From: Masami Hiramatsu <[email protected]>
Fix perf-probe not to add offset value twice to uprobe probe address
when post processing.
The tevs[i].point.address struct member is the address of symbol+offset,
but current perf-probe adjusts the point.address by adding the offset.
As a result, the probe address becomes symbol+offset+offset. This may
cause unexpected code corruption. Urgent fix is needed.
Without this fix:
---
# ./perf probe -x ./perf dso__load_vmlinux+4
# ./perf probe -l
probe_perf:dso__load_vmlinux (on 0x000000000006d2b8)
# nm ./perf.orig | grep dso__load_vmlinux\$
000000000046d0a0 T dso__load_vmlinux
---
You can see the given offset is 3 but the actual probed address is
dso__load_vmlinux+8.
With this fix:
---
# ./perf probe -x ./perf dso__load_vmlinux+4
# ./perf probe -l
probe_perf:dso__load_vmlinux (on 0x000000000006d2b4)
---
Now the problem is fixed.
Note: This bug is introduced by
commit fb7345bbf7fad9bf72ef63a19c707970b9685812
Signed-off-by: Masami Hiramatsu <[email protected]>
Cc: "David A. Long" <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Srikar Dronamraju <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: [email protected]
Link:
http://lkml.kernel.org/r/20140205051858.6519.27314.st...@kbuild-fedora.yrl.intra.hitachi.co.jp
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/util/probe-event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index a8a9b6cd93a8..d8b048c20cde 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -336,8 +336,8 @@ static int add_exec_to_probe_trace_events(struct
probe_trace_event *tevs,
return ret;
for (i = 0; i < ntevs && ret >= 0; i++) {
+ /* point.address is the addres of point.symbol + point.offset */
offset = tevs[i].point.address - stext;
- offset += tevs[i].point.offset;
tevs[i].point.offset = 0;
zfree(&tevs[i].point.symbol);
ret = e_snprintf(buf, 32, "0x%lx", offset);
--
1.8.1.4
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