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SubjectRe: [PATCH] tracing/profile: Fix profile_disable vs module_unload
> Peter is correct that he should not need to worry about modules, he 
> doesn't build kernels with them ;-)
>
> Here's another patch that moves the module ref count administration to the
> trace events themselves. This should satisfy both you and Peter.
>

In fact I had this patch in my mind, but I thought Peter insist
on fixing it in tracepoint. So I'm fine with this. :)

> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
>
> diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
> index 1b1f742..3f7c5dc 100644
> --- a/include/trace/ftrace.h
> +++ b/include/trace/ftrace.h
> @@ -390,6 +390,20 @@ static inline int ftrace_get_offsets_##call( \
> *
> */
>
> +#ifdef MODULE
> +# define event_trace_up_ref() \
> + do { \
> + if (!try_module_get(THIS_MODULE)) { \
> + atomic_dec(&event_call->profile_count); \
> + return -1; \

Should return -1 or -errno like -ENOENT?

> + } \
> + } while (0)
> +# define event_trace_down_ref() module_put(THIS_MODULE)
> +#else
> +# define event_trace_up_ref() do { } while (0)
> +# define event_trace_down_ref() do { } while (0)
> +#endif
> +
> #undef TRACE_EVENT
> #define TRACE_EVENT(call, proto, args, tstruct, assign, print) \
> \
> @@ -399,16 +413,20 @@ static int ftrace_profile_enable_##call(struct ftrace_event_call *event_call) \
> { \
> int ret = 0; \
> \
> - if (!atomic_inc_return(&event_call->profile_count)) \
> + if (!atomic_inc_return(&event_call->profile_count)) { \
> + event_trace_up_ref(); \
> ret = register_trace_##call(ftrace_profile_##call); \
> + } \
> \
> return ret; \
> } \
> \
> static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
> { \
> - if (atomic_add_negative(-1, &event_call->profile_count)) \
> + if (atomic_add_negative(-1, &event_call->profile_count)) { \
> unregister_trace_##call(ftrace_profile_##call); \
> + event_trace_down_ref(); \
> + } \
> }
>
> #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
>
>


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