Files
linux/tools/perf/util
Lexi Shao 1a86f4ba5c perf symbols: Ignore $a/$d symbols for ARM modules
On anARM machine, kernel symbols from modules can be resolved to $a
instead of printing the actual symbol name. Ignore symbols starting with
"$" when building kallsyms rbtree.

A sample stacktrace is shown as follows:

  c0f2e39c schedule_hrtimeout+0x14 ([kernel.kallsyms])
  bf4a66d8 $a+0x78 ([test_module])
  c0a4f5f4 kthread+0x15c ([kernel.kallsyms])
  c0a001f8 ret_from_fork+0x14 ([kernel.kallsyms])

On an ARM machine, $a/$d symbols are used by the compiler to mark the
beginning of code/data part in code section. These symbols are filtered
out when linking vmlinux(see scripts/kallsyms.c ignored_prefixes), but
are left on modules. So there are $a symbols in /proc/kallsyms which
share the same addresses with the actual module symbols and confuses
perf when resolving symbols.

After this patch, the module symbol name is printed:

  c0f2e39c schedule_hrtimeout+0x14 ([kernel.kallsyms])
  bf4a66d8 test_func+0x78 ([test_module])
  c0a4f5f4 kthread+0x15c ([kernel.kallsyms])
  c0a001f8 ret_from_fork+0x14 ([kernel.kallsyms])

Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Lexi Shao <shaolexi@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: QiuXi <qiuxi1@huawei.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Wangbing <wangbing6@huawei.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
Link: https://lore.kernel.org/r/20211029065038.39449-2-shaolexi@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-11-07 12:27:38 -03:00
..
2019-02-19 16:11:56 -03:00
2019-02-19 16:11:56 -03:00
2020-10-14 13:34:26 -03:00
2021-09-03 08:15:10 -03:00
2021-04-29 10:30:58 -03:00
2021-08-11 09:35:44 -03:00
2021-08-11 09:35:44 -03:00
2021-10-20 10:59:17 -03:00
2021-10-20 10:59:17 -03:00
2021-02-03 13:10:44 -03:00
2021-07-15 17:30:22 -03:00
2021-09-17 08:55:00 -03:00
2019-01-25 15:12:09 +01:00
2020-10-14 13:34:26 -03:00
2021-02-17 15:15:06 -03:00
2021-02-17 15:15:06 -03:00
2020-04-18 09:05:01 -03:00
2020-04-18 09:05:01 -03:00