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Re: [PATCH v3 2.6.39-rc1-tip 7/26] 7: x86: analyze instruction and determine fixups.
- From: Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>
- To: Steven Rostedt <rostedt at goodmis dot org>
- Cc: Peter Zijlstra <peterz at infradead dot org>, Ingo Molnar <mingo at elte dot hu>, Linux-mm <linux-mm at kvack dot org>, Arnaldo Carvalho de Melo <acme at infradead dot org>, Linus Torvalds <torvalds at linux-foundation dot org>, Andi Kleen <andi at firstfloor dot org>, Christoph Hellwig <hch at infradead dot org>, Jonathan Corbet <corbet at lwn dot net>, Thomas Gleixner <tglx at linutronix dot de>, Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>, Oleg Nesterov <oleg at redhat dot com>, LKML <linux-kernel at vger dot kernel dot org>, SystemTap <systemtap at sources dot redhat dot com>, Jim Keniston <jkenisto at linux dot vnet dot ibm dot com>, Roland McGrath <roland at hack dot frob dot com>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Andrew Morton <akpm at linux-foundation dot org>
- Date: Thu, 21 Apr 2011 23:01:20 +0530
- Subject: Re: [PATCH v3 2.6.39-rc1-tip 7/26] 7: x86: analyze instruction and determine fixups.
- References: <20110401143223.15455.19844.sendpatchset@localhost6.localdomain6> <20110401143348.15455.68644.sendpatchset@localhost6.localdomain6> <1303219751.7181.101.camel@gandalf.stny.rr.com>
- Reply-to: Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>
* Steven Rostedt <rostedt@goodmis.org> [2011-04-19 09:29:11]:
> On Fri, 2011-04-01 at 20:03 +0530, Srikar Dronamraju wrote:
>
> > +
> > +static void report_bad_prefix(void)
> > +{
> > + printk(KERN_ERR "uprobes does not currently support probing "
> > + "instructions with any of the following prefixes: "
> > + "cs:, ds:, es:, ss:, lock:\n");
> > +}
> > +
> > +static void report_bad_1byte_opcode(int mode, uprobe_opcode_t op)
> > +{
> > + printk(KERN_ERR "In %d-bit apps, "
> > + "uprobes does not currently support probing "
> > + "instructions whose first byte is 0x%2.2x\n", mode, op);
> > +}
> > +
> > +static void report_bad_2byte_opcode(uprobe_opcode_t op)
> > +{
> > + printk(KERN_ERR "uprobes does not currently support probing "
> > + "instructions with the 2-byte opcode 0x0f 0x%2.2x\n", op);
> > +}
>
> Should these really be KERN_ERR, or is KERN_WARNING a better fit?
>
> Also, can a non-privileged user cause these printks to spam the console
> and cause a DoS to the system?
>
Sometimes, the user might try registering a probe at a valid file +
valid offset + valid consumer; but an instruction that we cant probe.
Then trying to figure why its failing would be very hard.
how about pr_warn_ratelimited()?
--
Thanks and Regards
Srikar