From: Georg Müller georgmueller@gmx.net
commit c66e1c68c13b872505f25ab641c44b77313ee7fe upstream.
After switching from dwarf_decl_file() to die_get_decl_file(), it is not possible to add probes for certain functions:
$ perf probe -x /usr/lib/systemd/systemd-logind match_unit_removed A function DIE doesn't have decl_line. Maybe broken DWARF? A function DIE doesn't have decl_line. Maybe broken DWARF? Probe point 'match_unit_removed' not found. Error: Failed to add events.
The problem is that die_get_decl_file() uses the wrong CU to search for the file. elfutils commit e1db5cdc9f has some good explanation for this:
dwarf_decl_file uses dwarf_attr_integrate to get the DW_AT_decl_file attribute. This means the attribute might come from a different DIE in a different CU. If so, we need to use the CU associated with the attribute, not the original DIE, to resolve the file name.
This patch uses the same source of information as elfutils: use attribute DW_AT_decl_file and use this CU to search for the file.
Fixes: dc9a5d2ccd5c823c ("perf probe: Fix to get declared file name from clang DWARF5") Signed-off-by: Georg Müller georgmueller@gmx.net Acked-by: Masami Hiramatsu (Google) mhiramat@kernel.org Cc: Adrian Hunter adrian.hunter@intel.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Ian Rogers irogers@google.com Cc: Ingo Molnar mingo@redhat.com Cc: Jiri Olsa jolsa@kernel.org Cc: Mark Rutland mark.rutland@arm.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: regressions@lists.linux.dev Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230628084551.1860532-6-georgmueller@gmx.net Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/perf/util/dwarf-aux.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -478,8 +478,10 @@ static const char *die_get_file_name(Dwa { Dwarf_Die cu_die; Dwarf_Files *files; + Dwarf_Attribute attr_mem;
- if (idx < 0 || !dwarf_diecu(dw_die, &cu_die, NULL, NULL) || + if (idx < 0 || !dwarf_attr_integrate(dw_die, DW_AT_decl_file, &attr_mem) || + !dwarf_cu_die(attr_mem.cu, &cu_die, NULL, NULL, NULL, NULL, NULL, NULL) || dwarf_getsrcfiles(&cu_die, &files, NULL) != 0) return NULL;