linux/tools/perf
Wang Nan 1c0bd0e891 perf probe: Try to use symbol table if searching debug info failed
A problem can occur in a statically linked perf when vmlinux can be found:

 # perf probe --add sys_epoll_pwait
 probe-definition(0): sys_epoll_pwait
 symbol:sys_epoll_pwait file:(null) line:0 offset:0 return:0 lazy:(null)
 0 arguments
 Looking at the vmlinux_path (7 entries long)
 Using /lib/modules/4.2.0-rc1+/build/vmlinux for symbols
 Open Debuginfo file: /lib/modules/4.2.0-rc1+/build/vmlinux
 Try to find probe point from debuginfo.
 Symbol sys_epoll_pwait address found : ffffffff8122bd40
 Matched function: SyS_epoll_pwait
 Failed to get call frame on 0xffffffff8122bd40
 An error occurred in debuginfo analysis (-2).
   Error: Failed to add events. Reason: No such file or directory (Code: -2)

The reason is caused by libdw that, if libdw is statically linked, it
can't load libebl_{arch}.so reliable.

In this case it is still possible to get the address from
/proc/kalksyms.  However, perf tries that only when libdw returns
-EBADF.

This patch gives it another chance to utilize symbol table, even if
libdw returns an error code other than -EBADF.

After applying this patch:

 # perf probe -nv --add sys_epoll_pwait
 probe-definition(0): sys_epoll_pwait
 symbol:sys_epoll_pwait file:(null) line:0 offset:0 return:0 lazy:(null)
 0 arguments
 Looking at the vmlinux_path (7 entries long)
 Using /lib/modules/4.2.0-rc1+/build/vmlinux for symbols
 Open Debuginfo file: /lib/modules/4.2.0-rc1+/build/vmlinux
 Try to find probe point from debuginfo.
 Symbol sys_epoll_pwait address found : ffffffff8122bd40
 Matched function: SyS_epoll_pwait
 Failed to get call frame on 0xffffffff8122bd40
 An error occurred in debuginfo analysis (-2).
 Trying to use symbols.
 Opening /sys/kernel/debug/tracing/kprobe_events write=1
 Added new event:
 Writing event: p:probe/sys_epoll_pwait _text+2276672
   probe:sys_epoll_pwait (on sys_epoll_pwait)

