[PATCH v3 2/6] support: Add use_stack_min option to support_small_thread_stack_size
H.J. Lu
hjl.tools@gmail.com
Tue May 19 20:52:09 GMT 2026
On Tue, May 19, 2026 at 9:26 PM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
> It allows it to return PTHREAD_STACK_MIN if defined.
>
> Checked on x86_64-linux-gnu and with a build for i686-gnu.
>
> Suggested-by: H.J. Lu <hjl.tools@gmail.com>
> ---
> elf/tst-bz26577-minstack.c | 7 +------
> elf/tst-decorate-maps.c | 2 +-
> nptl/tst-guard1.c | 4 ++--
> stdlib/tst-canon-bz26341.c | 2 +-
> support/support_set_small_thread_stack_size.c | 13 +++++++++----
> support/support_small_stack_thread_attribute.c | 2 +-
> support/xthread.h | 12 +++++++-----
> sysdeps/unix/sysv/linux/tst-sem_getvalue-affinity.c | 2 +-
> .../unix/sysv/linux/tst-skeleton-thread-affinity.c | 2 +-
> 9 files changed, 24 insertions(+), 22 deletions(-)
>
> diff --git a/elf/tst-bz26577-minstack.c b/elf/tst-bz26577-minstack.c
> index 741b307392a..9d5ecd85939 100644
> --- a/elf/tst-bz26577-minstack.c
> +++ b/elf/tst-bz26577-minstack.c
> @@ -51,12 +51,7 @@ static int
> do_test (void)
> {
> char *path = xasprintf ("%s/elf/tst-bz26577-mod.so", support_objdir_root);
> - size_t stacksize =
> -#ifdef PTHREAD_STACK_MIN
> - PTHREAD_STACK_MIN;
> -#else
> - support_small_thread_stack_size ();
> -#endif
> + size_t stacksize = support_small_thread_stack_size (true);
>
> pthread_attr_t attr;
> xpthread_attr_init (&attr);
> diff --git a/elf/tst-decorate-maps.c b/elf/tst-decorate-maps.c
> index fa3637af899..b6af31c7274 100644
> --- a/elf/tst-decorate-maps.c
> +++ b/elf/tst-decorate-maps.c
> @@ -128,7 +128,7 @@ do_test_threads (bool set_guard)
> {
> pthread_attr_t attr;
> xpthread_attr_init (&attr);
> - size_t stacksize = support_small_thread_stack_size ();
> + size_t stacksize = support_small_thread_stack_size (false);
> void *stack = xmmap (0,
> stacksize,
> PROT_READ | PROT_WRITE,
> diff --git a/nptl/tst-guard1.c b/nptl/tst-guard1.c
> index b97ad23de41..3486cba9e4d 100644
> --- a/nptl/tst-guard1.c
> +++ b/nptl/tst-guard1.c
> @@ -176,7 +176,7 @@ do_test1 (void *closure)
> pthread_attr_t attr;
> xpthread_attr_init (&attr);
>
> - size_t stacksize = support_small_thread_stack_size ();
> + size_t stacksize = support_small_thread_stack_size (false);
> void *stack = xmmap (0,
> stacksize,
> PROT_READ | PROT_WRITE,
> @@ -201,7 +201,7 @@ do_test2 (void *closure)
> pthread_attr_t attr;
> xpthread_attr_init (&attr);
>
> - size_t stacksize = support_small_thread_stack_size ();
> + size_t stacksize = support_small_thread_stack_size (false);
> void *stack = xmmap (0,
> stacksize,
> PROT_READ | PROT_WRITE,
> diff --git a/stdlib/tst-canon-bz26341.c b/stdlib/tst-canon-bz26341.c
> index 4860818a4e7..e94c924ac1c 100644
> --- a/stdlib/tst-canon-bz26341.c
> +++ b/stdlib/tst-canon-bz26341.c
> @@ -81,7 +81,7 @@ do_realpath (void *arg)
> const size_t syscall_usage = 1 * PATH_MAX + 1024;
> const size_t realpath_usage = 2 * PATH_MAX + 1024;
> const size_t thread_usage = 1 * PATH_MAX + 1024;
> - size_t stack_size = support_small_thread_stack_size ()
> + size_t stack_size = support_small_thread_stack_size (false)
> - syscall_usage - realpath_usage - thread_usage;
> char stack[stack_size];
> char *resolved = stack + stack_size - thread_usage + 1024;
> diff --git a/support/support_set_small_thread_stack_size.c b/support/support_set_small_thread_stack_size.c
> index 6c2cd4f92ba..51ec05b3229 100644
> --- a/support/support_set_small_thread_stack_size.c
> +++ b/support/support_set_small_thread_stack_size.c
> @@ -21,13 +21,16 @@
> #include <support/xthread.h>
>
> size_t
> -support_small_thread_stack_size (void)
> +support_small_thread_stack_size (bool use_stack_min)
> {
> /* Some architectures have too small values for PTHREAD_STACK_MIN
> which cannot be used for creating threads. Ensure that the stack
