An issue was discovered in the Linux kernel through 4.17.2. The filter parsing in kernel/trace/trace_events_filter.c could be called with no filter, which is an N=0 case when it expected at least one line to have been read, thus making the N-1 index invalid. This allows attackers to cause a denial of service (slab out-of-bounds write) or possibly have unspecified other impact via crafted perf_event_open and mmap system calls.
https://github.com/torvalds/linux/commit/81f9c4e4177d31ced6f52a89bb70e93bfb77ca03
https://github.com/lcytxw/bug_repro/tree/master/bug_200019
https://bugzilla.kernel.org/show_bug.cgi?id=200019