In the Linux kernel, the following vulnerability has been resolved:
net: gtp: Fix Use-After-Free in gtp_dellink
Since callrcu, which is called in the hlistforeachentryrcu traversal of gtpdellink, is not part of the RCU read critical section, it is possible that the RCU grace period will pass during the traversal and the key will be free.
To prevent this, it should be changed to hlistforeachentrysafe.