tree a512491bd070579650776fdb28eb766df1b8b25d
parent d5ff0814fda50f0306e102f39640cf5bb76af08e
parent 82cc4fc2e70ec5baeff8f776f2773abc8b2cc0ae
author Linus Torvalds <torvalds@linux-foundation.org> 1492362094 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1492362094 -0700
mergetag object 82cc4fc2e70ec5baeff8f776f2773abc8b2cc0ae
 type commit
 tag trace-v4.11-rc5-2
 tagger Steven Rostedt <rostedt@goodmis.org> 1492290329 -0400
 
 While rewriting the function probe code, I stumbled over a long standing
 bug. This bug has been there sinc function tracing was added way back
 when. But my new development depends on this bug being fixed, and it
 should be fixed regardless as it causes ftrace to disable itself when
 triggered, and a reboot is required to enable it again.
 
 The bug is that the function probe does not disable itself properly
 if there's another probe of its type still enabled. For example:
 
      # cd /sys/kernel/debug/tracing
      # echo schedule:traceoff > set_ftrace_filter
      # echo do_IRQ:traceoff > set_ftrace_filter
      # echo \!do_IRQ:traceoff > /debug/tracing/set_ftrace_filter
      # echo do_IRQ:traceoff > set_ftrace_filter
 
 The above registers two traceoff probes (one for schedule and one for
 do_IRQ, and then removes do_IRQ. But since there still exists one for
 schedule, it is not done properly. When adding do_IRQ back, the breakage
 in the accounting is noticed by the ftrace self tests, and it causes
 a warning and disables ftrace.
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Merge tag 'trace-v4.11-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull ftrace fix from Steven Rostedt:
 "While rewriting the function probe code, I stumbled over a long
  standing bug. This bug has been there sinc function tracing was added
  way back when. But my new development depends on this bug being fixed,
  and it should be fixed regardless as it causes ftrace to disable
  itself when triggered, and a reboot is required to enable it again.

  The bug is that the function probe does not disable itself properly if
  there's another probe of its type still enabled. For example:

     # cd /sys/kernel/debug/tracing
     # echo schedule:traceoff > set_ftrace_filter
     # echo do_IRQ:traceoff > set_ftrace_filter
     # echo \!do_IRQ:traceoff > /debug/tracing/set_ftrace_filter
     # echo do_IRQ:traceoff > set_ftrace_filter

  The above registers two traceoff probes (one for schedule and one for
  do_IRQ, and then removes do_IRQ.

  But since there still exists one for schedule, it is not done
  properly. When adding do_IRQ back, the breakage in the accounting is
  noticed by the ftrace self tests, and it causes a warning and disables
  ftrace"

* tag 'trace-v4.11-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix removing of second function probe