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From: Josh Poimboeuf <>
To: Laura Abbott <>
Cc: Arnaldo Carvalho de Melo <>,
	Adrian Hunter <>,
	Jiri Olsa <>, Namhyung Kim <>,
	Wang Nan <>,
	Linux Kernel Mailing List <>
Subject: Re: New -Werror=restrict error with incremental gcc
Date: Thu, 15 Mar 2018 22:11:54 -0500
Message-ID: <20180316031154.juk2uncs7baffctp@treble> (raw)
In-Reply-To: <>

On Thu, Mar 15, 2018 at 08:06:26AM -0700, Laura Abbott wrote:
> This only showed up with the very latest rawhide snapshot, .17 worked and
> .18 started failing. I had to download .18 manually to test locally

I also see the error with the latest gcc master branch.  The code is
harmless, but maybe the warning is useful in other places, so here's one
way to fix it.


From: Josh Poimboeuf <>
Subject: [PATCH] objtool, perf: Fix GCC 8 -Wrestrict error

Starting with recent GCC 8 builds, objtool and perf fail to build with
the following error:

  ../str_error_r.c: In function ‘str_error_r’:
  ../str_error_r.c:25:3: error: passing argument 1 to restrict-qualified parameter aliases with argument 5 [-Werror=restrict]
     snprintf(buf, buflen, "INTERNAL ERROR: strerror_r(%d, %p, %zd)=%d", errnum, buf, buflen, err);

The code seems harmless, but there's probably no benefit in printing the
'buf' pointer in this situation anyway, so just remove it to make GCC

Signed-off-by: Josh Poimboeuf <>
 tools/lib/str_error_r.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/lib/str_error_r.c b/tools/lib/str_error_r.c
index d6d65537b0d9..6aad8308a0ac 100644
--- a/tools/lib/str_error_r.c
+++ b/tools/lib/str_error_r.c
@@ -22,6 +22,6 @@ char *str_error_r(int errnum, char *buf, size_t buflen)
 	int err = strerror_r(errnum, buf, buflen);
 	if (err)
-		snprintf(buf, buflen, "INTERNAL ERROR: strerror_r(%d, %p, %zd)=%d", errnum, buf, buflen, err);
+		snprintf(buf, buflen, "INTERNAL ERROR: strerror_r(%d, [buf], %zd)=%d", errnum, buflen, err);
 	return buf;

  reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-14 21:19 Laura Abbott
2018-03-15 12:50 ` Jiri Olsa
2018-03-15 14:30 ` Arnaldo Carvalho de Melo
2018-03-15 15:06   ` Laura Abbott
2018-03-16  3:11     ` Josh Poimboeuf [this message]
2018-03-17  0:56       ` Laura Abbott
2018-03-20  6:36       ` [tip:perf/core] objtool, perf: Fix GCC 8 -Wrestrict error tip-bot for Josh Poimboeuf

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