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| author | Lexi Shao <shaolexi@huawei.com> | 2021-10-29 14:50:37 +0800 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2021-11-07 12:27:38 -0300 |
| commit | 1a86f4ba5cf1c19b55a12be8e5e9235a23921f8d (patch) | |
| tree | 4e8370bf59e5a84755f1830059bdab4435323928 /tools/perf/util | |
| parent | eb39bf325631f9ae185abd16281079b7b9858737 (diff) | |
| download | linux-1a86f4ba5cf1c19b55a12be8e5e9235a23921f8d.tar.bz2 | |
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 $a symbols in /proc/kallsyms which
share the same addresses with the actual module symbols and confuses
perf when resolving symbols.
After this patch, the module symbol name is printed:
c0f2e39c schedule_hrtimeout+0x14 ([kernel.kallsyms])
bf4a66d8 test_func+0x78 ([test_module])
c0a4f5f4 kthread+0x15c ([kernel.kallsyms])
c0a001f8 ret_from_fork+0x14 ([kernel.kallsyms])
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Lexi Shao <shaolexi@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: QiuXi <qiuxi1@huawei.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Wangbing <wangbing6@huawei.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
Link: https://lore.kernel.org/r/20211029065038.39449-2-shaolexi@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util')
| -rw-r--r-- | tools/perf/util/symbol.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 0fc9a5410739..35116aed74eb 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -702,6 +702,10 @@ static int map__process_kallsym_symbol(void *arg, const char *name, if (!symbol_type__filter(type)) return 0; + /* Ignore local symbols for ARM modules */ + if (name[0] == '$') + return 0; + /* * module symbols are not sorted so we add all * symbols, setting length to 0, and rely on |