1. 10 6月, 2019 1 次提交
    • S
      x86/ftrace: Do not call function graph from dynamic trampolines · 15c24a0f
      Steven Rostedt (VMware) 提交于
      [ Upstream commit d2a68c4effd821f0871d20368f76b609349c8a3b ]
      
      Since commit 79922b80 ("ftrace: Optimize function graph to be
      called directly"), dynamic trampolines should not be calling the
      function graph tracer at the end. If they do, it could cause the function
      graph tracer to trace functions that it filtered out.
      
      Right now it does not cause a problem because there's a test to check if
      the function graph tracer is attached to the same function as the
      function tracer, which for now is true. But the function graph tracer is
      undergoing changes that can make this no longer true which will cause
      the function graph tracer to trace other functions.
      
       For example:
      
       # cd /sys/kernel/tracing/
       # echo do_IRQ > set_ftrace_filter
       # mkdir instances/foo
       # echo ip_rcv > instances/foo/set_ftrace_filter
       # echo function_graph > current_tracer
       # echo function > instances/foo/current_tracer
      
      Would cause the function graph tracer to trace both do_IRQ and ip_rcv,
      if the current tests change.
      
      As the current tests prevent this from being a problem, this code does
      not need to be backported. But it does make the code cleaner.
      
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: x86@kernel.org
      Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
      Signed-off-by: NSasha Levin <sashal@kernel.org>
      Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
      Acked-by: NCaspar Zhang <caspar@linux.alibaba.com>
      15c24a0f
  2. 04 6月, 2019 39 次提交