[PATCH v5 9/9] perf debuginfo: Fix libdw API contract violations

[Ian Rogers <irogers@google.com>]

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
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Ian Rogers <irogers@google.com>
---
v5:
 - Added Acked-by tag.
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