop() should call cancel_work_sync(). Otherwise, ravb_tx_timeout_work() is possible to use the freed priv after ravb_remove() was called like below: CPU0 CPU1 ravb_tx_timeout() ravb_remove() unregister_netdev() free_netdev(ndev) // free priv ravb_tx_timeout_work() // use priv unregister_netdev() will call .ndo_stop() so that ravb_stop() is called. And, after phy_stop() is called, netif_carrier_off() is also called. So that .ndo_tx_timeout() will not be called after phy_stop().

References

• https://git.kernel.org/stable/c/65d34cfd4e347054eb4193bc95d9da7eaa72dee5
• https://git.kernel.org/stable/c/db9aafa19547833240f58c2998aed7baf414dc82
• https://git.kernel.org/stable/c/616761cf9df9af838c0a1a1232a69322a9eb67e6
• https://git.kernel.org/stable/c/6f6fa8061f756aedb93af12a8a5d3cf659127965
• https://git.kernel.org/stable/c/105abd68ad8f781985113aee2e92e0702b133705
• https://git.kernel.org/stable/c/3971442870713de527684398416970cf025b4f89