CVE-2021-47559 net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk()

In the Linux kernel, the following vulnerability has been resolved: net/smc: Fix NULL pointer dereferencing in smcvlanbytcpsk Coverity reports a possible NULL dereferencing problem: in smcvlanbytcpsk: 6. returnednull: netdevlowergetnext returns NULL checked 29 out of 30 times. 7. varassigned:...