Re: [PATCH -tip v3 00/23] kprobes: introduce NOKPROBE_SYMBOL() andgeneral cleaning of kprobe blacklist

[Steven Rostedt]

On Wed, 20 Nov 2013 12:36:00 -0500
"Frank Ch. Eigler" <fche@xxxxxxxxxx> wrote:

> Hi -
> 
> > > Does this new blacklist cover enough that the kernel now survives a 
> > > broadly wildcarded perf-probe, e.g. over e.g. all of its kallsyms?
> > 
> > That's generally the purpose of the annotations - if it doesn't then 
> > that's a bug.
> 
> AFAIK, no kernel since kprobes was introduced has ever stood up to
> that test.  perf probe lacks the wildcarding powers of systemtap, so
> one needs to resort to something like:
> 
> # cat /proc/kallsyms | grep ' [tT] ' | while read addr type symbol; do
>    perf probe $symbol
> done

I'm curious to why one would do that. IIUC, perf now has function
tracing support.

-- Steve

> 
> then wait for a few hours for that to finish. Then, or while the loop
> is still running, run
> 
> # perf record -e 'probe:*' -aR sleep 1
> 
> to take a kernel down.
> 
> 
> - FChE

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/