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Date: Wed, 13 Aug 2014 23:21:34 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Organization: Hitachi, Ltd., Japan
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To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>, Naohiro Aota <naota@elisp.net>,
        Ingo Molnar <mingo@redhat.com>, Paul Mackerras <paulus@samba.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] [BUGFIX] perf probe: Fix --list option to show events
 only with uprobe events
References: <20140813005055.24360.73553.stgit@kbuild-fedora.novalocal> <87r40ldkv8.fsf@sejong.aot.lge.com>
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(2014/08/13 14:22), Namhyung Kim wrote:
> Hi Masami,
> 
> On Wed, 13 Aug 2014 00:50:55 +0000, Masami Hiramatsu wrote:
>> +	if (kp_fd < 0 && up_fd < 0) {
>> +		/* Both kprobes and uprobes are disabled, warn it. */
>> +		if (kp_fd == -ENOTSUP && up_fd == -ENOTSUP)
>> +			pr_warning("Debugfs is not mounted.\n");
>> +		else if (kp_fd == -ENOENT && up_fd == -ENOENT)
>> +			pr_warning("Please rebuild kernel with "
>> +				   "CONFIG_KPROBE_EVENTS or/and "
>> +				   "CONFIG_UPROBE_EVENTS.\n");
>> +		else
>> +			pr_warning("Failed to open kprobe events: %s.\n" \
>> +				   "Failed to open uprobe events: %s.\n",
>> +				   strerror(-kp_fd), strerror(-up_fd));
> 
> It seems the second strerror() might overwrite the message of the
> first.  You'd better using strerror_r() IMHO.

Oops, right, it must use the same buffer...
But instead of using strerror_r, we can call pr_warning twice. Or should we
better replace all strerror to strerror_r in perf? (it should be another series)

Thank you,


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com