Commit 2cc4d1c5eab1 ("tests/check-block: Skip iotests when sanitizers
are enabled") changed iotests to skip when sanitizers are enabled.
The rationale is that AddressSanitizer emits warnings and reports leaks,
which results in test breakage. Later, sanitizers that are enabled for
production environments (safe-stack and cfi-icall) were exempted.

However, this approach has a few problems.

- It requires rebuild to disable sanitizers if the existing build has
  them enabled.
- It disables other useful non-production sanitizers.
- The exemption of safe-stack and cfi-icall is not correctly
  implemented, so qemu-iotests are incorrectly enabled whenever either
  safe-stack or cfi-icall is enabled *and*, even if there is another
  sanitizer like AddressSanitizer.

To solve these problems, direct AddressSanitizer warnings to separate
files to avoid changing the test results, and selectively disable
leak detection at runtime instead of requiring to disable all
sanitizers at buildtime.

Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
---
 tests/qemu-iotests/meson.build   |  8 --------
 tests/qemu-iotests/testrunner.py | 12 ++++++++++++
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/tests/qemu-iotests/meson.build b/tests/qemu-iotests/meson.build
index fad340ad5957..56b04468274a 100644
--- a/tests/qemu-iotests/meson.build
+++ b/tests/qemu-iotests/meson.build
@@ -2,14 +2,6 @@ if not have_tools or host_os == 'windows'
   subdir_done()
 endif
 
-foreach cflag: qemu_ldflags
-  if cflag.startswith('-fsanitize') and \
-     not cflag.contains('safe-stack') and not cflag.contains('cfi-icall')
-    message('Sanitizers are enabled ==> Disabled the qemu-iotests.')
-    subdir_done()
-  endif
-endforeach
-
 bash = find_program('bash', required: false, version: '>= 4.0')
 if not bash.found()
   message('bash >= v4.0 not available ==> Disabled the qemu-iotests.')
diff --git a/tests/qemu-iotests/testrunner.py b/tests/qemu-iotests/testrunner.py
index 14cc8492f9fb..e2a365899414 100644
--- a/tests/qemu-iotests/testrunner.py
+++ b/tests/qemu-iotests/testrunner.py
@@ -263,10 +263,21 @@ def do_run_test(self, test: str) -> TestResult:
             Path(env[d]).mkdir(parents=True, exist_ok=True)
 
         test_dir = env['TEST_DIR']
+        f_asan = Path(test_dir, f_test.name + '.out.asan')
         f_bad = Path(test_dir, f_test.name + '.out.bad')
         f_notrun = Path(test_dir, f_test.name + '.notrun')
         f_casenotrun = Path(test_dir, f_test.name + '.casenotrun')
 
+        env['ASAN_OPTIONS'] = f'detect_leaks=0:log_path={f_asan}'
+
+        def unlink_asan():
+            with os.scandir(test_dir) as it:
+                for entry in it:
+                    if entry.name.startswith(f_asan.name):
+                        os.unlink(entry)
+
+        unlink_asan()
+
         for p in (f_notrun, f_casenotrun):
             silent_unlink(p)
 
@@ -312,6 +323,7 @@ def do_run_test(self, test: str) -> TestResult:
                               description=f'output mismatch (see {f_bad})',
                               diff=diff, casenotrun=casenotrun)
         else:
+            unlink_asan()
             f_bad.unlink()
             return TestResult(status='pass', elapsed=elapsed,
                               casenotrun=casenotrun)

-- 
2.51.0

On 23/10/25 10:10, Akihiko Odaki wrote:
> Commit 2cc4d1c5eab1 ("tests/check-block: Skip iotests when sanitizers
> are enabled") changed iotests to skip when sanitizers are enabled.
> The rationale is that AddressSanitizer emits warnings and reports leaks,
> which results in test breakage. Later, sanitizers that are enabled for
> production environments (safe-stack and cfi-icall) were exempted.
> 
> However, this approach has a few problems.
> 
> - It requires rebuild to disable sanitizers if the existing build has
>    them enabled.
> - It disables other useful non-production sanitizers.
> - The exemption of safe-stack and cfi-icall is not correctly
>    implemented, so qemu-iotests are incorrectly enabled whenever either
>    safe-stack or cfi-icall is enabled *and*, even if there is another
>    sanitizer like AddressSanitizer.
> 
> To solve these problems, direct AddressSanitizer warnings to separate
> files to avoid changing the test results, and selectively disable
> leak detection at runtime instead of requiring to disable all
> sanitizers at buildtime.
> 
> Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
> ---
>   tests/qemu-iotests/meson.build   |  8 --------
>   tests/qemu-iotests/testrunner.py | 12 ++++++++++++
>   2 files changed, 12 insertions(+), 8 deletions(-)

Nice.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>