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perf probe: Do not add offset twice to uprobe address

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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 fb7345bbf7

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: "David A. Long" <dave.long@linaro.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20140205051858.6519.27314.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu 2014-02-05 05:18:58 +00:00 committed by Arnaldo Carvalho de Melo
parent 0e9f2204cf
commit 981a23792c
1 changed files with 1 additions and 1 deletions
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2
tools/perf/util/probe-event.c
View file

@ -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);