Re: [PATCH tracing/kprobes v3 4/7] tracing/kprobes: Avoid field name confliction

[Frédéric Weisbecker]

Le 12 octobre 2009 12:10, Frédéric Weisbecker <fweisbec@xxxxxxxxx> a écrit :
> 2009/10/8 Masami Hiramatsu <mhiramat@xxxxxxxxxx>:
>> 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@xxxxxxxxxx>
>> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
>> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
>> Cc: Mike Galbraith <efault@xxxxxx>
>> Cc: Paul Mackerras <paulus@xxxxxxxxx>
>> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
>> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
>> Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
>> Cc: Jim Keniston <jkenisto@xxxxxxxxxx>
>> Cc: Frank Ch. Eigler <fche@xxxxxxxxxx>
>> ---
>>
>>  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 :-)
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