diff options
| author | Lexi Shao <[email protected]> | 2021-10-29 14:50:37 +0800 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <[email protected]> | 2021-11-07 12:27:38 -0300 |
| commit | 1a86f4ba5cf1c19b55a12be8e5e9235a23921f8d (patch) | |
| tree | 4e8370bf59e5a84755f1830059bdab4435323928 | |
| parent | eb39bf325631f9ae185abd16281079b7b9858737 (diff) | |
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 $a symbols in /proc/kallsyms which
share the same addresses with the actual module symbols and confuses
perf when resolving symbols.
After this patch, the module symbol name is printed:
c0f2e39c schedule_hrtimeout+0x14 ([kernel.kallsyms])
bf4a66d8 test_func+0x78 ([test_module])
c0a4f5f4 kthread+0x15c ([kernel.kallsyms])
c0a001f8 ret_from_fork+0x14 ([kernel.kallsyms])
Reviewed-by: James Clark <[email protected]>
Signed-off-by: Lexi Shao <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Fastabend <[email protected]>
Cc: KP Singh <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: QiuXi <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Wangbing <[email protected]>
Cc: Xiaoming Ni <[email protected]>
Cc: Yonghong Song <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
| -rw-r--r-- | tools/perf/util/symbol.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 0fc9a5410739..35116aed74eb 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -702,6 +702,10 @@ static int map__process_kallsym_symbol(void *arg, const char *name, if (!symbol_type__filter(type)) return 0; + /* Ignore local symbols for ARM modules */ + if (name[0] == '$') + return 0; + /* * module symbols are not sorted so we add all * symbols, setting length to 0, and rely on |