Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751100AbdCOSnl (ORCPT ); Wed, 15 Mar 2017 14:43:41 -0400 Received: from terminus.zytor.com ([65.50.211.136]:39612 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751416AbdCOSnW (ORCPT ); Wed, 15 Mar 2017 14:43:22 -0400 Date: Wed, 15 Mar 2017 11:43:03 -0700 From: "tip-bot for Naveen N. Rao" Message-ID: Cc: acme@redhat.com, mpe@ellerman.id.au, linux-kernel@vger.kernel.org, naveen.n.rao@linux.vnet.ibm.com, tglx@linutronix.de, mingo@kernel.org, rostedt@goodmis.org, hpa@zytor.com, ananth@linux.vnet.ibm.com, mhiramat@kernel.org Reply-To: ananth@linux.vnet.ibm.com, hpa@zytor.com, mhiramat@kernel.org, acme@redhat.com, mpe@ellerman.id.au, linux-kernel@vger.kernel.org, tglx@linutronix.de, naveen.n.rao@linux.vnet.ibm.com, rostedt@goodmis.org, mingo@kernel.org In-Reply-To: <496ef9f33c1ab16286ece9dd62aa672807aef91c.1488961018.git.naveen.n.rao@linux.vnet.ibm.com> References: <496ef9f33c1ab16286ece9dd62aa672807aef91c.1488961018.git.naveen.n.rao@linux.vnet.ibm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf kretprobes: Offset from reloc_sym if kernel supports it Git-Commit-ID: 7ab31d94bff96f4f80b38dc5147622b9f3889ac6 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7082 Lines: 177 Commit-ID: 7ab31d94bff96f4f80b38dc5147622b9f3889ac6 Gitweb: http://git.kernel.org/tip/7ab31d94bff96f4f80b38dc5147622b9f3889ac6 Author: Naveen N. Rao AuthorDate: Wed, 8 Mar 2017 13:56:09 +0530 Committer: Arnaldo Carvalho de Melo CommitDate: Tue, 14 Mar 2017 15:17:39 -0300 perf kretprobes: Offset from reloc_sym if kernel supports it We indicate support for accepting sym+offset with kretprobes through a line in ftrace README. Parse the same to identify support and choose the appropriate format for kprobe_events. As an example, without this perf patch, but with the ftrace changes: naveen@ubuntu:~/linux/tools/perf$ sudo cat /sys/kernel/debug/tracing/README | grep kretprobe place (kretprobe): [:][+]| naveen@ubuntu:~/linux/tools/perf$ naveen@ubuntu:~/linux/tools/perf$ sudo ./perf probe -v do_open%return probe-definition(0): do_open%return symbol:do_open file:(null) line:0 offset:0 return:1 lazy:(null) 0 arguments Looking at the vmlinux_path (8 entries long) Using /boot/vmlinux for symbols Open Debuginfo file: /boot/vmlinux Try to find probe point from debuginfo. Matched function: do_open [2d0c7d8] Probe point found: do_open+0 Matched function: do_open [35d76b5] found inline addr: 0xc0000000004ba984 Failed to find "do_open%return", because do_open is an inlined function and has no return point. An error occurred in debuginfo analysis (-22). Trying to use symbols. Opening /sys/kernel/debug/tracing//kprobe_events write=1 Writing event: r:probe/do_open do_open+0 Writing event: r:probe/do_open_1 do_open+0 Added new events: probe:do_open (on do_open%return) probe:do_open_1 (on do_open%return) You can now use it in all perf tools, such as: perf record -e probe:do_open_1 -aR sleep 1 naveen@ubuntu:~/linux/tools/perf$ sudo cat /sys/kernel/debug/kprobes/list c000000000041370 k kretprobe_trampoline+0x0 [OPTIMIZED] c0000000004433d0 r do_open+0x0 [DISABLED] c0000000004433d0 r do_open+0x0 [DISABLED] And after this patch (and the subsequent powerpc patch): naveen@ubuntu:~/linux/tools/perf$ sudo ./perf probe -v do_open%return probe-definition(0): do_open%return symbol:do_open file:(null) line:0 offset:0 return:1 lazy:(null) 0 arguments Looking at the vmlinux_path (8 entries long) Using /boot/vmlinux for symbols Open Debuginfo file: /boot/vmlinux Try to find probe point from debuginfo. Matched function: do_open [2d0c7d8] Probe point found: do_open+0 Matched function: do_open [35d76b5] found inline addr: 0xc0000000004ba984 Failed to find "do_open%return", because do_open is an inlined function and has no return point. An error occurred in