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Re: [PATCH -tip v8 19/26] kprobes: Show blacklist entries via debugfs
- From: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>
- To: Steven Rostedt <rostedt at goodmis dot org>
- Cc: linux-kernel at vger dot kernel dot org, Ingo Molnar <mingo at kernel dot org>, Andi Kleen <andi at firstfloor dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Sandeepa Prabhu <sandeepa dot prabhu at linaro dot org>, Frederic Weisbecker <fweisbec at gmail dot com>, x86 at kernel dot org, fche at redhat dot com, mingo at redhat dot com, systemtap at sourceware dot org, "H. Peter Anvin" <hpa at zytor dot com>, Thomas Gleixner <tglx at linutronix dot de>, "David S. Miller" <davem at davemloft dot net>
- Date: Tue, 25 Mar 2014 19:30:34 +0900
- Subject: Re: [PATCH -tip v8 19/26] kprobes: Show blacklist entries via debugfs
- Authentication-results: sourceware.org; auth=none
- References: <20140305115843 dot 22766 dot 8355 dot stgit at ltc230 dot yrl dot intra dot hitachi dot co dot jp> <20140305120056 dot 22766 dot 10704 dot stgit at ltc230 dot yrl dot intra dot hitachi dot co dot jp> <20140324161909 dot 5b8f854d at gandalf dot local dot home>
(2014/03/25 5:19), Steven Rostedt wrote:
> On Wed, 05 Mar 2014 21:00:56 +0900
> Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
>
>
>> kernel/kprobes.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++-------
>> 1 file changed, 53 insertions(+), 8 deletions(-)
>>
>> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
>> index a21b4e6..3214289 100644
>> --- a/kernel/kprobes.c
>> +++ b/kernel/kprobes.c
>> @@ -2249,6 +2249,46 @@ static const struct file_operations debugfs_kprobes_operations = {
>> .release = seq_release,
>> };
>>
>> +/* kprobes/blacklist -- shows which functions can not be probed */
>> +static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
>> +{
>> + return seq_list_start(&kprobe_blacklist, *pos);
>> +}
>> +
>> +static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
>> +{
>> + return seq_list_next(v, &kprobe_blacklist, pos);
>> +}
>> +
>
> Can modules use NOKPROBE_SYMBOL() and have items being added to the
> list as this is being read? That is, do we need locks?
At this point, no, the NOKPROBE_SYMBOL()s in module are just ignored.
> Also, are items removed. I need to go back and look at the
> implementation of NOKPROBE_SYMBOL(), I'm just writing this as I think
> about it ;-)
Actually, I've introduced a lock with module NOKPROBE_SYMBOL() support in
the next patch. :)
I'd like to split it because module blacklist support involves module
subsystem update.
Thank you!
--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com