Re: [PATCH v4 6/6] perf debuginfo: Fix libdw API contract violations

Namhyung Kim
2026-05-03T23:54:51Z

On Sun, May 03, 2026 at 10:10:32AM -0700, Ian Rogers wrote:
> Check return value of `dwfl_report_end` during offline initialization.
> Validate `dwfl_module_relocation_info` result before passing to `strcmp`
> to avoid potential segmentation faults.
>
> Additionally:
> - Fix a file descriptor leak in `debuginfo__init_offline_dwarf()` when
> `dwfl_report_offline()` or subsequent setup calls fail.
>
> Fixes: 6f1b6291cf73 ("perf tools: Add util/debuginfo.[ch] files")
> Assisted-by: Gemini-CLI:Google Gemini 3
> Signed-off-by: Ian Rogers <irogers@google.com>

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung

> ---
> v4:
> - Fix file descriptor leaks in debuginfo init paths.
> ---
> tools/perf/util/debuginfo.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/debuginfo.c b/tools/perf/util/debuginfo.c
> index 0e35c13abd04..84a78b30ceac 100644
> --- a/tools/perf/util/debuginfo.c
> +++ b/tools/perf/util/debuginfo.c
> @@ -42,6 +42,7 @@ static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
> {
> GElf_Addr dummy;
> int fd;
> + bool fd_consumed = false;
>
> fd = open(path, O_RDONLY);
> if (fd < 0)
> @@ -55,6 +56,7 @@ static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
> dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
> if (!dbg->mod)
> goto error;
> + fd_consumed = true;
>
> dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
> if (!dbg->dbg)
> @@ -62,13 +64,14 @@ static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
>
> dwfl_module_build_id(dbg->mod, &dbg->build_id, &dummy);
>
> - dwfl_report_end(dbg->dwfl, NULL, NULL);
> + if (dwfl_report_end(dbg->dwfl, NULL, NULL) != 0)
> + goto error;
>
> return 0;
> error:
> if (dbg->dwfl)
> dwfl_end(dbg->dwfl);
> - else
> + if (!fd_consumed)
> close(fd);
> memset(dbg, 0, sizeof(*dbg));
>
> @@ -167,7 +170,7 @@ int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
> /* Search the relocation related .text section */
> for (i = 0; i < n; i++) {
> p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
> - if (strcmp(p, ".text") == 0) {
> + if (p && strcmp(p, ".text") == 0) {
> /* OK, get the section header */
> scn = elf_getscn(elf, shndx);
> if (!scn)
> --
> 2.54.0.545.g6539524ca2-goog
>