This series adds support for the clone3 system call to the nios2 architecture. This addresses the build-time warning "warning: clone3() entry point is missing, please fix" introduced in 505d66d1abfb9 ("clone3: drop __ARCH_WANT_SYS_CLONE3 macro"). The implementation passes the relevant clone3 tests of kselftest when applied on top of next-20250815:
./run_kselftest.sh TAP version 13 1..4 # selftests: clone3: clone3 ok 1 selftests: clone3: clone3 # selftests: clone3: clone3_clear_sighand ok 2 selftests: clone3: clone3_clear_sighand # selftests: clone3: clone3_set_tid ok 3 selftests: clone3: clone3_set_tid # selftests: clone3: clone3_cap_checkpoint_restore ok 4 selftests: clone3: clone3_cap_checkpoint_restore
The series also includes a small patch to kernel/fork.c that ensures that clone_flags are passed correctly on architectures where unsigned long is insufficient to store the u64 clone_flags. It is marked as a fix for stable backporting.
As requested, in v2, this series now further tries to correct this type error throughout the whole code base. Thus, it now touches a larger number of subsystems and all architectures.
Therefore, another test was performed for ARCH=x86_64 (as a representative for 64-bit architectures). Here, the series builds cleanly without warnings on defconfig with CONFIG_SECURITY_APPARMOR=y and CONFIG_SECURITY_TOMOYO=y (to compile-check the LSM-related changes). The build further successfully passes testing/selftests/clone3 (with the patch from 20241105062948.1037011-1-zhouyuhang1010@163.com to prepare clone3_cap_checkpoint_restore for compatibility with the newer libcap version on my system).
Is there any option to further preflight check this patch series via lkp/KernelCI/etc. for a broader test across architectures, or is this degree of testing sufficient to eventually get the series merged?
N.B.: The series is not checkpatch clean right now: - include/linux/cred.h, include/linux/mnt_namespace.h: function definition arguments without identifier name - include/trace/events/task.h: space prohibited after that open parenthesis
I did not fix these warnings to keep my changes minimal and reviewable, as the issues persist throughout the files and they were not introduced by me; I only followed the existing code style and just replaced the types. If desired, I'd be happy to make the changes in a potential v3, though.
Signed-off-by: Simon Schuster schuster.simon@siemens-energy.com --- Changes in v2: - Introduce "Fixes:" and "Cc: stable@vger.kernel.org" where necessary - Factor out "Fixes:" when adapting the datatype of clone_flags for easier backports - Fix additional instances where `unsigned long` clone_flags is used - Reword commit message to make it clearer that any 32-bit arch is affected by this bug - Link to v1: https://lore.kernel.org/r/20250821-nios2-implement-clone3-v1-0-1bb24017376a@...
--- Simon Schuster (4): copy_sighand: Handle architectures where sizeof(unsigned long) < sizeof(u64) copy_process: pass clone_flags as u64 across calltree arch: copy_thread: pass clone_flags as u64 nios2: implement architecture-specific portion of sys_clone3
arch/alpha/kernel/process.c | 2 +- arch/arc/kernel/process.c | 2 +- arch/arm/kernel/process.c | 2 +- arch/arm64/kernel/process.c | 2 +- arch/csky/kernel/process.c | 2 +- arch/hexagon/kernel/process.c | 2 +- arch/loongarch/kernel/process.c | 2 +- arch/m68k/kernel/process.c | 2 +- arch/microblaze/kernel/process.c | 2 +- arch/mips/kernel/process.c | 2 +- arch/nios2/include/asm/syscalls.h | 1 + arch/nios2/include/asm/unistd.h | 2 -- arch/nios2/kernel/entry.S | 6 ++++++ arch/nios2/kernel/process.c | 2 +- arch/nios2/kernel/syscall_table.c | 1 + arch/openrisc/kernel/process.c | 2 +- arch/parisc/kernel/process.c | 2 +- arch/powerpc/kernel/process.c | 2 +- arch/riscv/kernel/process.c | 2 +- arch/s390/kernel/process.c | 2 +- arch/sh/kernel/process_32.c | 2 +- arch/sparc/kernel/process_32.c | 2 +- arch/sparc/kernel/process_64.c | 2 +- arch/um/kernel/process.c | 2 +- arch/x86/include/asm/fpu/sched.h | 2 +- arch/x86/include/asm/shstk.h | 4 ++-- arch/x86/kernel/fpu/core.c | 2 +- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/shstk.c | 2 +- arch/xtensa/kernel/process.c | 2 +- block/blk-ioc.c | 2 +- fs/namespace.c | 2 +- include/linux/cgroup.h | 4 ++-- include/linux/cred.h | 2 +- include/linux/iocontext.h | 6 +++--- include/linux/ipc_namespace.h | 4 ++-- include/linux/lsm_hook_defs.h | 2 +- include/linux/mnt_namespace.h | 2 +- include/linux/nsproxy.h | 2 +- include/linux/pid_namespace.h | 4 ++-- include/linux/rseq.h | 4 ++-- include/linux/sched/task.h | 2 +- include/linux/security.h | 4 ++-- include/linux/sem.h | 4 ++-- include/linux/time_namespace.h | 4 ++-- include/linux/uprobes.h | 4 ++-- include/linux/user_events.h | 4 ++-- include/linux/utsname.h | 4 ++-- include/net/net_namespace.h | 4 ++-- include/trace/events/task.h | 6 +++--- ipc/namespace.c | 2 +- ipc/sem.c | 2 +- kernel/cgroup/namespace.c | 2 +- kernel/cred.c | 2 +- kernel/events/uprobes.c | 2 +- kernel/fork.c | 10 +++++----- kernel/nsproxy.c | 4 ++-- kernel/pid_namespace.c | 2 +- kernel/sched/core.c | 4 ++-- kernel/sched/fair.c | 2 +- kernel/sched/sched.h | 4 ++-- kernel/time/namespace.c | 2 +- kernel/utsname.c | 2 +- net/core/net_namespace.c | 2 +- security/apparmor/lsm.c | 2 +- security/security.c | 2 +- security/selinux/hooks.c | 2 +- security/tomoyo/tomoyo.c | 2 +- 68 files changed, 95 insertions(+), 89 deletions(-) --- base-commit: 1357b2649c026b51353c84ddd32bc963e8999603 change-id: 20250818-nios2-implement-clone3-7f252c20860b
Best regards,
From: Simon Schuster schuster.simon@siemens-energy.com
With the introduction of clone3 in commit 7f192e3cd316 ("fork: add clone3") the effective bit width of clone_flags on all architectures was increased from 32-bit to 64-bit. However, the signature of the copy_* helper functions (e.g., copy_sighand) used by copy_process was not adapted.
As such, they truncate the flags on any 32-bit architectures that supports clone3 (arc, arm, csky, m68k, microblaze, mips32, openrisc, parisc32, powerpc32, riscv32, x86-32 and xtensa).
For copy_sighand with CLONE_CLEAR_SIGHAND being an actual u64 constant, this triggers an observable bug in kernel selftest clone3_clear_sighand:
if (clone_flags & CLONE_CLEAR_SIGHAND)
in function copy_sighand within fork.c will always fail given:
unsigned long /* == uint32_t */ clone_flags #define CLONE_CLEAR_SIGHAND 0x100000000ULL
This commit fixes the bug by always passing clone_flags to copy_sighand via their declared u64 type, invariant of architecture-dependent integer sizes.
Fixes: b612e5df4587 ("clone3: add CLONE_CLEAR_SIGHAND") Cc: stable@vger.kernel.org # linux-5.5+ Signed-off-by: Simon Schuster schuster.simon@siemens-energy.com Reviewed-by: Lorenzo Stoakes lorenzo.stoakes@oracle.com --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/fork.c b/kernel/fork.c index 5115be549234..82f5d52fecf1 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1599,7 +1599,7 @@ static int copy_files(unsigned long clone_flags, struct task_struct *tsk, return 0; }
-static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) +static int copy_sighand(u64 clone_flags, struct task_struct *tsk) { struct sighand_struct *sig;
On Mon, Sep 1, 2025, at 15:09, Simon Schuster via B4 Relay wrote:
This commit fixes the bug by always passing clone_flags to copy_sighand via their declared u64 type, invariant of architecture-dependent integer sizes.
Fixes: b612e5df4587 ("clone3: add CLONE_CLEAR_SIGHAND") Cc: stable@vger.kernel.org # linux-5.5+ Signed-off-by: Simon Schuster schuster.simon@siemens-energy.com Reviewed-by: Lorenzo Stoakes lorenzo.stoakes@oracle.com
Reviewed-by: Arnd Bergmann arnd@arndb.de
On 01.09.25 15:09, Simon Schuster via B4 Relay wrote:
From: Simon Schuster schuster.simon@siemens-energy.com
With the introduction of clone3 in commit 7f192e3cd316 ("fork: add clone3") the effective bit width of clone_flags on all architectures was increased from 32-bit to 64-bit. However, the signature of the copy_* helper functions (e.g., copy_sighand) used by copy_process was not adapted.
As such, they truncate the flags on any 32-bit architectures that supports clone3 (arc, arm, csky, m68k, microblaze, mips32, openrisc, parisc32, powerpc32, riscv32, x86-32 and xtensa).
