Messages in this thread Patch in this message | | | Subject | [PATCH -tip ] [BUGFIX/URGENT] perf-probe: Do not add offset to uprobe address | From | Masami Hiramatsu <> | Date | Wed, 05 Feb 2014 05:18:58 +0000 |
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Fix perf-probe not to add offset value to uprobe probe address when post processing. tevs[i].point.address 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 <masami.hiramatsu.pt@hitachi.com> --- 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 a8a9b6c..d8b048c 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);
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