[PATCH v1] perf test code-reading: Fix duplicate kernel maps and machine leak

[PATCH v1] perf test code-reading: Fix duplicate kernel maps and machine leak

[Ian Rogers]

In do_test_code_reading(), machine__new_host(&host_env) already calls
machine__create_kernel_maps(machine). Calling
machine__create_kernel_maps(machine) a second time immediately
afterwards duplicates all kernel module maps in machine->kmaps, causing
dso__load_kcore()'s module validation (do_validate_kcore_modules()) to
fail and fall back to /proc/kallsyms.

Furthermore, when try_kcore is true and !have_kcore, returning
TEST_CODE_READING_NO_KCORE directly bypasses out_err, leaking the entire
struct machine, its kernel/module maps and DSOs, all kallsyms symbols,
and host_env.

Remove the redundant machine__create_kernel_maps() call, check for
!machine after machine__new_host(), and jump to out_err when returning
TEST_CODE_READING_NO_KCORE.

Fixes: 0fd4008ed755 ("perf test: Use machine__new_host in mmap thread code reading test")
Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/code-reading.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
index f0e8ea8754ef..c50b526f44fb 100644
--- a/tools/perf/tests/code-reading.c
+++ b/tools/perf/tests/code-reading.c
@@ -716,10 +716,8 @@ static int do_test_code_reading(bool try_kcore)
 
 	perf_env__init(&host_env);
 	machine = machine__new_host(&host_env);
-
-	ret = machine__create_kernel_maps(machine);
-	if (ret < 0) {
-		pr_debug("machine__create_kernel_maps failed\n");
+	if (!machine) {
+		pr_debug("machine__new_host failed\n");
 		goto out_err;
 	}
 
@@ -739,8 +737,10 @@ static int do_test_code_reading(bool try_kcore)
 	have_kcore = dso__is_kcore(dso);
 
 	/* 2nd time through we just try kcore */
-	if (try_kcore && !have_kcore)
-		return TEST_CODE_READING_NO_KCORE;
+	if (try_kcore && !have_kcore) {
+		err = TEST_CODE_READING_NO_KCORE;
+		goto out_err;
+	}
 
 	/* No point getting kernel events if there is no kernel object */
 	if (!have_vmlinux && !have_kcore)
-- 
2.56.0.rc1.315.gc6ed9934b7-goog

Re: [PATCH v1] perf test code-reading: Fix duplicate kernel maps and machine leak

[sashiko-bot]

> In do_test_code_reading(), machine__new_host(&host_env) already calls
> machine__create_kernel_maps(machine). Calling
> machine__create_kernel_maps(machine) a second time immediately
> afterwards duplicates all kernel module maps in machine->kmaps, causing
> dso__load_kcore()'s module validation (do_validate_kcore_modules()) to
> fail and fall back to /proc/kallsyms.
> 
> Furthermore, when try_kcore is true and !have_kcore, returning
> TEST_CODE_READING_NO_KCORE directly bypasses out_err, leaking the entire
> struct machine, its kernel/module maps and DSOs, all kallsyms symbols,
> and host_env.
> 
> Remove the redundant machine__create_kernel_maps() call, check for
> !machine after machine__new_host(), and jump to out_err when returning
> TEST_CODE_READING_NO_KCORE.
> 
> Fixes: 0fd4008ed755 ("perf test: Use machine__new_host in mmap thread code reading test")
> Assisted-by: Antigravity:gemini-3.1-pro
> Signed-off-by: Ian Rogers <irogers@google.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260928075517.3057621-1-irogers@google.com?part=1

Re: [PATCH v1] perf test code-reading: Fix duplicate kernel maps and machine leak

[Arnaldo Carvalho de Melo]

On Mon, Sep 28, 2026 at 12:55:17AM -0700, Ian Rogers wrote:
> Furthermore, when try_kcore is true and !have_kcore, returning
> TEST_CODE_READING_NO_KCORE directly bypasses out_err, leaking the entire
> struct machine, its kernel/module maps and DSOs, all kallsyms symbols,
> and host_env.
> 
> Remove the redundant machine__create_kernel_maps() call, check for
> !machine after machine__new_host(), and jump to out_err when returning
> TEST_CODE_READING_NO_KCORE.
 
> Fixes: 0fd4008ed755 ("perf test: Use machine__new_host in mmap thread code reading test")
> Assisted-by: Antigravity:gemini-3.1-pro

Thanks, applied to perf-tools-next, for v7.4.

- Arnaldo