kernel/linux.git/tools/testing/selftests/memfd, branch v7.2-rc1

selftests/memfd: remove unused variable 'sig' in fuse_test

2026-06-04T21:45:06+00:00

fuse_test.c: In function 'sealing_thread_fn': fuse_test.c:165:13: warning: unused variable 'sig' [-Wunused-variable] 165 | int sig, r; | ^~~ Remove unused 'sig' to fix -Wunused-variable warning. Link: https://lore.kernel.org/20260524193732.48853-3-eva.kurchatova@virtuozzo.com Signed-off-by: Konstantin Khorenko Cc: Aristeu Rozanski Cc: Shuah Khan Signed-off-by: Andrew Morton

selftests/memfd: fix -Wmaybe-uninitialized warning in memfd_test

2026-06-04T21:45:06+00:00

Patch series "selftests/memfd: fix compilation warnings". This patchset fixes warnings about unused but initialized variables, and unused dummy buffer passed to pwrite() syscall in the tests. This patch (of 2): memfd_test.c: In function 'mfd_fail_grow_write.part.0': memfd_test.c:685:13: warning: '' may be used uninitialized [-Wmaybe-uninitialized] 685 | l = pwrite(fd, buf, mfd_def_size * 8, 0); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ pwrite() is declared with attribute 'access (read_only, 2, 3)', so GCC knows it reads from the buffer. malloc() returns uninitialized memory, hence the warning. Use calloc() to zero-initialize the buffer. The actual contents don't matter here since the test verifies that pwrite() fails on a sealed memfd. Link: https://lore.kernel.org/20260524193732.48853-1-eva.kurchatova@virtuozzo.com Link: https://lore.kernel.org/20260524193732.48853-2-eva.kurchatova@virtuozzo.com Signed-off-by: Konstantin Khorenko Signed-off-by: Eva Kurchatova Cc: Aristeu Rozanski Cc: Shuah Khan Signed-off-by: Andrew Morton

selftests/memfd: use IPC semaphore instead of SIGSTOP/SIGCONT

2026-02-12T23:45:57+00:00

selftests/memfd: use IPC semaphore instead of SIGSTOP/SIGCONT In order to synchronize new processes to test inheritance of memfd_noexec sysctl, memfd_test sets up the sysctl with a value before creating the new process. The new process then sends itself a SIGSTOP in order to wait for the parent to flip the sysctl value and send a SIGCONT signal. This would work as intended if it wasn't the fact that the new process is being created with CLONE_NEWPID, which creates a new PID namespace and the new process has PID 1 in this namespace. There're restrictions on sending signals to PID 1 and, although it's relaxed for other than root PID namespace, it's biting us here. In this specific case the SIGSTOP sent by the new process is ignored (no error to kill() is returned) and it never stops its execution. This is usually not noticiable as the parent usually manages to set the new sysctl value before the child has a chance to run and the test succeeds. But if you run the test in a loop, it eventually reproduces: while [ 1 ]; do ./memfd_test >log 2>&1 || break; done; cat log So this patch replaces the SIGSTOP/SIGCONT synchronization with IPC semaphore. Link: https://lkml.kernel.org/r/a7776389-b3d6-4b18-b438-0b0e3ed1fd3b@work Fixes: 6469b66e3f5a ("selftests: improve vm.memfd_noexec sysctl tests") Signed-off-by: Aristeu Rozanski Cc: Aleksa Sarai Cc: Shuah Khan Cc: liuye Cc: Lorenzo Stoakes Signed-off-by: Andrew Morton

selftests/memfd/memfd_test: fix possible NULL pointer dereference

2025-01-26T04:22:44+00:00

If `name' is NULL, a NULL pointer may be accessed in printf. Link: https://lkml.kernel.org/r/20250114032115.58638-1-liuye@kylinos.cn Signed-off-by: liuye Reviewed-by: Lorenzo Stoakes Cc: Greg Thelen Cc: "Isaac J. Manjarres" Cc: Jeff Xu Cc: Saurav Shah Cc: Shuah Khan (Samsung OSG) Signed-off-by: Andrew Morton

selftests/memfd: add test for mapping write-sealed memfd read-only

2024-12-31T01:59:06+00:00

Now we have reinstated the ability to map F_SEAL_WRITE mappings read-only, assert that we are able to do this in a test to ensure that we do not regress this again. Link: https://lkml.kernel.org/r/a6377ec470b14c0539b4600cf8fa24bf2e4858ae.1732804776.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Jann Horn Cc: Julian Orth Cc: Liam R. Howlett Cc: Linus Torvalds Cc: Shuah Khan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

selftests/memfd: run sysctl tests when PID namespace support is enabled

2024-12-19T03:04:41+00:00

The sysctl tests for vm.memfd_noexec rely on the kernel to support PID namespaces (i.e. the kernel is built with CONFIG_PID_NS=y). If the kernel the test runs on does not support PID namespaces, the first sysctl test will fail when attempting to spawn a new thread in a new PID namespace, abort the test, preventing the remaining tests from being run. This is not desirable, as not all kernels need PID namespaces, but can still use the other features provided by memfd. Therefore, only run the sysctl tests if the kernel supports PID namespaces. Otherwise, skip those tests and emit an informative message to let the user know why the sysctl tests are not being run. Link: https://lkml.kernel.org/r/20241205192943.3228757-1-isaacmanjarres@google.com Fixes: 11f75a01448f ("selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC") Signed-off-by: Isaac J. Manjarres Reviewed-by: Jeff Xu Cc: Suren Baghdasaryan Cc: Kalesh Singh Cc: [6.6+] Signed-off-by: Andrew Morton

selftests/memfd: fix spelling mistakes

2024-05-07T17:36:59+00:00

Fix spelling mistakes in the comments. Link: https://lkml.kernel.org/r/20240501231317.24648-1-sauravshah.31@gmail.com Signed-off-by: Saurav Shah Cc: Aleksa Sarai Cc: Greg Thelen Cc: Jeff Xu Cc: Shuah Khan Signed-off-by: Andrew Morton

selftests/memfd: delete unused declarations

2024-02-22T18:24:38+00:00

Commit 32d118ad50a5 ("selftests/memfd: add tests for F_SEAL_EXEC"): - added several unused 'nbytes' local variables Commit 6469b66e3f5a ("selftests: improve vm.memfd_noexec sysctl tests"): - orphaned 'newpid_thread_fn2()' forward declaration - orphaned 'join_newpid_thread()' forward declaration - added unused 'pid' local in sysctl_simple_child() - orphaned 'fd' local in sysctl_simple_child() - added unused 'fd' in sysctl_nested_child() Delete the unused locals and forward declarations. Link: https://lkml.kernel.org/r/20240118095057.677544-1-gthelen@google.com Signed-off-by: Greg Thelen Cc: Aleksa Sarai Cc: Daniel Verkamp Cc: Jeff Xu Cc: Kees Cook Cc: Shuah Khan Signed-off-by: Andrew Morton

selftests: improve vm.memfd_noexec sysctl tests

2023-08-21T20:38:00+00:00

This adds proper tests for the nesting functionality of vm.memfd_noexec as well as some minor cleanups to spawn_*_thread(). Link: https://lkml.kernel.org/r/20230814-memfd-vm-noexec-uapi-fixes-v2-5-7ff9e3e10ba6@cyphar.com Signed-off-by: Aleksa Sarai Cc: Christian Brauner Cc: Daniel Verkamp Cc: Dominique Martinet Cc: Jeff Xu Cc: Kees Cook Cc: Shuah Khan Signed-off-by: Andrew Morton

memfd: do not -EACCES old memfd_create() users with vm.memfd_noexec=2

2023-08-21T20:37:59+00:00

Given the difficulty of auditing all of userspace to figure out whether every memfd_create() user has switched to passing MFD_EXEC and MFD_NOEXEC_SEAL flags, it seems far less distruptive to make it possible for older programs that don't make use of executable memfds to run under vm.memfd_noexec=2. Otherwise, a small dependency change can result in spurious errors. For programs that don't use executable memfds, passing MFD_NOEXEC_SEAL is functionally a no-op and thus having the same In addition, every failure under vm.memfd_noexec=2 needs to print to the kernel log so that userspace can figure out where the error came from. The concerns about pr_warn_ratelimited() spam that caused the switch to pr_warn_once()[1,2] do not apply to the vm.memfd_noexec=2 case. This is a user-visible API change, but as it allows programs to do something that would be blocked before, and the sysctl itself was broken and recently released, it seems unlikely this will cause any issues. [1]: https://lore.kernel.org/Y5yS8wCnuYGLHMj4@x1n/ [2]: https://lore.kernel.org/202212161233.85C9783FB@keescook/ Link: https://lkml.kernel.org/r/20230814-memfd-vm-noexec-uapi-fixes-v2-2-7ff9e3e10ba6@cyphar.com Fixes: 105ff5339f49 ("mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC") Signed-off-by: Aleksa Sarai Cc: Dominique Martinet Cc: Christian Brauner Cc: Daniel Verkamp Cc: Jeff Xu Cc: Kees Cook Cc: Shuah Khan Cc: Signed-off-by: Andrew Morton