From: Jiri Olsa jolsa@redhat.com
[ Upstream commit 59a17706915fe5ea6f711e1f92d4fb706bce07fe ]
When perf is built with the annobin plugin (RHEL8 build) extra symbols are added to its binary:
# nm perf | grep annobin | head -10 0000000000241100 t .annobin_annotate.c 0000000000326490 t .annobin_annotate.c 0000000000249255 t .annobin_annotate.c_end 00000000003283a8 t .annobin_annotate.c_end 00000000001bce18 t .annobin_annotate.c_end.hot 00000000001bce18 t .annobin_annotate.c_end.hot 00000000001bc3e2 t .annobin_annotate.c_end.unlikely 00000000001bc400 t .annobin_annotate.c_end.unlikely 00000000001bce18 t .annobin_annotate.c.hot 00000000001bce18 t .annobin_annotate.c.hot ...
Those symbols have no use for report or annotation and should be skipped. Moreover they interfere with the DWARF unwind test on the PPC arch, where they are mixed with checked symbols and then the test fails:
# perf test dwarf -v 59: Test dwarf unwind : --- start --- test child forked, pid 8515 unwind: .annobin_dwarf_unwind.c:ip = 0x10dba40dc (0x2740dc) ... got: .annobin_dwarf_unwind.c 0x10dba40dc, expecting test__arch_unwind_sample unwind: failed with 'no error'
The annobin symbols are defined as NOTYPE/LOCAL/HIDDEN:
# readelf -s ./perf | grep annobin | head -1 40: 00000000001bce4f 0 NOTYPE LOCAL HIDDEN 13 .annobin_init.c
They can still pass the check for the label symbol. Adding check for HIDDEN and INTERNAL (as suggested by Nick below) visibility and filter out such symbols.
Just to be awkward, if you are going to ignore STV_HIDDEN symbols then you should probably also ignore STV_INTERNAL ones as well... Annobin does not generate them, but you never know, one day some other tool might create some.
Signed-off-by: Jiri Olsa jolsa@kernel.org Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Michael Petlan mpetlan@redhat.com Cc: Namhyung Kim namhyung@kernel.org Cc: Nick Clifton nickc@redhat.com Cc: Peter Zijlstra peterz@infradead.org Link: http://lkml.kernel.org/r/20190128133526.GD15461@krava Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/symbol-elf.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 66a84d5846c88..03cb8c6d620aa 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -87,6 +87,11 @@ static inline uint8_t elf_sym__type(const GElf_Sym *sym) return GELF_ST_TYPE(sym->st_info); }
+static inline uint8_t elf_sym__visibility(const GElf_Sym *sym) +{ + return GELF_ST_VISIBILITY(sym->st_other); +} + #ifndef STT_GNU_IFUNC #define STT_GNU_IFUNC 10 #endif @@ -111,7 +116,9 @@ static inline int elf_sym__is_label(const GElf_Sym *sym) return elf_sym__type(sym) == STT_NOTYPE && sym->st_name != 0 && sym->st_shndx != SHN_UNDEF && - sym->st_shndx != SHN_ABS; + sym->st_shndx != SHN_ABS && + elf_sym__visibility(sym) != STV_HIDDEN && + elf_sym__visibility(sym) != STV_INTERNAL; }
static bool elf_sym__filter(GElf_Sym *sym)