Commit 4708bbda5c ("tools lib bpf: Fix maps resolution") attempted to
fix map resolution by identifying the number of symbols that point to
maps, and using this number to resolve each of the maps.
However, during relocation the original definition of the map size was
still in use. For up to two maps, the calculation was correct if there
was a small difference in size between the map definition in libbpf and
the one that the client library uses. However if the difference was
large, particularly if more than two maps were used in the BPF program,
the relocation would fail.
For example, when using a map definition with size 28, with three maps,
map relocation would count:
(sym_offset / sizeof(struct bpf_map_def) => map_idx)
(0 / 16 => 0), ie map_idx = 0
(28 / 16 => 1), ie map_idx = 1
(56 / 16 => 3), ie map_idx = 3
So, libbpf reports:
libbpf: bpf relocation: map_idx 3 large than 2
Fix map relocation by checking the exact offset of maps when doing
relocation.
Signed-off-by: Joe Stringer <joe@ovn.org>
[Allow different map size in an object]
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: netdev@vger.kernel.org
Fixes: 4708bbda5c ("tools lib bpf: Fix maps resolution")
Link: http://lkml.kernel.org/r/20170123011128.26534-2-joe@ovn.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Using perf with call graph method dwarf fails to provide backtrace
support for stripped binary even though .gnu_debuglink points to *.dbg
flavor with properly populated debug symbols.
Problem is reproduced on ARM (v7, v8), kernels 3.14.y, 4.4.y and
4.10.rc3. Perf is configured with libunwind, and unwind dwarf support
[1]. Test code (stress_bt.c) can be found on [2].
Running (explicitly disable other unwinding methods):
$ gcc -g -o stress_bt -fomit-frame-pointer -fno-unwind-tables \
-fno-asynchronous-unwind-tables stress_bt.c
$ perf record -N --call-graph dwarf ./stress_bt
$ perf report
results in properly generated call graph. Stripping the binary and running
it results with missing call graph. Expected result is to have call graph:
$ gcc -g -o stress_bt -fomit-frame-pointer -fno-unwind-tables \
-fno-asynchronous-unwind-tables stress_bt.c
$ objcopy --only-keep-debug stress_bt stress_bt.dbg
$ objcopy --strip-debug stress_bt
$ objcopy --add-gnu-debuglink=stress_bt.dbg stress_bt
$ perf record -N --call-graph dwarf ./stress_bt
$ perf report
Problem is that perf doesn't try to read symbols pointed by gnu
debuglink. Patch adds checking, and reading of the symbols from
debuglink and symsrc. Order of the check is to first check within dso,
then check whether symsrc is defined and try to read from it. Finally,
debuglink is checked. Default locations of debug files are discussed in
[3] and [4]. Comments on RFC are on [5].
[1] https://wiki.linaro.org/LEG/Engineering/TOOLS/perf-callstack-unwinding
[2] [1]#Backtrace_stress_application
[3] https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html
[4] https://sourceware.org/binutils/docs/binutils/objcopy.html
[5] https://lkml.org/lkml/2016/8/22/473
Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/d309d40a-463f-482b-68e1-1465326efdc1@nokia.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:
New features:
- Account thread wait time (off CPU time) separately: sleep, iowait and
preempt, based on the prev_state of the last event, show the breakdown
when using "perf sched timehist --state" (Namhyumg Kim)
Infrastructure changes:
- Factor out PMU scale conversion code (Andi Kleen)
- Remove unnecessary feature-dwarf warning (David Carrillo-Cisneros)
- Add missing member name in OPT_() macros (Soramichi AKIYAMA)
- Move variables referenced in libperf.a object files from perf's main()
file, so that other tools can use libperf.a with a different main()
(Soramichi AKIYAMA)
Documentation changes:
- Fix 'perf script' man page about --dump-raw-trace option (Michael Petlan)
- Also allow forcing reading of non-root owned files by root in 'perf
script' (Yannick Brosseau)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The use_browser and perf_version_string variables are both declared in
perf.c but they are also referenced by other functions of libperf.a.
Therefore a user linking an own main() with libperf.a must declare those
two variables in their files even if the files never use the browser or
the version information.
This patch fixes this issue by moving use_browser and
perf_version_string out of perf.c to some other files.
Signed-off-by: Soramichi Akiyama <akiyama@m.soramichi.jp>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170117002237.c1aec0ce3b4d675dca018deb@m.soramichi.jp
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The --state option is to show task state when switched out. The state
is printed as a single character like in the /proc but I added 'I' for
idle state rather than 'R'.
$ perf sched timehist --state | head
Samples do not have callchains.
time cpu task name wait time sch delay run time state
[tid/pid] (msec) (msec) (msec)
-------- --- ----------------------- -------- ------------------ -----
1.753791 [3] <idle> 0.000 0.000 0.000 I
1.753834 [1] perf[27469] 0.000 0.000 0.000 S
1.753904 [3] perf[27470] 0.000 0.006 0.112 S
1.753914 [1] <idle> 0.000 0.000 0.079 I
1.753915 [3] migration/3[23] 0.000 0.002 0.011 S
1.754287 [2] <idle> 0.000 0.000 0.000 I
1.754335 [2] transmission[1773/1739] 0.000 0.004 0.047 S
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170113104523.31212-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Namhyung Kim
Arnaldo Carvalho de Melo
Joe Stringer
Markus Elfring
He Kuang
Jiri Olsa
Matija Glavinic Pecotic
Ingo Molnar
Soramichi AKIYAMA
Namhyung Kim
Yannick Brosseau
Michael Petlan