In the Linux kernel, the following vulnerability has been resolved: af_unix: Fix task hung while purging oob_skb in GC. syzbot reported a task hung; at the same time, GC was looping infinitely in list_for_each_entry_safe() for OOB skb. [0] syzbot demonstrated that the list_for_each_entry_safe() was not actually safe in this case. A single skb could have references for multiple sockets. If we free such a skb in the list_for_each_entry_safe(), the current and next sockets could be unlinked in a single iteration. unix_notinflight() uses list_del_init() to unlink the socket, so the prefetched next socket forms a loop itself and list_for_each_entry_safe() never stops. Here, we must use while() and make sure we always fetch the first socket. [0]: Sending NMI from CPU 0 to CPUs 1: NMI ba