From 981a23792cd02631f8cd5dd65753208a44de5ae1 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 5 Feb 2014 05:18:58 +0000 Subject: [PATCH] perf probe: Do not add offset twice to uprobe address 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 Cc: "David A. Long" Cc: David Ahern Cc: Ingo Molnar Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Srikar Dronamraju Cc: Steven Rostedt 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 --- 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); -- GitLab