[LTP] [PATCH] Update clone3 wrapper signature

[Chris Wailes]

Would it be better/easier for me to submit this through GitHub?

- Chris

On Wed, Mar 4, 2026 at 1:33 PM Chris Wailes <chriswailes@google.com> wrote:

> Apologies for the delayed response.  Please find my updated patch below.
>
> ---
>
> From 50564557a72df12d500997dd145cc5376edd8063 Mon Sep 17 00:00:00 2001
> From: Chris Wailes <chriswailes@google.com>
> Date: Fri, 14 Nov 2025 13:56:39 -0800
> Subject: [PATCH] Update clone3 wrapper signature
>
> This CL adds the `ltp_clone3_raw` wrapper for direct testing of the
> syscall, conditionally defines `clone_args_minimal`, and adds a
> `ltp_clone3` wrapper for libc implementations that provide `clone3`.
>
> Signed-off-by: Chris Wailes <chriswailes@google.com>
> ---
>  include/lapi/sched.h                        | 32 +++++++++++++++------
>  testcases/kernel/syscalls/clone3/clone301.c |  2 +-
>  testcases/kernel/syscalls/clone3/clone302.c |  2 +-
>  3 files changed, 25 insertions(+), 11 deletions(-)
>
> diff --git a/include/lapi/sched.h b/include/lapi/sched.h
> index 0ffe44641..c0fa8dd47 100644
> --- a/include/lapi/sched.h
> +++ b/include/lapi/sched.h
> @@ -49,9 +49,13 @@ static inline int sched_getattr(pid_t pid, struct
> sched_attr *attr,
>  # define SCHED_ATTR_SIZE_VER0 48 /* sizeof first published struct */
>  #endif
>
> -#ifndef HAVE_CLONE3
> -#ifndef HAVE_STRUCT_CLONE_ARGS
> -struct clone_args {
> +static inline int ltp_clone3_raw(struct clone_args *args, size_t size)
> +{
> + return tst_syscall(__NR_clone3, args, size);
> +}
> +
> +#ifndef HAVE_STRUCT_CLONE_ARGS_MINIMAL
> +struct clone_args_minimal {
>   uint64_t __attribute__((aligned(8))) flags;
>   uint64_t __attribute__((aligned(8))) pidfd;
>   uint64_t __attribute__((aligned(8))) child_tid;
> @@ -60,13 +64,12 @@ struct clone_args {
>   uint64_t __attribute__((aligned(8))) stack;
>   uint64_t __attribute__((aligned(8))) stack_size;
>   uint64_t __attribute__((aligned(8))) tls;
> - uint64_t __attribute__((aligned(8))) set_tid;
> - uint64_t __attribute__((aligned(8))) set_tid_size;
> - uint64_t __attribute__((aligned(8))) cgroup;
>  };
>  #endif
>
> -struct clone_args_minimal {
> +#ifndef HAVE_CLONE3
> +#ifndef HAVE_STRUCT_CLONE_ARGS
> +struct clone_args {
>   uint64_t __attribute__((aligned(8))) flags;
>   uint64_t __attribute__((aligned(8))) pidfd;
>   uint64_t __attribute__((aligned(8))) child_tid;
> @@ -75,11 +78,22 @@ struct clone_args_minimal {
>   uint64_t __attribute__((aligned(8))) stack;
>   uint64_t __attribute__((aligned(8))) stack_size;
>   uint64_t __attribute__((aligned(8))) tls;
> + uint64_t __attribute__((aligned(8))) set_tid;
> + uint64_t __attribute__((aligned(8))) set_tid_size;
> + uint64_t __attribute__((aligned(8))) cgroup;
>  };
> +#endif
>
> -static inline int clone3(struct clone_args *args, size_t size)
> +int ltp_clone3(struct clone_args *cl_args, size_t size,
> +               int (*fn)(void *), void *arg) {
> + return clone3(cl_args, size, fn, arg);
> +}
> +#else
> +
> +static inline int ltp_clone3(struct clone_args *cl_args, size_t size,
> +                             int (*fn)(void *), void *arg)
>  {
> - return tst_syscall(__NR_clone3, args, size);
> + return -1;
>  }
>  #endif
>
> diff --git a/testcases/kernel/syscalls/clone3/clone301.c
> b/testcases/kernel/syscalls/clone3/clone301.c
> index deed30b9f..58fc1702e 100644
> --- a/testcases/kernel/syscalls/clone3/clone301.c
> +++ b/testcases/kernel/syscalls/clone3/clone301.c
> @@ -123,7 +123,7 @@ static void run(unsigned int n)
>   parent_received_signal = 0;
>   SAFE_SIGACTION(tc->exit_signal, &psig_action, NULL);
>
> - TEST(pid = clone3(args, sizeof(*args)));
> + TEST(pid = ltp_clone3_raw(args, sizeof(*args)));
>   if (pid < 0) {
>   tst_res(TFAIL | TTERRNO, "clone3() failed (%d)", n);
>   return;
> diff --git a/testcases/kernel/syscalls/clone3/clone302.c
> b/testcases/kernel/syscalls/clone3/clone302.c
> index 9e98f1954..883112183 100644
> --- a/testcases/kernel/syscalls/clone3/clone302.c
> +++ b/testcases/kernel/syscalls/clone3/clone302.c
> @@ -83,7 +83,7 @@ static void run(unsigned int n)
>   args->tls = tc->tls;
>   }
>
> - TEST(clone3(args, tc->size));
> + TEST(ltp_clone3_raw(args, tc->size));
>
>   if (!TST_RET)
>   exit(EXIT_SUCCESS);
> --
> 2.53.0.473.g4a7958ca14-goog
>
> On Wed, Dec 17, 2025 at 1:43 AM Li Wang <liwang@redhat.com> wrote:
>
>>
>>
>> On Wed, Dec 17, 2025 at 3:58 PM Anrea Cervesato via ltp <
>> ltp@lists.linux.it> wrote:
>>
>>> Hi Chris,
>>>
>>> On 12/16/25 6:50 PM, Chris Wailes wrote:
>>> > Andrea,
>>> >
>>> > Thanks for reviewing the change.  We're currently adding a `clone3`
>>> > wrapper to Android's BIONIC libc implementation. Additionally, this is
>>> > the signature used for `glibc`'s `__clone3`
>>> > <
>>> https://github.com/bminor/glibc/blob/ded9c1e525f2d69a81e61c34c29077fed7df658c/include/clone_internal.h
>>> >.
>>> >
>>> > - Chris
>>>
>>> At this point, I think we should just adopt tst_clone() instead of
>>> clone3() fallback.
>>>
>>
>> Perhaps a simple approach is to define a raw system call for clone3
>> and use it in all existing tests, and then add new tests if we plan to
>> test the libc-like clone3 wrapper (with four args).
>>
>> Otherwise the new added 'NULL, NULL' arguments for current hacked
>> clone3 makes no sense.
>>
>> static inline int ltp_clone3_raw(struct clone_args *args, size_t size)
>> {
>>     return tst_syscall(__NR_clone3, args, size);
>> }
>>
>> #ifdef HAVE_CLONE3_WRAPPER
>> int ltp_clone3(struct clone_args *cl_args, size_t size,
>>                int (*fn)(void *), void *arg);
>> #else
>> static inline int ltp_clone3(struct clone_args *cl_args, size_t size,
>>                             int (*fn)(void *), void *arg)
>> {
>>     return -1;
>> }
>> #endif
>>
>> Btw, the above changes should be put in lapi/sched.h if we decide go this.
>>
>>
>> --
>> Regards,
>> Li Wang
>>
>