[LTP] [PATCH 2/2] mmap18: Increase minimal stack mapping to 8KB

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> The first testcase keeps segfaulting on older kernels with only 4KB initial
> stack mapping
> 
> Signed-off-by: Martin Doucha <mdoucha@suse.cz>
> ---
> 
> Note: Increasing initial stack size to 8KB fixes the segfaults but I'm not
> entirely sure whether we shouldn't use PTHREAD_STACK_MIN as the minimal size
> instead. Pthread man page isn't entirely clear whether PTHREAD_STACK_MIN is
> the minimal value for stack size after it grows to the limit, or the minimal
> size of the initial stack mapping (before it starts growing).

I vote for passing down PTHREAD_STACK_MIN for the initial mapping.

> On x86_64, PTHREAD_STACK_MIN is 4 pages (16KB). On PPC64, it's 2 pages
> (128KB).
> 
>  testcases/kernel/syscalls/mmap/mmap18.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/testcases/kernel/syscalls/mmap/mmap18.c b/testcases/kernel/syscalls/mmap/mmap18.c
> index 966bf673e..8b149fb93 100644
> --- a/testcases/kernel/syscalls/mmap/mmap18.c
> +++ b/testcases/kernel/syscalls/mmap/mmap18.c
> @@ -201,10 +201,11 @@ static void grow_stack_fail(size_t stack_size, size_t mapped_size)
>  static void run_test(void)
>  {
>  	size_t stack_size = 8 * PTHREAD_STACK_MIN;
> +	size_t minsize = MAX(page_size, 8192);
>  
> -	grow_stack_success(stack_size, page_size);
> +	grow_stack_success(stack_size, minsize);
>  	grow_stack_success(stack_size, stack_size/2);
> -	grow_stack_fail(stack_size, page_size);
> +	grow_stack_fail(stack_size, minsize);
>  	grow_stack_fail(stack_size, stack_size/2);
>  }
>  
> -- 
> 2.28.0
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz