[LTP] [PATCH] syscalls/setrlimit: add setrlimit04

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> 
> Hi Jan,
> 
> Jan Stancek writes:
> 
> > + *   DESCRIPTION
> > + *     Attempt to run a trivial binary with stack < 1MB.
> > + *
> > + *     Early patches for stack guard gap caused that gap size was
> > + *     contributing towards stack limit. This caused failures
> > + *     for new processes (E2BIG) when ulimit was set to anything
> > + *     lower than size of gap. commit 1be7107fbe18 "mm: larger
> > + *     stack guard gap, between vmas" sets default gap size to 1M
> > + *     (for systems with 4k pages), so let's set stack limit to 512kB
> > + *     and confirm we can still run some trivial binary.
> > + */
> 
> The first sentance is difficult to parse. I think you are saying that in
> the early patches the stack gaurd gap was included in the stack
> size.

Yes. I didn't dig into details, but I think your formula below
is close.

> The stack size is then compared to the stack limit, so a process
> would fail to start if
> 
> [initial process stack usage] + [stack gap] > [stack limit].
> 
> However the stack gap should not be included in this calculation.