[PATCH] selftests/memfd: close fd in sysctl helpers

[PATCH] selftests/memfd: close fd in sysctl helpers

[zhangchujun]

The three sysctl helpers sysctl_assert_write(), sysctl_fail_write()
and sysctl_assert_equal() open /proc/sys/vm/memfd_noexec but never
close the descriptor, leaking one fd on every call.  The noexec tests
call these helpers in a loop, so the test can run out of file
descriptors on a system with a low limit.

Close the fd before returning from each helper.

Signed-off-by: zhangchujun <zhangchujun@cmss.chinamobile.com>

diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index cdab3a837624..8bdfa91d3b76 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -120,6 +120,8 @@ static void sysctl_assert_write(const char *val)
 		printf("write sysctl %s failed: %m\n", val);
 		abort();
 	}
+
+	close(fd);
 }
 
 static void sysctl_fail_write(const char *val)
@@ -136,6 +138,8 @@ static void sysctl_fail_write(const char *val)
 				val);
 		abort();
 	}
+
+	close(fd);
 }
 
 static void sysctl_assert_equal(const char *val)
@@ -153,6 +157,8 @@ static void sysctl_assert_equal(const char *val)
 		abort();
 	}
 
+	close(fd);
+
 	/* Strip trailing whitespace. */
 	p = buf;
 	while (!isspace(*p))
-- 
2.50.1.windows.1

Re: [PATCH] selftests/memfd: close fd in sysctl helpers

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential
issues to consider:
- [High] selftests/memfd: Signed-off-by trailer uses handle instead of
  real name
- [Low] selftests/memfd: missing Fixes trailers for sysctl helper fd
  leaks
--

commit f7c1cc7489dcee54b6a1302dc52c7e84f82859e6
Author: zhangchujun <zhangchujun@cmss.chinamobile.com>

> selftests/memfd: close fd in sysctl helpers
>
> The three sysctl helpers sysctl_assert_write(), sysctl_fail_write()
> and sysctl_assert_equal() open /proc/sys/vm/memfd_noexec but never
> close the descriptor, leaking one fd on every call.  The noexec tests
> call these helpers in a loop, so the test can run out of file
> descriptors on a system with a low limit.
>
> Close the fd before returning from each helper.
>
> Signed-off-by: zhangchujun <zhangchujun@cmss.chinamobile.com>

[Severity: High]
Per Documentation/process/submitting-patches.rst, the Signed-off-by trailer
and commit Author field must use a real human name rather than a single-word
account handle or username ("zhangchujun").

[Severity: Low]
Since this fixes file descriptor leaks introduced in sysctl_assert_write(),
sysctl_fail_write(), and sysctl_assert_equal(), should the commit message
include Fixes tags for the commits that added those helpers?

  Fixes: 11f75a01448f ("selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC")
  Fixes: 6469b66e3f5a ("selftests: improve vm.memfd_noexec sysctl tests")

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261113071306.1673-1-zhangchujun@cmss.chinamobile.com?part=1