For copy_sighand with CLONE_CLEAR_SIGHAND being an actual u64 constant, this triggers an observable bug in kernel selftest clone3_clear_sighand:
if (clone_flags & CLONE_CLEAR_SIGHAND)in function copy_sighand within fork.c will always fail given:
unsigned long /* == uint32_t */ clone_flags #define CLONE_CLEAR_SIGHAND 0x100000000ULLThis commit fixes the bug by always passing clone_flags to copy_sighand via their declared u64 type, invariant of architecture-dependent integer sizes.
Fixes: b612e5df4587 ("clone3: add CLONE_CLEAR_SIGHAND") Cc: stable@vger.kernel.org # linux-5.5+ Signed-off-by: Simon Schuster schuster.simon@siemens-energy.com Reviewed-by: Lorenzo Stoakes lorenzo.stoakes@oracle.com
(stripping To list)
Acked-by: David Hildenbrand david@redhat.com
On Mon, Sep 01, 2025 at 03:09:49PM +0200, Simon Schuster via B4 Relay wrote:
This series adds support for the clone3 system call to the nios2 architecture. This addresses the build-time warning "warning: clone3()
I did not expect that to happen or matter but fine.
entry point is missing, please fix" introduced in 505d66d1abfb9 ("clone3: drop __ARCH_WANT_SYS_CLONE3 macro"). The implementation passes the relevant clone3 tests of kselftest when applied on top of next-20250815:
./run_kselftest.sh TAP version 13 1..4 # selftests: clone3: clone3 ok 1 selftests: clone3: clone3 # selftests: clone3: clone3_clear_sighand ok 2 selftests: clone3: clone3_clear_sighand # selftests: clone3: clone3_set_tid ok 3 selftests: clone3: clone3_set_tid # selftests: clone3: clone3_cap_checkpoint_restore ok 4 selftests: clone3: clone3_cap_checkpoint_restore
The series also includes a small patch to kernel/fork.c that ensures that clone_flags are passed correctly on architectures where unsigned long is insufficient to store the u64 clone_flags. It is marked as a fix for stable backporting.
As requested, in v2, this series now further tries to correct this type error throughout the whole code base. Thus, it now touches a larger number of subsystems and all architectures.
I've reworked copy_thread()/copy_thread_tls() a few years ago but I don't remember why I didn't switch to a u64 for them. Probably because only CLONE_VM and CLONE_SETTLS mattered. Thanks for doing that.
Therefore, another test was performed for ARCH=x86_64 (as a representative for 64-bit architectures). Here, the series builds cleanly without warnings on defconfig with CONFIG_SECURITY_APPARMOR=y and CONFIG_SECURITY_TOMOYO=y (to compile-check the LSM-related changes). The build further successfully passes testing/selftests/clone3 (with the patch from 20241105062948.1037011-1-zhouyuhang1010@163.com to prepare clone3_cap_checkpoint_restore for compatibility with the newer libcap version on my system).
Is there any option to further preflight check this patch series via lkp/KernelCI/etc. for a broader test across architectures, or is this degree of testing sufficient to eventually get the series merged?
N.B.: The series is not checkpatch clean right now:
- include/linux/cred.h, include/linux/mnt_namespace.h: function definition arguments without identifier name
- include/trace/events/task.h: space prohibited after that open parenthesis
I did not fix these warnings to keep my changes minimal and reviewable, as the issues persist throughout the files and they were not introduced by me; I only followed the existing code style and just replaced the types. If desired, I'd be happy to make the changes in a potential v3, though.
Signed-off-by: Simon Schuster schuster.simon@siemens-energy.com
Changes in v2:
- Introduce "Fixes:" and "Cc: stable@vger.kernel.org" where necessary
- Factor out "Fixes:" when adapting the datatype of clone_flags for easier backports
- Fix additional instances where `unsigned long` clone_flags is used
- Reword commit message to make it clearer that any 32-bit arch is affected by this bug
- Link to v1: https://lore.kernel.org/r/20250821-nios2-implement-clone3-v1-0-1bb24017376a@...
Simon Schuster (4): copy_sighand: Handle architectures where sizeof(unsigned long) < sizeof(u64) copy_process: pass clone_flags as u64 across calltree arch: copy_thread: pass clone_flags as u64 nios2: implement architecture-specific portion of sys_clone3
arch/alpha/kernel/process.c | 2 +- arch/arc/kernel/process.c | 2 +- arch/arm/kernel/process.c | 2 +- arch/arm64/kernel/process.c | 2 +- arch/csky/kernel/process.c | 2 +- arch/hexagon/kernel/process.c | 2 +- arch/loongarch/kernel/process.c | 2 +- arch/m68k/kernel/process.c | 2 +- arch/microblaze/kernel/process.c | 2 +- arch/mips/kernel/process.c | 2 +- arch/nios2/include/asm/syscalls.h | 1 + arch/nios2/include/asm/unistd.h | 2 -- arch/nios2/kernel/entry.S | 6 ++++++ arch/nios2/kernel/process.c | 2 +- arch/nios2/kernel/syscall_table.c | 1 + arch/openrisc/kernel/process.c | 2 +- arch/parisc/kernel/process.c | 2 +- arch/powerpc/kernel/process.c | 2 +- arch/riscv/kernel/process.c | 2 +- arch/s390/kernel/process.c | 2 +- arch/sh/kernel/process_32.c | 2 +- arch/sparc/kernel/process_32.c | 2 +- arch/sparc/kernel/process_64.c | 2 +- arch/um/kernel/process.c | 2 +- arch/x86/include/asm/fpu/sched.h | 2 +- arch/x86/include/asm/shstk.h | 4 ++-- arch/x86/kernel/fpu/core.c | 2 +- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/shstk.c | 2 +- arch/xtensa/kernel/process.c | 2 +- block/blk-ioc.c | 2 +- fs/namespace.c | 2 +- include/linux/cgroup.h | 4 ++-- include/linux/cred.h | 2 +- include/linux/iocontext.h | 6 +++--- include/linux/ipc_namespace.h | 4 ++-- include/linux/lsm_hook_defs.h | 2 +- include/linux/mnt_namespace.h | 2 +- include/linux/nsproxy.h | 2 +- include/linux/pid_namespace.h | 4 ++-- include/linux/rseq.h | 4 ++-- include/linux/sched/task.h | 2 +- include/linux/security.h | 4 ++-- include/linux/sem.h | 4 ++-- include/linux/time_namespace.h | 4 ++-- include/linux/uprobes.h | 4 ++-- include/linux/user_events.h | 4 ++-- include/linux/utsname.h | 4 ++-- include/net/net_namespace.h | 4 ++-- include/trace/events/task.h | 6 +++--- ipc/namespace.c | 2 +- ipc/sem.c | 2 +- kernel/cgroup/namespace.c | 2 +- kernel/cred.c | 2 +- kernel/events/uprobes.c | 2 +- kernel/fork.c | 10 +++++----- kernel/nsproxy.c | 4 ++-- kernel/pid_namespace.c | 2 +- kernel/sched/core.c | 4 ++-- kernel/sched/fair.c | 2 +- kernel/sched/sched.h | 4 ++-- kernel/time/namespace.c | 2 +- kernel/utsname.c | 2 +- net/core/net_namespace.c | 2 +- security/apparmor/lsm.c | 2 +- security/security.c | 2 +- security/selinux/hooks.c | 2 +- security/tomoyo/tomoyo.c | 2 +- 68 files changed, 95 insertions(+), 89 deletions(-)
base-commit: 1357b2649c026b51353c84ddd32bc963e8999603 change-id: 20250818-nios2-implement-clone3-7f252c20860b
Best regards,
Simon Schuster schuster.simon@siemens-energy.com
On Mon, 01 Sep 2025 15:09:49 +0200, Simon Schuster wrote:
This series adds support for the clone3 system call to the nios2 architecture. This addresses the build-time warning "warning: clone3() entry point is missing, please fix" introduced in 505d66d1abfb9 ("clone3: drop __ARCH_WANT_SYS_CLONE3 macro"). The implementation passes the relevant clone3 tests of kselftest when applied on top of next-20250815:
[...]
Seems fine to me. Thanks for fixing this.
---
Applied to the kernel-6.18.clone3 branch of the vfs/vfs.git tree. Patches in the kernel-6.18.clone3 branch should appear in linux-next soon.
Please report any outstanding bugs that were missed during review in a new review to the original patch series allowing us to drop it.
It's encouraged to provide Acked-bys and Reviewed-bys even though the patch has now been applied. If possible patch trailers will be updated.
Note that commit hashes shown below are subject to change due to rebase, trailer updates or similar. If in doubt, please check the listed branch.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git branch: kernel-6.18.clone3
[1/4] copy_sighand: Handle architectures where sizeof(unsigned long) < sizeof(u64) https://git.kernel.org/vfs/vfs/c/04ff48239f46 [2/4] copy_process: pass clone_flags as u64 across calltree https://git.kernel.org/vfs/vfs/c/5b38576cb8d3 [3/4] arch: copy_thread: pass clone_flags as u64 https://git.kernel.org/vfs/vfs/c/04e760acd97f [4/4] nios2: implement architecture-specific portion of sys_clone3 https://git.kernel.org/vfs/vfs/c/d7109d2a2358
linux-stable-mirror@lists.linaro.org
-
Arnd Bergmann -
Christian Brauner -
David Hildenbrand -
Simon Schuster via B4 Relay