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Re: [PATCH tracing/kprobes v3 4/7] tracing/kprobes: Avoid field name confliction
- From: Frédéric Weisbecker <fweisbec at gmail dot com>
- To: Masami Hiramatsu <mhiramat at redhat dot com>
- Cc: Steven Rostedt <rostedt at goodmis dot org>, Ingo Molnar <mingo at elte dot hu>, lkml <linux-kernel at vger dot kernel dot org>, systemtap <systemtap at sources dot redhat dot com>, DLE <dle-develop at lists dot sourceforge dot net>, Thomas Gleixner <tglx at linutronix dot de>, Arnaldo Carvalho de Melo <acme at redhat dot com>, Mike Galbraith <efault at gmx dot de>, Paul Mackerras <paulus at samba dot org>, Peter Zijlstra <a dot p dot zijlstra at chello dot nl>, Christoph Hellwig <hch at infradead dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Jim Keniston <jkenisto at us dot ibm dot com>, "Frank Ch. Eigler" <fche at redhat dot com>
- Date: Mon, 12 Oct 2009 12:12:47 +0200
- Subject: Re: [PATCH tracing/kprobes v3 4/7] tracing/kprobes: Avoid field name confliction
- References: <20091007222733.1684.32035.stgit@dhcp-100-2-132.bos.redhat.com> <20091007222807.1684.26880.stgit@dhcp-100-2-132.bos.redhat.com> <c62985530910120310m386e9289v29e71fee1992476b@mail.gmail.com>
Le 12 octobre 2009 12:10, Frédéric Weisbecker <fweisbec@gmail.com> a écrit :
> 2009/10/8 Masami Hiramatsu <mhiramat@redhat.com>:
>> Check whether the argument name is conflict with other field names.
>>
>> Changes in v3:
>> ?- Check strcmp() == 0 instead of !strcmp().
>>
>> Changes in v2:
>> ?- Add common_lock_depth to reserved name list.
>>
>> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
>> Cc: Frederic Weisbecker <fweisbec@gmail.com>
>> Cc: Ingo Molnar <mingo@elte.hu>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
>> Cc: Steven Rostedt <rostedt@goodmis.org>
>> Cc: Mike Galbraith <efault@gmx.de>
>> Cc: Paul Mackerras <paulus@samba.org>
>> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
>> Cc: Christoph Hellwig <hch@infradead.org>
>> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
>> Cc: Jim Keniston <jkenisto@us.ibm.com>
>> Cc: Frank Ch. Eigler <fche@redhat.com>
>> ---
>>
>> ?kernel/trace/trace_kprobe.c | ? 65 +++++++++++++++++++++++++++++++++++--------
>> ?1 files changed, 53 insertions(+), 12 deletions(-)
>>
>> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
>> index 030f28c..e3b824a 100644
>> --- a/kernel/trace/trace_kprobe.c
>> +++ b/kernel/trace/trace_kprobe.c
>> @@ -38,6 +38,25 @@
>> ?#define MAX_EVENT_NAME_LEN 64
>> ?#define KPROBE_EVENT_SYSTEM "kprobes"
>>
>> +/* Reserved field names */
>> +#define FIELD_STRING_IP "ip"
>> +#define FIELD_STRING_NARGS "nargs"
>> +#define FIELD_STRING_RETIP "ret_ip"
>> +#define FIELD_STRING_FUNC "func"
>
>
> If it might conflict, then we should minimize the possibilities for
> that to happen.
>
> What if we prefix these fields with kprobed_ ?
>
> kprobed_ip
> kprobed_nargs
> kprobed_ret_ip
> kprobed_func
>
> We are lucky there in that kprobe functions in the kernel can't be kprobed
> so it's safe wrt the conflict in the same namespace.
>
> And we can further schrink the kprobed prefixes in userspace post processing.
>
> (If you agree with the above, that can be done incrementally).
>
> Thanks.
I'm an idiot. I should have looked at the 5/7 patch before sending this reply.
Just forget about what I said :-)