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Namhyung Kim 25dd9171f5 perf probe: Fix probing kretprobes 
The commit dfef99cd0b ("perf probe: Use ref_reloc_sym based address
instead of the symbol name") converts kprobes to use ref_reloc_sym (i.e.
_stext) and offset instead of using symbol's name directly.  So on my
system, adding do_fork ends up with like below:

  $ sudo perf probe -v --add do_fork%return
  probe-definition(0): do_fork%return
  symbol:do_fork file:(null) line:0 offset:0 return:1 lazy:(null)
  0 arguments
  Looking at the vmlinux_path (7 entries long)
  Using /lib/modules/3.17.6-1-ARCH/build/vmlinux for symbols
  Could not open debuginfo. Try to use symbols.
  Opening /sys/kernel/debug/tracing/kprobe_events write=1
  Added new event:
  Writing event: r:probe/do_fork _stext+456136
  Failed to write event: Invalid argument
  Error: Failed to add events. Reason: Operation not permitted (Code: -1)

As you can see, the do_fork was translated to _stext+456136.  This was
because to support (local) symbols that have same name.  But the problem
is that kretprobe requires to be inserted at function start point so it
simply checks whether it's called with offset 0.  And if not, it'll
return with -EINVAL.  You can see it with dmesg.

  $ dmesg | tail -1
    [125621.764103] Return probe must be used without offset.

So we need to use the symbol name instead of ref_reloc_sym in case of
return probes.

Reported-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/1421234288-22758-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-01-21 10:06:24 -03:00
..
cgroup
firewire
hv tools: hv: ignore ENOBUFS and ENOMEM in the KVP daemon 2014-11-26 19:01:12 -08:00
include tools: Remove bitops/hweight usage of bits in tools/perf 2015-01-16 17:49:29 -03:00
lguest tools/lguest: offer VIRTIO_F_ANY_LAYOUT for net device. 2013-07-15 11:18:32 +09:30
lib perf tools: Fix statfs.f_type data type mismatch build error with uclibc 2015-01-16 17:49:29 -03:00
net tools: bpf_jit_disasm: increase image buffer size 2014-05-16 16:44:08 -04:00
nfsd
perf perf probe: Fix probing kretprobes 2015-01-21 10:06:24 -03:00
power tools / cpupower: Fix no idle state information return value 2014-12-19 23:01:12 +01:00
scripts tools lib traceevent: Add global QUIET_CC_FPIC build output 2013-12-19 16:18:10 -03:00
testing selftests/vm: fix link error for transhuge-stress test 2015-01-08 09:01:00 -07:00
thermal/tmon calloc/xcalloc: Fix argument order 2014-12-09 10:06:29 -03:00
time tools: add script to test udelay 2014-07-23 10:16:38 -07:00
usb USB patches for 3.19-rc1 2014-12-14 14:57:16 -08:00
virtio tools/virtio: add virtio 1.0 in vringh_test 2014-12-15 23:49:22 +02:00
vm mm/page_owner: keep track of page owners 2014-12-13 12:42:48 -08:00
Makefile tools/liblockdep: Build liblockdep from tools/Makefile 2014-05-08 13:34:45 -04:00