Re: [PATCH 1/2] [BUGFIX] perf probe: Fix --list option to show events only with uprobe events

From: Masami Hiramatsu
Date: Wed Aug 13 2014 - 10:21:47 EST


(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@xxxxxxxxxxx


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