[RFC PATCH 2/8] perf probe powerpc: Fix symbol fixup issues due to ELF type

Naveen N. Rao naveen.n.rao at linux.vnet.ibm.com
Wed Dec 10 04:34:00 AEDT 2014


If using the symbol table, symbol addresses are not being fixed up
properly, resulting in probes being placed at wrong addresses:

  # perf probe do_fork
  Added new event:
    probe:do_fork        (on do_fork)

  You can now use it in all perf tools, such as:

	  perf record -e probe:do_fork -aR sleep 1

  # cat /sys/kernel/debug/tracing/kprobe_events
  p:probe/do_fork _text+635952
  # printf "%x" 635952
  9b430
  # grep do_fork /boot/System.map
  c0000000000ab430 T .do_fork

Fix by checking for ELF type ET_DYN used by ppc64 kernels.

Signed-off-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>
---
 tools/perf/util/symbol-elf.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 1e23a5b..67e4392 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -629,7 +629,8 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 						     NULL) != NULL);
 	} else {
 		ss->adjust_symbols = ehdr.e_type == ET_EXEC ||
-				     ehdr.e_type == ET_REL;
+				     ehdr.e_type == ET_REL ||
+				     ehdr.e_type == ET_DYN;
 	}
 
 	ss->name   = strdup(name);
-- 
2.1.3



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