[CRIU] Re: [PATCH] restore: Drop MAP_GROWSDOWN mmap flags from the stack creation

[Cyrill Gorcunov]

On Mon, Jul 23, 2012 at 02:13:03PM +0400, Cyrill Gorcunov wrote:
> This makes the kernel to treat stack area with stack
> guard page and prevent us from unmapping the whole
> VMA area at late sigreturn call, which forces restored
> program to carry zero sized VMA which previously belong
> to a guard page.
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
>  cr-restore.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/cr-restore.c b/cr-restore.c
> index 256ae77..c320978 100644
> --- a/cr-restore.c
> +++ b/cr-restore.c
> @@ -486,7 +486,7 @@ static inline int fork_with_pid(struct pstree_item *item, unsigned long ns_clone
>  	pr_info("Forking task with %d pid (flags 0x%lx)\n", pid, ns_clone_flags);
>  
>  	stack = mmap(NULL, STACK_SIZE, PROT_WRITE | PROT_READ,
> -			MAP_PRIVATE | MAP_GROWSDOWN | MAP_ANONYMOUS, -1, 0);
> +			MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
>  	if (stack == MAP_FAILED) {
>  		pr_perror("Failed to map stack for the child");
>  		goto err;

Drop it please, the real reason is simplier, will update.

	Cyrill