[LTP] lapi/prctl: add more fallback definitions

[linuxtestproject.agent@gmail.com]

Hi Andrea,

On Aug 26, 2026, Andrea Cervesato wrote:
> lapi/prctl: add more fallback definitions

--- [PATCH 1/2] ---

> +#ifndef PR_SET_MM_MAP
> +# define PR_SET_MM_MAP	14
> +#endif
> +#ifndef PR_SET_MM_MAP_SIZE
> +# define PR_SET_MM_MAP_SIZE	15
> +#endif
> +
> +#if !(HAVE_STRUCT_PRCTL_MM_MAP) && !defined(PR_SET_MM_MAP)
> +struct prctl_mm_map {

Could the struct guard depend only on HAVE_STRUCT_PRCTL_MM_MAP? Since
PR_SET_MM_MAP is defined immediately above, !defined(PR_SET_MM_MAP) is always
false here. On systems missing struct prctl_mm_map, the fallback is therefore
not emitted and ghostlock.c fails to compile.

--- [PATCH 2/2] ---

> +	map.start_code = map.start_data = map.end_data =
> +	map.start_brk = map.brk = map.start_stack = map.arg_start =
> +	map.arg_end = map.env_start = map.env_end = (uint64_t)(uintptr_t)&sz;
> +	map.end_code = map.start_code + 0x1000;

Could this probe use the real process map values, as waiter_fn() does? A
successful PR_SET_MM_MAP call writes these values into current->mm. In
particular, start_brk and brk remain set to setup()'s local stack address
after setup() returns. A later brk() allocation below that address is rejected
as being below mm->start_brk, so pthread creation or another allocation can
fail for a reason unrelated to the CVE.

> +static struct tst_test test = {
> +	.setup = setup,
> +	.test_all = run,
> +	.runtime = 180,

Could this declare .min_kver = "3.18", or otherwise treat EINVAL from
PR_SET_MM_MAP_SIZE as an unavailable prerequisite? PR_SET_MM_MAP was added in
Linux 3.18, while the CVE affects older kernels. On such a kernel,
SAFE_PRCTL() currently reports TBROK rather than TCONF.

>  cve-2014-0196 cve-2016-7117 cve-2017-2671 cve-2017-17052 cve-2017-17053 refluxfs:  CFLAGS += -pthread
> +cve-2014-0196 cve-2016-7117 cve-2017-2671 cve-2017-17052 cve-2017-17053 ghostlock:  CFLAGS += -pthread

Could ghostlock be added to the existing assignment instead? The new line
passes -pthread twice to every pre-existing target listed there.

>  refluxfs
>  sctphantom
> +ghostlock

Could ghostlock be inserted in sorted order?

Verdict - Needs revision

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LTP AI Reviewer