Pull more tracing fixes from Steven Rostedt:
 "Various tracing fixes:

   - Fix a crash when having function tracing and function stack tracing
     on the command line.

     The ftrace trampolines are created as executable and read only. But
     the stack tracer tries to modify them with text_poke() which
     expects all kernel text to still be writable at boot. Keep the
     trampolines writable at boot, and convert them to read-only with
     the rest of the kernel.

   - A selftest was triggering in the ring buffer iterator code, that is
     no longer valid with the update of keeping the ring buffer writable
     while a iterator is reading.

     Just bail after three failed attempts to get an event and remove
     the warning and disabling of the ring buffer.

   - While modifying the ring buffer code, decided to remove all the
     unnecessary BUG() calls"

* tag 'trace-v5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ring-buffer: Remove all BUG() calls
  ring-buffer: Don't deactivate the ring buffer on failed iterator reads
  x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up