Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752698AbcDZIjq (ORCPT ); Tue, 26 Apr 2016 04:39:46 -0400 Received: from e23smtp06.au.ibm.com ([202.81.31.148]:59548 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752453AbcDZIji (ORCPT ); Tue, 26 Apr 2016 04:39:38 -0400 X-IBM-Helo: d23dlp03.au.ibm.com X-IBM-MailFrom: ravi.bangoria@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: Ravi Bangoria To: linux-kernel@vger.kernel.org Cc: acme@kernel.org, peterz@infradead.org, mingo@redhat.com, alexander.shishkin@linux.intel.com, mhiramat@kernel.org, wangnan0@huawei.com, namhyung@kernel.org, srikar@linux.vnet.ibm.com, naveen.n.rao@linux.vnet.ibm.com, Ravi Bangoria Subject: [RFC v2 2/2] perf probe: Fix module probe issue if no dwarf support Date: Tue, 26 Apr 2016 14:08:25 +0530 Message-Id: <1461659905-11147-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1461659905-11147-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com> References: <1461659905-11147-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16042608-0021-0000-0000-0000039F06F7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3283 Lines: 100 Perf is not able to register probe in kernel module when dwarf supprt is not there(and so it goes for symtab). Perf passes full path of module where only module name is required which is causing the problem. This patch fixes this issue. Before applying patch: $ dpkg -s libdw-dev dpkg-query: package 'libdw-dev' is not installed ... $ ./perf probe -m /linux/samples/kobject/kobject-example.ko foo_show Added new event: probe:foo_show (on foo_show in /linux/samples/kobject/kobject-example.ko) You can now use it in all perf tools, such as: perf record -e probe:foo_show -aR sleep 1 $ cat /sys/kernel/debug/tracing/kprobe_events p:probe/foo_show /linux/samples/kobject/kobject-example.ko:foo_show After applying patch: $ ./perf probe -m /linux/samples/kobject/kobject-example.ko foo_show Added new event: probe:foo_show (on foo_show in kobject_example) You can now use it in all perf tools, such as: perf record -e probe:foo_show -aR sleep 1 $ cat /sys/kernel/debug/tracing/kprobe_events p:probe/foo_show kobject_example:foo_show Signed-off-by: Ravi Bangoria --- Changes in v2: - made find_module_name static tools/perf/util/probe-event.c | 19 +++++++++++++++---- tools/perf/util/probe-event.h | 2 -- 2 files changed, 15 insertions(+), 6 deletions(-) diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index 5f1a9bf..c570a6c 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -285,7 +285,7 @@ static bool kprobe_warn_out_range(const char *symbol, unsigned long address) * inspect elf and find out what is actual module name. * Caller has to free mod_name after using it. */ -char *find_module_name(const char *module) +static char *find_module_name(const char *module) { int fd; Elf *elf; @@ -2566,6 +2566,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev, struct probe_trace_point *tp; int num_matched_functions; int ret, i, j, skipped = 0; + char *mod_name; map = get_target_map(pev->target, pev->uprobes); if (!map) { @@ -2650,9 +2651,19 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev, tp->realname = strdup_or_goto(sym->name, nomem_out); tp->retprobe = pp->retprobe; - if (pev->target) - tev->point.module = strdup_or_goto(pev->target, - nomem_out); + if (pev->target) { + if (pev->uprobes) { + tev->point.module = strdup_or_goto(pev->target, + nomem_out); + } else { + mod_name = find_module_name(pev->target); + tev->point.module = + strdup(mod_name ? mod_name : pev->target); + free(mod_name); + if (!tev->point.module) + goto nomem_out; + } + } tev->uprobes = pev->uprobes; tev->nargs = pev->nargs; if (tev->nargs) { diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h index 0468fa3..e54e7b0 100644 --- a/tools/perf/util/probe-event.h +++ b/tools/perf/util/probe-event.h @@ -166,6 +166,4 @@ int e_snprintf(char *str, size_t size, const char *format, ...) int copy_to_probe_trace_arg(struct probe_trace_arg *tvar, struct perf_probe_arg *pvar); -char *find_module_name(const char *module); - #endif /*_PROBE_EVENT_H */ -- 2.1.4