• Namhyung Kim's avatar
    function_graph: Handle TRACE_BPUTS in print_graph_comment · 613dccdf
    Namhyung Kim authored
    It missed to handle TRACE_BPUTS so messages recorded by trace_bputs()
    will be shown with symbol info unnecessarily.
    
    You can see it with the trace_printk sample code:
    
      # cd /sys/kernel/tracing/
      # echo sys_sync > set_graph_function
      # echo 1 > options/sym-offset
      # echo function_graph > current_tracer
    
    Note that the sys_sync filter was there to prevent recording other
    functions and the sym-offset option was needed since the first message
    was called from a module init function so kallsyms doesn't have the
    symbol and omitted in the output.
    
      # cd ~/build/kernel
      # insmod samples/trace_printk/trace-printk.ko
    
      # cd -
      # head trace
    
    Before:
    
      # tracer: function_graph
      #
      # CPU  DURATION                  FUNCTION CALLS
      # |     |   |                     |   |   |   |
       1)               |  /* 0xffffffffa0002000: This is a static string that will use trace_bputs */
       1)               |  /* This is a dynamic string that will use trace_puts */
       1)               |  /* trace_printk_irq_work+0x5/0x7b [trace_printk]: (irq) This is a static string that will use trace_bputs */
       1)               |  /* (irq) This is a dynamic string that will use trace_puts */
       1)               |  /* (irq) This is a static string that will use trace_bprintk() */
       1)               |  /* (irq) This is a dynamic string that will use trace_printk */
    
    After:
    
      # tracer: function_graph
      #
      # CPU  DURATION                  FUNCTION CALLS
      # |     |   |                     |   |   |   |
       1)               |  /* This is a static string that will use trace_bputs */
       1)               |  /* This is a dynamic string that will use trace_puts */
       1)               |  /* (irq) This is a static string that will use trace_bputs */
       1)               |  /* (irq) This is a dynamic string that will use trace_puts */
       1)               |  /* (irq) This is a static string that will use trace_bprintk() */
       1)               |  /* (irq) This is a dynamic string that will use trace_printk */
    
    Link: http://lkml.kernel.org/r/20160901024354.13720-1-namhyung@kernel.orgSigned-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
    Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
    613dccdf
trace_functions_graph.c 36.4 KB