[PATCH 3/7] tracing: Fix kernel crash while using empty filter with perf

From: Ravi Bangoria Kernel is crashing when user tries to record 'ftrace:function' event with empty filter: # perf record -e ftrace:function --filter="" ls # dmesg BUG: unable to handle kernel NULL pointer dereference at 0008 Oops: [#1] SMP

[PATCH 3/7] tracing: Fix kernel crash while using empty filter with perf

From: Ravi Bangoria Kernel is crashing when user tries to record 'ftrace:function' event with empty filter: # perf record -e ftrace:function --filter="" ls # dmesg BUG: unable to handle kernel NULL pointer dereference at 0008 Oops: [#1] SMP PTI ... RIP: