From: Namhyung Kim <namhy...@kernel.org>
The decompress_kmodule() decompresses kernel modules in order to load
symbols from it. In the DSO_BINARY_TYPE__BUILD_ID_CACHE case, it needs
the full file path to extract the file extension to determine the
decompression method. But overwriting 'name' will fail the
decompression since it might point to a non-existing old file.
Instead, use dso->long_name for having the correct extension and use the
real filename to decompress.
In the DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP case, both names should
be the same. This allows resolving symbols in the old modules.
Before:
$ perf report -i perf.data.old | grep scsi_mod
0.00% cc1 [scsi_mod] [k] 0x0000000000004aa6
0.00% as [scsi_mod] [k] 0x00000000000099e1
0.00% cc1 [scsi_mod] [k] 0x0000000000009830
0.00% cc1 [scsi_mod] [k] 0x0000000000001b8f
After:
0.00% cc1 [scsi_mod] [k] scsi_handle_queue_ramp_up
0.00% as [scsi_mod] [k] scsi_sg_alloc
0.00% cc1 [scsi_mod] [k] scsi_setup_cmnd
0.00% cc1 [scsi_mod] [k] scsi_get_command
Signed-off-by: Namhyung Kim <namhy...@kernel.org>
Acked-by: Jiri Olsa <jo...@kernel.org>
Cc: Andi Kleen <a...@firstfloor.org>
Cc: David Ahern <dsah...@gmail.com>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: kernel-t...@lge.com
Link: http://lkml.kernel.org/r/20170531120105.21731-3-namhy...@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
---
tools/perf/util/symbol-elf.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index e7ee47f7377a..1fb2efae4f02 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -649,10 +649,7 @@ static int decompress_kmodule(struct dso *dso, const char
*name,
type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
return -1;
- if (type == DSO_BINARY_TYPE__BUILD_ID_CACHE)
- name = dso->long_name;
-
- if (kmod_path__parse_ext(&m, name) || !m.comp)
+ if (kmod_path__parse_ext(&m, dso->long_name) || !m.comp)
return -1;
fd = mkstemp(tmpbuf);
--
2.9.4
