linux-kernel - [PATCH] perf probe: Fix failure to add multiple probes without debuginfo

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1426759324-32538-1-git-send-email-hekuang@huawei.com>
Date:	Thu, 19 Mar 2015 18:02:04 +0800
From:	He Kuang <hekuang@...wei.com>
To:	<acme@...nel.org>, <masami.hiramatsu.pt@...achi.com>,
	<a.p.zijlstra@...llo.nl>, <mingo@...hat.com>, <namhyung@...nel.org>
CC:	<wangnan0@...wei.com>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] perf probe: Fix failure to add multiple probes without debuginfo

Perf tries to find probe function addresses from map when debuginfo
could not be found.

To the first added function, the value of ref_reloc_sym was set in
maps__set_kallsyms_ref_reloc_sym() and can be obtained from
host_machine->kmaps->maps. After that, new maps are added to
host_machine->kmaps->maps in dso__load_kcore(), all these new added maps
do not have a valid ref_reloc_sym.

When adding a second function, get_target_map() may get a map without
valid ref_reloc_sym, and raise the error "Relocated base symbol is not
found".

Fix this by getting ref_reloc_sym from machine->vmlinux_maps.

This problem can be reproduced as following:

  $ perf probe --add='sys_write' --add='sys_open'
  Relocated base symbol is not found!
    Error: Failed to add events.

After this patch:

  $ perf probe --add='sys_write' --add='sys_open'
  Added new event:
    probe:sys_write      (on sys_write)

  You can now use it in all perf tools, such as:

      perf record -e probe:sys_write -aR sleep 1

  Added new event:
    probe:sys_open       (on sys_open)

  You can now use it in all perf tools, such as:

      perf record -e probe:sys_open -aR sleep 1

Signed-off-by: He Kuang <hekuang@...wei.com>
---
 tools/perf/util/probe-event.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index c5e1338..75d41ee 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2540,7 +2540,19 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 	}
 
 	if (!pev->uprobes && !pp->retprobe) {
-		kmap = map__kmap(map);
+		struct machine *machine;
+		struct map *vmlinux_map = NULL;
+
+		if (map->groups && map->groups->machine) {
+			machine = map->groups->machine;
+			vmlinux_map = machine->vmlinux_maps[MAP__FUNCTION];
+		}
+
+		if (vmlinux_map)
+			kmap = map__kmap(vmlinux_map);
+		else
+			kmap = map__kmap(map);
+
 		reloc_sym = kmap->ref_reloc_sym;
 		if (!reloc_sym) {
 			pr_warning("Relocated base symbol is not found!\n");
-- 
2.3.3.220.g9ab698f

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/