Re: [LTP] [PATCH v2] listmount04.c: Update case support mnt_id_req.mnt_ns_fd

[Petr Vorel <pvorel@suse.cz>]

Hi Wei,

> New kernel commit lead test case failure with following error message:
"New" will eventually become "old" :). Why not to state that it's change from
v6.18-rc7? (it saves people in the future to search.)

> listmount04.c:128: TFAIL: invalid mnt_id_req.spare expected EINVAL: EBADF (9)

2 things needs to be changed.

> Detail of new kernel commit:
> commit: 78f0e33cd6c939a555aa80dbed2fec6b333a7660
> fs/namespace: correctly handle errors returned by grab_requested_mnt_ns

> Signed-off-by: Wei Gao <wegao@suse.com>
> ---
>  configure.ac                                    |  1 +
>  .../kernel/syscalls/listmount/listmount04.c     | 17 +++++++++++++++++
>  2 files changed, 18 insertions(+)

> diff --git a/configure.ac b/configure.ac
> index 0480f46ca..fcff90799 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -263,6 +263,7 @@ AC_CHECK_TYPES([struct cachestat],,,[#include <sys/mman.h>])

>  # Defined in <linux/mount.h>, but include/lapi/mount.h includes <sys/mount.h> */
>  AC_CHECK_TYPES([struct mnt_id_req],,,[#include <sys/mount.h>])
> +AC_CHECK_MEMBERS([struct mnt_id_req.mnt_ns_fd],,,[#include <sys/mount.h>])
>  AC_CHECK_TYPES([struct statmount],,,[#include <sys/mount.h>])
>  AC_CHECK_MEMBERS([struct statmount.mnt_ns_id],,,[#include <unistd.h>
>  #include <linux/mount.h>])
> diff --git a/testcases/kernel/syscalls/listmount/listmount04.c b/testcases/kernel/syscalls/listmount/listmount04.c
> index a52bad064..0a198e6a9 100644
> --- a/testcases/kernel/syscalls/listmount/listmount04.c
> +++ b/testcases/kernel/syscalls/listmount/listmount04.c
> @@ -26,7 +26,11 @@ static uint64_t mnt_ids[MNT_SIZE];
>  static struct tcase {
>  	int req_usage;
>  	uint32_t size;
> +#ifdef HAVE_STRUCT_MNT_ID_REQ_MNT_NS_FD

Any time you modify configure.ac please remember to use:

#include "config.h"

> +	uint32_t mnt_ns_fd;
> +#else
>  	uint32_t spare;
> +#endif
>  	uint64_t mnt_id;
>  	uint64_t param;
>  	uint64_t *mnt_ids;
> @@ -73,12 +77,21 @@ static struct tcase {
>  	{
>  		.req_usage = 1,
>  		.size = MNT_ID_REQ_SIZE_VER0,
> +#ifdef HAVE_STRUCT_MNT_ID_REQ_MNT_NS_FD
> +		.mnt_ns_fd = -1,
> +#else
>  		.spare = -1,
> +#endif
>  		.mnt_id = LSMT_ROOT,
>  		.mnt_ids = mnt_ids,
>  		.nr_mnt_ids = MNT_SIZE,
> +#ifdef HAVE_STRUCT_MNT_ID_REQ_MNT_NS_FD
> +		.exp_errno = EBADF,
> +		.msg = "invalid mnt_id_req.mnt_ns_fd bad file descriptor",
> +#else
>  		.exp_errno = EINVAL,
>  		.msg = "invalid mnt_id_req.spare",
> +#endif

I tried to run it on VM with affected (new) libc and old kernel and it fails:

tst_test.c:2028: TINFO: Tested kernel: 6.12.38+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.38-1 (2025-07-16) x86_64
tst_kconfig.c:88: TINFO: Parsing kernel config '/boot/config-6.12.38+deb13-amd64'
tst_test.c:1846: TINFO: Overall timeout per run is 0h 00m 30s
listmount04.c:146: TPASS: request points to unaccessible memory : EFAULT (14)
listmount04.c:146: TPASS: mnt_ids points to unaccessible memory : EFAULT (14)
listmount04.c:146: TPASS: invalid flags : EINVAL (22)
listmount04.c:146: TPASS: insufficient mnt_id_req.size : EINVAL (22)
listmount04.c:146: TFAIL: invalid mnt_id_req.mnt_ns_fd bad file descriptor expected EBADF: EINVAL (22)

Usual "headers vs running kernel mismatch problem".
@Li, @Cyril Do we care about these incompatibilities? Could we just accept both?
Or we don't care?

Obviously it works on new enough kernel (patch change is from 6.18):

tst_test.c:2028: TINFO: Tested kernel: 6.17.11+deb14-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.17.11-1 (2025-12-07) x86_64
tst_kconfig.c:88: TINFO: Parsing kernel config '/boot/config-6.17.11+deb14-amd64'
tst_test.c:1846: TINFO: Overall timeout per run is 0h 00m 30s
listmount04.c:146: TPASS: request points to unaccessible memory : EFAULT (14)
listmount04.c:146: TPASS: mnt_ids points to unaccessible memory : EFAULT (14)
listmount04.c:146: TPASS: invalid flags : EINVAL (22)
listmount04.c:146: TPASS: insufficient mnt_id_req.size : EINVAL (22)
listmount04.c:146: TPASS: invalid mnt_id_req.mnt_ns_fd bad file descriptor : EBADF (9)
listmount04.c:146: TPASS: invalid mnt_id_req.param : EINVAL (22)
listmount04.c:146: TPASS: invalid mnt_id_req.mnt_id : EINVAL (22)
listmount04.c:146: TPASS: non-existant mnt_id : ENOENT (2)

Kind regards,
Petr

>  	},
>  	{
>  		.req_usage = 1,
> @@ -122,7 +135,11 @@ static void run(unsigned int n)
>  		req->mnt_id = tc->mnt_id;
>  		req->param = tc->param;
>  		req->size = tc->size;
> +#ifdef HAVE_STRUCT_MNT_ID_REQ_MNT_NS_FD
> +		req->mnt_ns_fd = tc->mnt_ns_fd;
> +#else
>  		req->spare = tc->spare;
> +#endif

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