From: masami.hiramatsu.pt@hitachi.com (Masami Hiramatsu) Date: Mon, 06 Jul 2015 20:37:49 +0900 Subject: [PATCH 1/2] arm64: Blacklist non-kprobe-able symbols In-Reply-To: <20150706090323.GB30342@arm.com> References: <9994841a0b0a8194a6dcc1b6af148ba358488c62.1436158027.git.panand@redhat.com> <20150706090323.GB30342@arm.com> Message-ID: <559A688D.1040501@hitachi.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 2015/07/06 18:03, Will Deacon wrote: > On Mon, Jul 06, 2015 at 06:03:21AM +0100, Pratyush Anand wrote: >> Add all function symbols which are called from do_debug_exception under >> NOKPROBE_SYMBOL, as they can not kprobed. > > It's a shame this has to be so manual, but I suppose it's done on a > best-effort basis to catch broken probe placement. Ah, yes. You can use kprobe-tracer in ftrace by feeding all symbols to them and enabling it (and pray). > If we miss a function and somebody probes it, do we just get stuck in a > recursive exception, or could we print something suggesting that a symbol > be annotated as NOKPROBE? For some cases we can detect recursion, but usually, it may reset itself or infinite recursion loop before detecting it. :( Thank you, -- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group E-mail: masami.hiramatsu.pt at hitachi.com