CVE-2021-47439

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net: dsa: microchip: Added the condition for scheduling ksz_mib_read_work<br /> <br /> When the ksz module is installed and removed using rmmod, kernel crashes<br /> with null pointer dereferrence error. During rmmod, ksz_switch_remove<br /> function tries to cancel the mib_read_workqueue using<br /> cancel_delayed_work_sync routine and unregister switch from dsa.<br /> <br /> During dsa_unregister_switch it calls ksz_mac_link_down, which in turn<br /> reschedules the workqueue since mib_interval is non-zero.<br /> Due to which queue executed after mib_interval and it tries to access<br /> dp-&gt;slave. But the slave is unregistered in the ksz_switch_remove<br /> function. Hence kernel crashes.<br /> <br /> To avoid this crash, before canceling the workqueue, resetted the<br /> mib_interval to 0.<br /> <br /> v1 -&gt; v2:<br /> -Removed the if condition in ksz_mib_read_work