[Devel] Re: [PATCH] event: fix TP_printk() argument in sched_switch

[Steven Rostedt]

On Thu, 2011-11-03 at 01:40 +0300, Andrew Vagin wrote:
> process_arg(...) can't parse "__entry->prev_state & (TASK_STATE_MAX-1)",
> because a complicated argument should be within brackets.

No it is fine, the userspace tool is broken.

> 
> Without this patch "perf report" prints following errors:
> $ ./perf record -ag -e sched:sched_switch
> ...
> $ ./perf report
>   Warning: Error: expected type 5 but read 4
>   Warning: Error: expected type 4 but read 0
>   Fatal: bad op token {
> 
> Signed-off-by: Andrew Vagin <avagin at openvz.org>

NACK!

This is a perf userspace bug, not a kernel one. Please fix the userspace
tool instead.

Note, the new version of libparsevent handles this case without issue.
Perf just needs to be updated.

-- Steve

> ---
>  include/trace/events/sched.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
> index 959ff18..1838237 100644
> --- a/include/trace/events/sched.h
> +++ b/include/trace/events/sched.h
> @@ -140,7 +140,7 @@ TRACE_EVENT(sched_switch,
>  	TP_printk("prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%s%s ==> next_comm=%s next_pid=%d next_prio=%d",
>  		__entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
>  		__entry->prev_state & (TASK_STATE_MAX-1) ?
> -		  __print_flags(__entry->prev_state & (TASK_STATE_MAX-1), "|",
> +		  __print_flags((__entry->prev_state & (TASK_STATE_MAX-1)), "|",
>  				{ 1, "S"} , { 2, "D" }, { 4, "T" }, { 8, "t" },
>  				{ 16, "Z" }, { 32, "X" }, { 64, "x" },
>  				{ 128, "W" }) : "R",