Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933295Ab3DGKcT (ORCPT ); Sun, 7 Apr 2013 06:32:19 -0400 Received: from e7.ny.us.ibm.com ([32.97.182.137]:37517 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933217Ab3DGKcO (ORCPT ); Sun, 7 Apr 2013 06:32:14 -0400 Date: Sun, 7 Apr 2013 16:01:59 +0530 From: Srikar Dronamraju To: Oleg Nesterov Cc: Ananth N Mavinakayanahalli , Steven Rostedt , Anton Arapov , Frederic Weisbecker , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/6] uprobes/tracing: Make uprobe_{trace,perf}_print() uretprobe-friendly Message-ID: <20130407103159.GA6810@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20130401160827.GA19206@redhat.com> <20130401160851.GA19576@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20130401160851.GA19576@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13040710-5806-0000-0000-000020A1204D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4150 Lines: 127 * Oleg Nesterov [2013-04-01 18:08:51]: > Change uprobe_trace_print() and uprobe_perf_print() to check > is_ret_probe() and fill ring_buffer_event accordingly. > > Also change uprobe_trace_func() and uprobe_perf_func() to not > _print() if is_ret_probe() is true. Note that we keep ->handler() > nontrivial even for uretprobe, we need this for filtering and for > other potential extensions. > > Signed-off-by: Oleg Nesterov > --- > kernel/trace/trace_uprobe.c | 42 +++++++++++++++++++++++++++++++++--------- > 1 files changed, 33 insertions(+), 9 deletions(-) > > diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c > index e91a354..db2718a 100644 > --- a/kernel/trace/trace_uprobe.c > +++ b/kernel/trace/trace_uprobe.c > @@ -515,15 +515,26 @@ static void uprobe_trace_print(struct trace_uprobe *tu, > int size, i; > struct ftrace_event_call *call = &tu->call; > > - size = SIZEOF_TRACE_ENTRY(1) + tu->size; > + if (is_ret_probe(tu)) One nit: Here and couple of places below .. we could check for func instead of is_ret_probe() right? Or is there an advantage of checking is_ret_probe() over func? > + size = SIZEOF_TRACE_ENTRY(2); > + else > + size = SIZEOF_TRACE_ENTRY(1); > + > event = trace_current_buffer_lock_reserve(&buffer, call->event.type, > - size, 0, 0); > + size + tu->size, 0, 0); > if (!event) > return; > > entry = ring_buffer_event_data(event); > - entry->vaddr[0] = instruction_pointer(regs); > - data = DATAOF_TRACE_ENTRY(entry, 1); > + if (is_ret_probe(tu)) { > + entry->vaddr[0] = func; > + entry->vaddr[1] = instruction_pointer(regs); > + data = DATAOF_TRACE_ENTRY(entry, 2); > + } else { > + entry->vaddr[0] = instruction_pointer(regs); > + data = DATAOF_TRACE_ENTRY(entry, 1); > + } > + > for (i = 0; i < tu->nr_args; i++) > call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); > > @@ -534,7 +545,8 @@ static void uprobe_trace_print(struct trace_uprobe *tu, > /* uprobe handler */ > static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs) > { > - uprobe_trace_print(tu, 0, regs); > + if (!is_ret_probe(tu)) > + uprobe_trace_print(tu, 0, regs); Should this hunk be in the previous patch? Also something for the future: Most times a user uses a return probe, the user probably wants to probe the function entry too. So should we extend the abi from p+r to p+r+.. to mean it traces both function entry and return. Esp given that uretprobe has been elegantly been designed to make this a possibility. > return 0; > } > > @@ -783,7 +795,11 @@ static void uprobe_perf_print(struct trace_uprobe *tu, > void *data; > int size, rctx, i; > > - size = SIZEOF_TRACE_ENTRY(1); > + if (is_ret_probe(tu)) > + size = SIZEOF_TRACE_ENTRY(2); > + else > + size = SIZEOF_TRACE_ENTRY(1); > + > size = ALIGN(size + tu->size + sizeof(u32), sizeof(u64)) - sizeof(u32); > if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) > return; > @@ -794,8 +810,15 @@ static void uprobe_perf_print(struct trace_uprobe *tu, > goto out; > > ip = instruction_pointer(regs); > - entry->vaddr[0] = ip; > - data = DATAOF_TRACE_ENTRY(entry, 1); > + if (is_ret_probe(tu)) { > + entry->vaddr[0] = func; > + entry->vaddr[1] = ip; > + data = DATAOF_TRACE_ENTRY(entry, 2); > + } else { > + entry->vaddr[0] = ip; > + data = DATAOF_TRACE_ENTRY(entry, 1); > + } > + > for (i = 0; i < tu->nr_args; i++) > call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); > > @@ -811,7 +834,8 @@ static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs) > if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) > return UPROBE_HANDLER_REMOVE; > > - uprobe_perf_print(tu, 0, regs); > + if (!is_ret_probe(tu)) > + uprobe_perf_print(tu, 0, regs); > return 0; > } > > -- > 1.5.5.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/