> - size is at least 256 KiB. */
> + size is at least 256 KiB if USE_STACK_MIN is false. */
> size_t stack_size = 256 * 1024;
> #ifdef PTHREAD_STACK_MIN
> + if (use_stack_min)
> + return PTHREAD_STACK_MIN;
> +
> if (stack_size < PTHREAD_STACK_MIN)
> stack_size = PTHREAD_STACK_MIN;
> #endif
> @@ -35,7 +38,9 @@ support_small_thread_stack_size (void)
> }
>
> void
> -support_set_small_thread_stack_size (pthread_attr_t *attr)
> +support_set_small_thread_stack_size (pthread_attr_t *attr,
> + bool use_stack_min)
> {
> - xpthread_attr_setstacksize (attr, support_small_thread_stack_size ());
> + xpthread_attr_setstacksize
> + (attr, support_small_thread_stack_size (use_stack_min));
> }
> diff --git a/support/support_small_stack_thread_attribute.c b/support/support_small_stack_thread_attribute.c
> index dd97e421464..229deabe9e4 100644
> --- a/support/support_small_stack_thread_attribute.c
> +++ b/support/support_small_stack_thread_attribute.c
> @@ -24,7 +24,7 @@ allocate (void *closure)
> {
> pthread_attr_t *result = malloc (sizeof (*result));
> xpthread_attr_init (result);
> - support_set_small_thread_stack_size (result);
> + support_set_small_thread_stack_size (result, false);
> return result;
> }
>
> diff --git a/support/xthread.h b/support/xthread.h
> index d585bd0c3c6..3bdc6907aab 100644
> --- a/support/xthread.h
> +++ b/support/xthread.h
> @@ -90,11 +90,13 @@ void xpthread_attr_setguardsize (pthread_attr_t *attr,
>
> void xpthread_kill (pthread_t thr, int signo);
>
> -/* Return the stack size used on support_set_small_thread_stack_size. */
> -size_t support_small_thread_stack_size (void);
> -/* Set the stack size in ATTR to a small value, but still large enough
> - to cover most internal glibc stack usage. */
> -void support_set_small_thread_stack_size (pthread_attr_t *attr);
> +/* Return the stack size used on support_set_small_thread_stack_size,
> + or PTHREAD_STACK_MIN (if defined) is USE_STACK_MIN is set. */
> +size_t support_small_thread_stack_size (bool use_stack_min);
> +/* Set the stack size in ATTR to a small value. Use PTHREAD_STACK_MIN (if
> + defined) or a large enough to cover most internal glibc stack usage. */
> +void support_set_small_thread_stack_size (pthread_attr_t *attr,
> + bool use_stack_min);
>
> /* Return a pointer to a thread attribute which requests a small
> stack. The caller must not free this pointer. */
> diff --git a/sysdeps/unix/sysv/linux/tst-sem_getvalue-affinity.c b/sysdeps/unix/sysv/linux/tst-sem_getvalue-affinity.c
> index c4c430edebd..f30e0bbed51 100644
> --- a/sysdeps/unix/sysv/linux/tst-sem_getvalue-affinity.c
> +++ b/sysdeps/unix/sysv/linux/tst-sem_getvalue-affinity.c
> @@ -136,7 +136,7 @@ early_test (struct conf *conf)
> printf ("error: pthread_attr_init failed: %s\n", strerror (ret));
> return false;
> }
> - support_set_small_thread_stack_size (&attr);
> + support_set_small_thread_stack_size (&attr, false);
>
> /* Spawn a thread pinned to each available CPU. */
> for (int cpu = 0; cpu <= conf->last_cpu; ++cpu)
> diff --git a/sysdeps/unix/sysv/linux/tst-skeleton-thread-affinity.c b/sysdeps/unix/sysv/linux/tst-skeleton-thread-affinity.c
> index 323b2e0ffc4..4477fde150d 100644
> --- a/sysdeps/unix/sysv/linux/tst-skeleton-thread-affinity.c
> +++ b/sysdeps/unix/sysv/linux/tst-skeleton-thread-affinity.c
> @@ -208,7 +208,7 @@ early_test (struct conf *conf)
> printf ("error: pthread_attr_init failed: %s\n", strerror (ret));
> return false;
> }
> - support_set_small_thread_stack_size (&attr);
> + support_set_small_thread_stack_size (&attr, false);
>
> /* This count assumes that all the threads below are created
> successfully, and call pthread_barrier_wait(). If any threads
> --
> 2.43.0
>
LGTM.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Thanks.
--
H.J.
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