Messages in this thread | | | Date | Sat, 26 Apr 2008 17:36:45 -0700 | From | Greg KH <> | Subject | Re: ftrace and debugfs weird interaction |
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On Sat, Apr 26, 2008 at 02:54:03PM -0400, Mathieu Desnoyers wrote: > Hi, > > When trying to figure out what was going on with the sched tracer > "tracing_enabled" file (sched-devel.git tree), I fell on this strange > behavior : > > echo 1>tracing_enabled seems _not_ to send 1 to the tracing_ctrl_write > callback. However, sending garbage, e.g. echo s> tracing_enabled, > correctly sends the 's' character down the chain. echo 0>tracing_enabled > sometimes results in the callback not even being called. > > The debugfs file has been created with > > entry = debugfs_create_file("tracing_enabled", 0644, d_tracer, > &global_trace, &tracing_ctrl_fops); > if (!entry) > pr_warning("Could not create debugfs 'tracing_enabled' entry\n"); > > I wonder what kind of weird debugfs interaction we might have here ?
I don't know. Are you sure your _fops is not getting called at all?
How about using a "default" operation for such a simple file, like debugfs_create_bool() as that is all you care about for this kind of value?
That should save you some code at the very least :)
thanks,
greg k-h
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