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Re: [PATCH tracing/kprobes v3 4/7] tracing/kprobes: Avoid field name confliction
- From: Frederic 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 21:48:54 +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> <20091012173752.GB5059@nowhere> <4AD37FEF.9050807@redhat.com>
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.