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 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:
parent
0e9f2204cf
commit
981a23792c
@ -336,8 +336,8 @@ static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
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return ret;
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return ret;
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for (i = 0; i < ntevs && ret >= 0; i++) {
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for (i = 0; i < ntevs && ret >= 0; i++) {
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/* point.address is the addres of point.symbol + point.offset */
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offset = tevs[i].point.address - stext;
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offset = tevs[i].point.address - stext;
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offset += tevs[i].point.offset;
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tevs[i].point.offset = 0;
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tevs[i].point.offset = 0;
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zfree(&tevs[i].point.symbol);
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zfree(&tevs[i].point.symbol);
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ret = e_snprintf(buf, 32, "0x%lx", offset);
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ret = e_snprintf(buf, 32, "0x%lx", offset);
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