Re: [LTP] lapi/sched: add SAFE_SCHED_SETATTR()

[linuxtestproject.agent@gmail.com]

Hi Andrea,

On Sep 2, 2026, Andrea Cervesato wrote:
> lapi/sched: add SAFE_SCHED_SETATTR()

--- [PATCH 1/3] ---

> static inline int safe_sched_setattr(const char *file, const int lineno,
> 				     pid_t pid, const struct sched_attr *attr,
> 				     unsigned int flags)
> {
> 	int ret;
>
> 	ret = sched_setattr(pid, attr, flags);

glibc's sched_setattr() takes a non-const struct sched_attr pointer, so this
discards const and fails with -Werror=discarded-qualifiers on the new glibc
API. Match that prototype here and in the fallback declaration.

> #define SAFE_SCHED_SETATTR(pid, attr, flags)\
> 	safe_sched_setattr(__FILE__, __LINE__, (pid), (attr), (flags))

This new public macro needs a kernel-doc comment documenting its arguments
and failure behavior.

--- [PATCH 2/3] ---

> #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 {

The fallback struct is unreachable when needed because PR_SET_MM_MAP is
defined immediately before the condition. Gate it solely on
HAVE_STRUCT_PRCTL_MM_MAP, otherwise the new CVE test fails to compile on
systems lacking the struct.

--- [PATCH 3/3] ---

> static struct tst_test test = {
> 	.setup = setup,
> 	.test_all = run,
> 	.runtime = 180,
> 	.needs_checkpoints = 1,

PR_SET_MM_MAP was added in Linux 3.18. Add .min_kver = "3.18"; otherwise
3.3--3.17 kernels with both requested configs reach setup and report TBROK
for the unsupported operation.

> 	SAFE_CLOCK_GETTIME(CLOCK_MONOTONIC, &ts);
> 	ts = tst_timespec_add(ts, (struct timespec){ .tv_sec = 10, .tv_nsec = 0 });
> 	futex_wait_requeue_pi(&f_wait, &f_pi_target, &ts);
>
> 	TST_CHECKPOINT_WAKE(CP_SPRAYED);

The futex result is ignored, so expiry or another failure publishes
CP_SPRAYED without establishing the PI topology and causes a spurious TBROK.
Use an untimed blocking wait, or validate the result before the wake.

> refluxfs
> sctphantom
> ghostlock

Keep the new .gitignore entry sorted by placing ghostlock before refluxfs.

Verdict - Needs revision

---
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