diff options
| author | Ajay Kaher <[email protected]> | 2022-11-23 15:48:16 +0530 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <[email protected]> | 2022-11-24 09:55:50 -0300 |
| commit | 6f520ce17920b3cdfbd2479b3ccf27f9706219d0 (patch) | |
| tree | 89052aa9c46bbf3f218a3fa865b32192b9d6cb30 | |
| parent | 4c12f41a14d6c4dd2b4e387eaea249cee68bc01a (diff) | |
perf symbol: correction while adjusting symbol
perf doesn't provide proper symbol information for specially crafted
.debug files.
Sometimes .debug file may not have similar program header as runtime
ELF file. For example if we generate .debug file using objcopy
--only-keep-debug resulting file will not contain .text, .data and
other runtime sections. That means corresponding program headers will
have zero FileSiz and modified Offset.
Example: program header of text section of libxxx.so:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
LOAD 0x00000000003d3000 0x00000000003d3000 0x00000000003d3000
0x000000000055ae80 0x000000000055ae80 R E 0x1000
Same program header after executing:
objcopy --only-keep-debug libxxx.so libxxx.so.debug
LOAD 0x0000000000001000 0x00000000003d3000 0x00000000003d3000
0x0000000000000000 0x000000000055ae80 R E 0x1000
Offset and FileSiz have been changed.
Following formula will not provide correct value, if program header
taken from .debug file (syms_ss):
sym.st_value -= phdr.p_vaddr - phdr.p_offset;
Correct program header information is located inside runtime ELF
file (runtime_ss).
Fixes: 2d86612aacb7805f ("perf symbol: Correct address for bss symbols")
Signed-off-by: Ajay Kaher <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexey Makhalov <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Srivatsa S. Bhat <[email protected]>
Cc: Steven Rostedt (VMware) <[email protected]>
Cc: Vasavi Sirnapalli <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
| -rw-r--r-- | tools/perf/util/symbol-elf.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 647b7dff8ef3..80345695b136 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -1303,7 +1303,7 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss, (!used_opd && syms_ss->adjust_symbols)) { GElf_Phdr phdr; - if (elf_read_program_header(syms_ss->elf, + if (elf_read_program_header(runtime_ss->elf, (u64)sym.st_value, &phdr)) { pr_debug4("%s: failed to find program header for " "symbol: %s st_value: %#" PRIx64 "\n", |