debuginfo analysis (-22). Trying to use symbols. Opening /sys/kernel/debug/tracing//README write=0 Opening /sys/kernel/debug/tracing//kprobe_events write=1 Writing event: r:probe/do_open _text+4469712 Writing event: r:probe/do_open_1 _text+4956248 Added new events: probe:do_open (on do_open%return) probe:do_open_1 (on do_open%return) You can now use it in all perf tools, such as: perf record -e probe:do_open_1 -aR sleep 1 naveen@ubuntu:~/linux/tools/perf$ sudo cat /sys/kernel/debug/kprobes/list c000000000041370 k kretprobe_trampoline+0x0 [OPTIMIZED] c0000000004433d0 r do_open+0x0 [DISABLED] c0000000004ba058 r do_open+0x8 [DISABLED] Signed-off-by: Naveen N. Rao Acked-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Michael Ellerman Cc: Steven Rostedt Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/496ef9f33c1ab16286ece9dd62aa672807aef91c.1488961018.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/probe-event.c | 12 +++++------- tools/perf/util/probe-file.c | 7 +++++++ tools/perf/util/probe-file.h | 1 + 3 files changed, 13 insertions(+), 7 deletions(-) diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index 28fb62c..c9bdc9d 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -757,7 +757,9 @@ post_process_kernel_probe_trace_events(struct probe_trace_event *tevs, } for (i = 0; i < ntevs; i++) { - if (!tevs[i].point.address || tevs[i].point.retprobe) + if (!tevs[i].point.address) + continue; + if (tevs[i].point.retprobe && !kretprobe_offset_is_supported()) continue; /* If we found a wrong one, mark it by NULL symbol */ if (kprobe_warn_out_range(tevs[i].point.symbol, @@ -1528,11 +1530,6 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev) return -EINVAL; } - if (pp->retprobe && !pp->function) { - semantic_error("Return probe requires an entry function.\n"); - return -EINVAL; - } - if ((pp->offset || pp->line || pp->lazy_line) && pp->retprobe) { semantic_error("Offset/Line/Lazy pattern can't be used with " "return probe.\n"); @@ -2841,7 +2838,8 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev, } /* Note that the symbols in the kmodule are not relocated */ - if (!pev->uprobes && !pp->retprobe && !pev->target) { + if (!pev->uprobes && !pev->target && + (!pp->retprobe || kretprobe_offset_is_supported())) { reloc_sym = kernel_get_ref_reloc_sym(); if (!reloc_sym) { pr_warning("Relocated base symbol is not found!\n"); diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c index 8a219cd..1542cd0 100644 --- a/tools/perf/util/probe-file.c +++ b/tools/perf/util/probe-file.c @@ -879,6 +879,7 @@ int probe_cache__show_all_caches(struct strfilter *filter) enum ftrace_readme { FTRACE_README_PROBE_TYPE_X = 0, + FTRACE_README_KRETPROBE_OFFSET, FTRACE_README_END, }; @@ -889,6 +890,7 @@ static struct { #define DEFINE_TYPE(idx, pat) \ [idx] = {.pattern = pat, .avail = false} DEFINE_TYPE(FTRACE_README_PROBE_TYPE_X, "*type: * x8/16/32/64,*"), + DEFINE_TYPE(FTRACE_README_KRETPROBE_OFFSET, "*place (kretprobe): *"), }; static bool scan_ftrace_readme(enum ftrace_readme type) @@ -939,3 +941,8 @@ bool probe_type_is_available(enum probe_type type) return true; } + +bool kretprobe_offset_is_supported(void) +{ + return scan_ftrace_readme(FTRACE_README_KRETPROBE_OFFSET); +} diff --git a/tools/perf/util/probe-file.h b/tools/perf/util/probe-file.h index a17a82e..dbf95a0 100644 --- a/tools/perf/util/probe-file.h +++ b/tools/perf/util/probe-file.h @@ -65,6 +65,7 @@ struct probe_cache_entry *probe_cache__find_by_name(struct probe_cache *pcache, const char *group, const char *event); int probe_cache__show_all_caches(struct strfilter *filter); bool probe_type_is_available(enum probe_type type); +bool kretprobe_offset_is_supported(void); #else /* ! HAVE_LIBELF_SUPPORT */ static inline struct probe_cache *probe_cache__new(const char *tgt __maybe_unused) {