In the Linux kernel, the following vulnerability has been resolved:
ARM: 9064/1: hw_breakpoint: Do not directly check the events overflow_handler hook
The commit 1879445dfa7b (perf/core: Set events default ::overflow_handler()) set a default event->overflow_handler in perf_event_alloc(), and replace the check event->overflow_handler with is_default_overflow_handler(), but one is missing.
Currently, the bp->overflow_handler can not be NULL. As a result, enable_single_step() is always not invoked.
Comments from Zhen Lei: