From e7ee404757609067c8f261d90251f1e96459c535 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Fri, 5 Feb 2016 14:01:27 +0000 Subject: perf symbols: Fix symbols searching for module in buildid-cache Before this patch, if a sample is triggered inside a module not in /lib/modules/`uname -r`/, even if the module is in buildid-cache, 'perf report' will still be unable to find the correct symbol. For example: # rm -rf ~/.debug/ # perf buildid-cache -a ./mymodule.ko # perf probe -m ./mymodule.ko -a get_mymodule_val Added new event: probe:get_mymodule_val (on get_mymodule_val in mymodule) You can now use it in all perf tools, such as: perf record -e probe:get_mymodule_val -aR sleep 1 # perf record -e probe:get_mymodule_val cat /proc/mymodule mymodule:3 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.011 MB perf.data (1 samples) ] # perf report --stdio [SNIP] # # Overhead Command Shared Object Symbol # ........ ....... ................ ...................... # 100.00% cat [mymodule] [k] 0x0000000000000001 # perf report -vvvv --stdio dso__load_sym: adjusting symbol: st_value: 0 sh_addr: 0 sh_offset: 0x70 symbol__new: get_mymodule_val 0x70-0x8a [SNIP] This is caused by dso__load() -> dso__load_sym(). In dso__load(), kmod is true only when its file is found in some well know directories. All files loaded from buildid-cache are treated as user programs. Following dso__load_sym() set map->pgoff incorrectly. This patch gives kernel modules in buildid-cache a chance to adjust value of kmod. After dso__load() get the type of symbols, if it is buildid, check the last 3 chars of original filename against '.ko', and adjust the value of kmod if the file is a kernel module. Signed-off-by: Wang Nan Cc: Adrian Hunter Cc: Alexei Starovoitov Cc: Brendan Gregg Cc: Cody P Schafer Cc: He Kuang Cc: Jeremie Galarneau Cc: Jiri Olsa Cc: Kirill Smelkov Cc: Li Zefan Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1454680939-24963-3-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/build-id.h | 1 + 1 file changed, 1 insertion(+) (limited to 'tools/perf/util/build-id.h') diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h index 27a14a8..64af3e2 100644 --- a/tools/perf/util/build-id.h +++ b/tools/perf/util/build-id.h @@ -16,6 +16,7 @@ int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id); int filename__sprintf_build_id(const char *pathname, char *sbuild_id); char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size); +bool dso__build_id_is_kmod(const struct dso *dso, char *bf, size_t size); int build_id__mark_dso_hit(struct perf_tool *tool, union perf_event *event, struct perf_sample *sample, struct perf_evsel *evsel, -- cgit v1.1