Re: [PATCH] lib tools traceevent: Add back pevent assignment in __pevent_parse_format()

[Namhyung Kim <namhyung@kernel.org>]

2012-09-28 (금), 22:20 -0400, Steven Rostedt:
> Even though with the change of commit commit 2b29175 "tools lib traceevent:
> Carve out events format parsing routine", allowed __pevent_parse_format() to
> parse an event without the need of a pevent handler, the event still needs to
> assign the pevent handed to it.
> 
> There's no problem with assigning it if the pevent is NULL, as the event->pevent
> would be NULL without the assignment. But function parsing handlers may be
> assigned to the pevent handler to help in parsing the event. If there's no
> pevent then there would not be any function handlers, but if the pevent
> isn't assigned first before parsing the event, it wont honor the function
> handlers that were assigned.
> 
> Worse yet, the current code crashes if an event has a function that it tries
> to parse. For example:
> 
>  # perf record -e scsi:scsi_dispatch_cmd_timeout
>  Segmentation fault (core dumped)
> 
> This happens because the scsi_dispatch_cmd_timeout event format has the following:
> 
>   __print_hex(__get_dynamic_array(cmnd), REC->cmd_len)
> 
> which hasn't been defined by the pevent code.

???  We have both of __print_hex() and __get_dynamic_array() handler,
please see process_function.  In my case, the offending function was
"scsi_trace_parse_cdb".

Other than that, looks good to me.

Reviewed-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung