Re: [LTP] [PATCH v5] clone3: Add clone3's clone_args cgroup

[Richard Palethorpe <rpalethorpe@suse.de>]

Hello,

Wei Gao via ltp <ltp@lists.linux.it> writes:

> Signed-off-by: Wei Gao <wegao@suse.com>
> ---
>  include/lapi/sched.h                        |   8 ++
>  include/tst_cgroup.h                        |   4 +
>  include/tst_clone.h                         |   1 +
>  lib/tst_cgroup.c                            |   9 ++
>  lib/tst_clone.c                             |   1 +
>  runtest/syscalls                            |   1 +
>  testcases/kernel/syscalls/clone3/.gitignore |   1 +
>  testcases/kernel/syscalls/clone3/clone303.c | 101 ++++++++++++++++++++
>  8 files changed, 126 insertions(+)
>  create mode 100644 testcases/kernel/syscalls/clone3/clone303.c
>
> diff --git a/include/lapi/sched.h b/include/lapi/sched.h
> index 1065665d1..ac766efc5 100644
> --- a/include/lapi/sched.h
> +++ b/include/lapi/sched.h
> @@ -13,6 +13,7 @@
>  #include <inttypes.h>
>  #include "config.h"
>  #include "lapi/syscalls.h"
> +#include "lapi/sched.h"
>  
>  struct sched_attr {
>  	uint32_t size;
> @@ -54,6 +55,9 @@ 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;
>  };
>  
>  static inline int clone3(struct clone_args *args, size_t size)
> @@ -133,4 +137,8 @@ static inline int getcpu(unsigned *cpu, unsigned *node)
>  # define CLONE_NEWTIME		0x00000080
>  #endif
>  
> +#ifndef CLONE_INTO_CGROUP
> +# define CLONE_INTO_CGROUP 0x200000000ULL
> +#endif
> +
>  #endif /* LAPI_SCHED_H__ */
> diff --git a/include/tst_cgroup.h b/include/tst_cgroup.h
> index 2826ddad1..be14d07c6 100644
> --- a/include/tst_cgroup.h
> +++ b/include/tst_cgroup.h
> @@ -157,6 +157,10 @@ const char *
>  tst_cg_group_name(const struct tst_cg_group *const cg)
>  		      __attribute__ ((nonnull, warn_unused_result));
>  
> +/* This call returns a fd pointing to a v2 directory */
> +int tst_cg_group_unified_dir_fd(const struct tst_cg_group *const cg)
> +		      __attribute__ ((nonnull, warn_unused_result));
> +
>  /* Remove a descendant CGroup */
>  struct tst_cg_group *
>  tst_cg_group_rm(struct tst_cg_group *const cg)
> diff --git a/include/tst_clone.h b/include/tst_clone.h
> index 9ffdc68d1..7b278dfa7 100644
> --- a/include/tst_clone.h
> +++ b/include/tst_clone.h
> @@ -11,6 +11,7 @@
>  struct tst_clone_args {
>  	uint64_t flags;
>  	uint64_t exit_signal;
> +	uint64_t cgroup;

This is not used in the test being added so I will not merge it because
I don't want to do any more work than necessary (I would still merge the
rest of the test, but there is another issue below). The reason is
because it may cause some test which does use tst_clone_args to fail
because it increases the struct size. If some other test does not
initialise the members correctly we may start sending uninitialised data
to the kernel.

In general I don't want to add anything which isn't immediately
necessary without having to think about any potential problems it could
cause.

>  };
>  
>  /* clone3 with fallbacks to clone when possible. Be aware that it
> diff --git a/lib/tst_cgroup.c b/lib/tst_cgroup.c
> index 274c73fea..43055e8cf 100644
> --- a/lib/tst_cgroup.c
> +++ b/lib/tst_cgroup.c
> @@ -1112,6 +1112,15 @@ const char *tst_cg_group_name(const struct tst_cg_group *const cg)
>  	return cg->group_name;
>  }
>  
> +int tst_cg_group_unified_dir_fd(const struct tst_cg_group *const cg)
> +{
> +	for (int i = 0; cg->dirs[i]; i++) {
> +		if (cg->dirs[i]->dir_root->ver == TST_CG_V2)
> +			return cg->dirs[i]->dir_fd;

The loop is unecessary; cg->dirs_by_ctrl[0] is always the V2 directory
if it exists.

Otherwise the test LGTM. I'll set to changes requested in patchwork.

-- 
Thank you,
Richard.

-- 
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