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Date: Mon, 14 Dec 2009 13:22:41 +0100
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@elte.hu>,
       Wenji Huang <wenji.huang@oracle.com>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/4] tracing/filters: Fix MATCH_FRONT_ONLY filter
	matching
Message-ID: <20091214122239.GI5168@nowhere>
References: <4B2217D0.5000308@cn.fujitsu.com> <4B221800.1050504@cn.fujitsu.com> <20091211120218.GD5244@nowhere> <4B259849.6030205@cn.fujitsu.com>
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On Mon, Dec 14, 2009 at 09:43:37AM +0800, Li Zefan wrote:
> Frederic Weisbecker wrote:
> > On Fri, Dec 11, 2009 at 05:59:28PM +0800, Li Zefan wrote:
> >> MATCH_FRONT_ONLY matching works exactly as MATCH_FULL.
> >>
> >> We should pass the length of the pattern to strncmp().
> >>
> >> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
> >> ---
> >>  kernel/trace/trace_events_filter.c |    2 +-
> >>  1 files changed, 1 insertions(+), 1 deletions(-)
> >>
> >> diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
> >> index c8eb1c0..bd492ce 100644
> >> --- a/kernel/trace/trace_events_filter.c
> >> +++ b/kernel/trace/trace_events_filter.c
> >> @@ -262,7 +262,7 @@ static int regex_match_full(char *str, struct regex *r, int len)
> >>  
> >>  static int regex_match_front(char *str, struct regex *r, int len)
> >>  {
> >> -	if (strncmp(str, r->pattern, len) == 0)
> >> +	if (strncmp(str, r->pattern, r->len) == 0)
> >>  		return 1;
> >>  	return 0;
> >>  }
> > 
> > 
> > But it was working before the fix to match full.
> 
> No, it was not working for dyn_string and static_string.
> And as I explained it happened to work for ptr_string by
> the mixture of 2 bugs.


Ah, you're right.