linux-kernel - [PATCHv2 9/9] perf tools: Unwind properly location after REJECT

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Date:   Tue, 24 Oct 2017 14:51:21 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...nel.org>, lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        David Ahern <dsahern@...il.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Andi Kleen <andi@...stfloor.org>,
        "Jin, Yao" <yao.jin@...ux.intel.com>,
        "Wangnan (F)" <wangnan0@...wei.com>,
        "Du, Changbin" <changbin.du@...el.com>
Subject: [PATCHv2 9/9] perf tools: Unwind properly location after REJECT

On Fri, Oct 13, 2017 at 04:50:36PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Fri, Oct 13, 2017 at 10:37:36AM +0200, Jiri Olsa escreveu:
> > We have defined YY_USER_ACTION to keep trace of the column
> > location during events parsing, but we need to clean it up
> > when we call REJECT.
> > 
> > When REJECT is called, the lexer shrinks the text and re-runs
> > the matching, so we need to address it in resuming the previous
> > location value.
> 
> What is this fixing? Please state that, below I show what it is breaking
> :-/
> 
> Before:
> 
> [root@...et ~]# perf trace --no-syscalls -e ~acme/bpf/sys_read.c/max-stack=5/ sleep 1
> bpf: builtin compilation failed: -95, try external compiler
>      0.000 perf_bpf_probe:func:(ffffffffbb2634e0))
>                                        sys_read ([kernel.kallsyms])
>                                        entry_SYSCALL_64_fastpath ([kernel.kallsyms])
>                                        __read (/usr/lib64/ld-2.25.so)
>                                        _dl_map_object (/usr/lib64/ld-2.25.so)
> 
> After:
> 
> [root@...et ~]# perf trace --no-syscalls -e ~acme/bpf/sys_read.c/max-stack=5/ sleep 1
> event syntax error: '/home/acme/bpf/sys_read.c/max-stack=5/'
>                      \___ parser error
> Run 'perf list' for a list of valid events
> 
>  Usage: perf trace [<options>] [<command>]
>     or: perf trace [<options>] -- <command> [<options>]
>     or: perf trace record [<options>] [<command>]
>     or: perf trace record [<options>] -- <command> [<options>]
> 
>     -e, --event <event>   event/syscall selector. use 'perf list' to list available events
> [root@...et ~]# 
> 

v2 with updated changelog attached,

also I rebased the rest of the fixes and pushed
them into perf/fixes branch


thanks,
jirka


---
We have defined YY_USER_ACTION to keep trace of the column
location during events parsing, but we need to clean it up
when we call REJECT.

When REJECT is called, the lexer shrinks the text and re-runs
the matching, so we need to address it in resuming the previous
location value to keep it correct for error display, like:

Before:
  $ perf stat -e 'cpu/uops_executed.core,krava/'  true
  event syntax error: '..38;5;9:mi=01;05;37;41:su=48;5;196;38;5;15:sg=48;5;1\
1;38;5;16:ca=48;5;196;38;5;226:tw=48;5;10;38;5;16:ow=48;5;10;38;5;21:st=48;5;\
21;38;50
�'
                                  \___ unknown term

After:
  $ ./perf stat -e 'cpu/uops_executed.core,krava/'  true
  event syntax error: '..cuted.core,krava/'
                                    \___ unknown term

Tested-by: Andi Kleen <ak@...ux.intel.com>
Link: http://lkml.kernel.org/n/tip-vug2hchlny30jfsfrumbym26@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 tools/perf/util/parse-events.l | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 38a42bdf1492..241396cd059d 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -154,6 +154,10 @@ do {							\
 	yycolumn += yyleng;				\
 } while (0);
 
+#define USER_REJECT		\
+	yycolumn -= yyleng;	\
+	REJECT
+
 %}
 
 %x mem
@@ -336,8 +340,8 @@ r{num_raw_hex}		{ return raw(yyscanner); }
 {num_hex}		{ return value(yyscanner, 16); }
 
 {modifier_event}	{ return str(yyscanner, PE_MODIFIER_EVENT); }
-{bpf_object}		{ if (!isbpf(yyscanner)) REJECT; return str(yyscanner, PE_BPF_OBJECT); }
-{bpf_source}		{ if (!isbpf(yyscanner)) REJECT; return str(yyscanner, PE_BPF_SOURCE); }
+{bpf_object}		{ if (!isbpf(yyscanner)) USER_REJECT; return str(yyscanner, PE_BPF_OBJECT); }
+{bpf_source}		{ if (!isbpf(yyscanner)) USER_REJECT; return str(yyscanner, PE_BPF_SOURCE); }
 {name}			{ return pmu_str_check(yyscanner); }
 "/"			{ BEGIN(config); return '/'; }
 -			{ return '-'; }
-- 
2.13.6