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

From: Frederic Weisbecker
Date: Mon Oct 12 2009 - 15:50:53 EST


On Mon, Oct 12, 2009 at 03:13:51PM -0400, Masami Hiramatsu wrote:
> Frederic Weisbecker wrote:
>> The conflict issue might not be obvious for a user desperately trying to set
>> a kprobe. Even for other failcases, it might not be obvious (blacklisted
>> symbols, syntax errors...)
>>
>> May be should you improve the error granularity and print a KERN_DEBUG
>> message?
>
> Agreed, and kprobes error handling should be improved too (in the most cases,
> it just returns -EINVAL).
>
> Thank you.
>


And btw, I'm enable to create a probe, neither through ftrace nor perf:

$ sudo ./perf probe -P 'p:sys_close sys_close $retval'
Adding new event: p:sys_close sys_close+0 $retval

Error: Failed to create event: Invalid argument


# echo 'p:sys_open sys_open $retval' > /debug/tracing/kprobe_events
bash: echo: write error : Invalid argument

I suspect I missed something very obvious with the syntax :)

I've applied your patches in:

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing.git
tracing/kprobes

Thanks.



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