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

 	perf record -e probe:sys_epoll_pwait -aR sleep 1

Although libdw returns an error (Failed to get call frame), perf tries
symbol table and finally gets correct address.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1440151770-129878-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-08-21 12:57:20 -03:00
..
Documentation perf tools: Put itrace options into an asciidoc include 2015-08-21 11:40:44 -03:00
arch perf tools: Add Intel BTS support 2015-08-21 11:34:10 -03:00
bench perf bench futex: Add lock_pi stresser 2015-07-20 17:49:51 -03:00
config perf tools: Support static linking with libdw 2015-08-13 14:49:11 -03:00
python perf python: Make twatch.py use soft dummy event, freq=0 2015-07-29 10:51:45 -03:00
scripts perf tools: Add example call-graph script 2015-08-21 12:32:40 -03:00
tests perf tests: Add tests to callgraph and time parse 2015-08-12 13:20:29 -03:00
trace/strace/groups perf trace: Support 'strace' syscall event groups 2015-07-20 15:16:32 -03:00
ui perf report: Show call graph from reference events 2015-08-12 13:20:28 -03:00
util perf probe: Try to use symbol table if searching debug info failed 2015-08-21 12:57:20 -03:00
.gitignore perf tools: Add Intel PT instruction decoder 2015-08-17 11:11:36 -03:00
Build perf trace: Support 'strace' syscall event groups 2015-07-20 15:16:32 -03:00
CREDITS
MANIFEST perf tests: Add LLVM test for eBPF on-the-fly compiling 2015-08-07 10:57:24 -03:00
Makefile perf build: Fix single target build dependency check 2015-06-22 11:27:09 -03:00
Makefile.perf perf tools: Add Intel PT instruction decoder 2015-08-17 11:11:36 -03:00
builtin-annotate.c perf callchain: Allow disabling call graphs per event 2015-08-12 13:20:28 -03:00
builtin-bench.c perf bench futex: Add lock_pi stresser 2015-07-20 17:49:51 -03:00
builtin-buildid-cache.c perf buildid: Use SBUILD_ID_SIZE macro 2015-07-20 17:49:50 -03:00
builtin-buildid-list.c perf buildid: Use SBUILD_ID_SIZE macro 2015-07-20 17:49:50 -03:00
builtin-data.c perf data: Support using -f to override perf.data file ownership for 'convert' 2015-04-02 13:18:52 -03:00
builtin-diff.c perf callchain: Allow disabling call graphs per event 2015-08-12 13:20:28 -03:00
builtin-evlist.c perf evlist: Support using -f to override perf.data file ownership 2015-04-02 13:18:45 -03:00
builtin-help.c perf tools: Add the bash completion for listing subsubcommands of perf help 2015-03-19 13:49:39 -03:00
builtin-inject.c perf tools: Add new PERF_RECORD_SWITCH event 2015-07-23 22:51:13 -03:00
builtin-kmem.c perf kmem: Fill in the missing session freeing after an error occurs 2015-07-01 17:53:49 -03:00
builtin-kvm.c perf kvm: Fill in the missing session freeing after an error occurs 2015-07-01 17:53:49 -03:00
builtin-list.c perf list: Extend raw-dump to certain kind of events 2015-02-27 15:52:24 -03:00
builtin-lock.c perf machine: Protect the machine->threads with a rwlock 2015-05-08 16:19:27 -03:00
builtin-mem.c perf mem: Fill in the missing session freeing after an error occurs 2015-07-01 17:53:49 -03:00
builtin-probe.c perf probe: Delete an unnecessary check before the function call "strfilter__delete" 2015-07-06 08:58:36 -03:00
builtin-record.c Merge branch 'perf/urgent' into perf/core, to pick up fixes before adding more changes 2015-08-20 11:48:56 +02:00
builtin-report.c perf report: Show call graph from reference events 2015-08-12 13:20:28 -03:00
builtin-sched.c perf sched: Add option to merge like comms to lat output 2015-05-27 12:21:45 -03:00
builtin-script.c perf script: Initialize callchain_param.record_mode 2015-08-17 10:48:39 -03:00
builtin-stat.c perf stat: Move perf_counts struct and functions into separate object 2015-08-08 14:16:49 -03:00
builtin-timechart.c perf tools: Elliminate alignment holes 2015-05-18 10:17:33 -03:00
builtin-top.c Merge branch 'perf/urgent' into perf/core, to pick up fixes before adding more changes 2015-08-20 11:48:56 +02:00
builtin-trace.c perf trace: Move vfs_getname storage to per thread area 2015-08-14 13:16:27 -03:00
builtin.h perf tools: Add new 'perf data' command 2015-02-25 12:42:25 -03:00
command-list.txt perf tools: Add new 'perf data' command 2015-02-25 12:42:25 -03:00
design.txt perf tools: Update some code references in design.txt 2014-03-18 18:17:06 -03:00
perf-archive.sh
perf-completion.sh perf tools: Avoid confusion with preloaded bash function for perf bash completion 2015-03-19 13:53:27 -03:00
perf-read-vdso.c perf tools: Build programs to copy 32-bit compatibility 2014-10-29 10:32:48 -02:00
perf-sys.h perf tools: Move generic barriers out of perf-sys.h 2015-05-08 16:05:08 -03:00
perf-with-kcore.sh perf tools: Fix perf-with-kcore handling of arguments containing spaces 2015-08-06 16:48:27 -03:00
perf.c perf tools: Fix the bash completion problem of 'perf --*' 2015-02-27 15:52:28 -03:00
perf.h perf tools: Introduce callgraph_set for callgraph option 2015-07-29 16:18:45 -03:00