From 362f9c907fd8c2be3d5c5686ea787bca25443cdc Mon Sep 17 00:00:00 2001 From: elisabeth Date: Fri, 2 Jun 2023 14:38:15 +0200 Subject: [PATCH] perf jit: Fix incorrect file name in DWARF line table Fixes an issue where an incorrect filename was added in the DWARF line table of an ELF object file when calling 'perf inject --jit' due to not checking the filename of a debug entry against the repeated name marker (/xff/0). The marker is mentioned in the tools/perf/util/jitdump.h header, which describes the jitdump binary format, and indicitates that the filename in a debug entry is the same as the previous enrty. In the function emit_lineno_info(), in the file tools/perf/util/genelf-debug.c, the debug entry filename gets compared to the previous entry filename. If they are not the same, a new filename is added to the DWARF line table. However, since there is no check against '\xff\0', in some cases '\xff\0' is inserted as the filename into the DWARF line table. This can be seen with `objdump --dwarf=line` on the ELF file after `perf inject --jit`. It also makes no source code information show up in 'perf annotate'. Signed-off-by: Elisabeth Panholzer Acked-by: Namhyung Kim Link: https://lore.kernel.org/r/20230602123815.255001-1-paniii94@gmail.com [ Fixed a trailing white space, removed a subject prefix ] Signed-off-by: Namhyung Kim --- tools/perf/util/genelf_debug.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/genelf_debug.c b/tools/perf/util/genelf_debug.c index aa5dcc56b2ac..8588b3e35e00 100644 --- a/tools/perf/util/genelf_debug.c +++ b/tools/perf/util/genelf_debug.c @@ -337,6 +337,9 @@ static void emit_lineno_info(struct buffer_ext *be, { size_t i; + /* as described in the jitdump format */ + const char repeated_name_marker[] = {'\xff', '\0'}; + /* * Machine state at start of a statement program * address = 0 @@ -363,7 +366,8 @@ static void emit_lineno_info(struct buffer_ext *be, /* * check if filename changed, if so add it */ - if (!cur_filename || strcmp(cur_filename, ent->name)) { + if ((!cur_filename || strcmp(cur_filename, ent->name)) && + strcmp(repeated_name_marker, ent->name)) { emit_lne_define_filename(be, ent->name); cur_filename = ent->name; emit_set_file(be, ++cur_file_idx);