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From: Andi Kleen <ak@linux.intel.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	acme@kernel.org, jolsa@kernel.org,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	eranian@google.com
Subject: Re: Support sample context in perf report
Date: Tue, 26 Feb 2019 14:55:20 -0800	[thread overview]
Message-ID: <87pnrerwh3.fsf@linux.intel.com> (raw)
In-Reply-To: <20190226223319.GA2393@krava> (Jiri Olsa's message of "Tue, 26 Feb 2019 23:33:19 +0100")

Jiri Olsa <jolsa@redhat.com> writes:
>
> im still getting compile error the new branch:
>
>   CC       ui/browsers/hists.o
> ui/browsers/hists.c: In function ‘perf_evsel__hists_browse’:
> ui/browsers/hists.c:2567:8: error: ‘%s’ directive output may be truncated writing up to 63 bytes into a region of size between 28 and 91 [-Werror=format-truncation=]
>    n += snprintf(script_opt + n, len - n, " --time %s,%s", start, end);
>         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> In file included from /usr/include/stdio.h:862,
>                  from ui/browsers/hists.c:5:
> /usr/include/bits/stdio2.h:64:10: note: ‘__builtin___snprintf_chk’ output between 10 and 136 bytes into a destination of size 100
>    return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
>           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>         __bos (__s), __fmt, __va_arg_pack ());
>         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
> mv: cannot stat 'ui/browsers/.hists.o.tmp': No such file or directory

I tested with gcc 8 and it built on a opensuse leap system.

Of course you never know where you end up with the gcc -Werror
russian roulette. I don't think any of those can really overflow,
it's all false positives. This one is particularly annoying
because the compiler seems to assume that every char[] variable
is filled up to the maximum, which is flat out wrong.

Anyways this patch should help.

-Andi

diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
index e35b274ee863..8ca988506388 100644
--- a/tools/perf/ui/browsers/hists.c
+++ b/tools/perf/ui/browsers/hists.c
@@ -2554,7 +2554,7 @@ do_run_script(struct hist_browser *browser __maybe_unused,
 	}
 
 	if (act->time) {
-		char start[64], end[64];
+		char start[22], end[22];
 		unsigned long starttime = act->time;
 		unsigned long endtime = act->time + symbol_conf.time_quantum;
 

  reply	other threads:[~2019-02-26 22:55 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-26  3:04 Support sample context in perf report Andi Kleen
2019-02-26  3:04 ` [PATCH v2 01/11] perf tools script: Support insn output for normal samples Andi Kleen
2019-02-26  3:04 ` [PATCH v2 02/11] perf tools report: Support nano seconds Andi Kleen
2019-02-26  3:04 ` [PATCH v2 03/11] perf tools report: Parse time quantum Andi Kleen
2019-02-26  3:04 ` [PATCH v2 04/11] perf tools report: Support time sort key Andi Kleen
2019-02-26  3:04 ` [PATCH v2 05/11] perf tools report: Use less for scripts output Andi Kleen
2019-02-26  3:04 ` [PATCH v2 06/11] perf tools report: Support running scripts for current time range Andi Kleen
2019-02-26  3:04 ` [PATCH v2 07/11] perf tools: Add perf_exe() helper to find perf binary Andi Kleen
2019-02-26  3:04 ` [PATCH v2 08/11] perf tools report: Support builtin perf script in scripts menu Andi Kleen
2019-02-26  3:04 ` [PATCH v2 09/11] perf tools: Add utility function to print ns time stamps Andi Kleen
2019-02-26  3:04 ` [PATCH v2 10/11] perf tools report: Implement browsing of individual samples Andi Kleen
2019-02-26  3:04 ` [PATCH v2 11/11] perf tools: Add some new tips describing the new options Andi Kleen
2019-02-26 22:33 ` Support sample context in perf report Jiri Olsa
2019-02-26 22:55   ` Andi Kleen [this message]
2019-02-27 11:18 ` Jiri Olsa
2019-02-27 16:01   ` Andi Kleen
2019-02-27 16:16     ` Jiri Olsa
2019-02-27 17:29       ` Andi Kleen
2019-02-27 17:41         ` Arnaldo Carvalho de Melo
2019-02-27 17:56           ` Jiri Olsa
  -- strict thread matches above, loose matches on Subject: below --
2019-03-11 14:44 Andi Kleen
2019-03-09  5:56 Andi Kleen
2019-03-05 14:47 Andi Kleen
2019-03-07 10:57 ` Jiri Olsa
2019-03-07 16:57   ` Andi Kleen
2019-02-28 18:35 Andi Kleen
2019-02-24 15:37 Andi Kleen

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