Hello,
execve() system call should support argument length of
MAX_ARG_STRLEN (PAGE_SIZE * 32). On 64K page size systems, we
are not able to pass 32 * PAGE_SIZE arguments into the execve()
system call because of the following reasons.
* struct linux_binprm's vma starts with a size of PAGE_SIZE
vma->vm_end = STACK_TOP_MAX;
vma->vm_start = vma->vm_end - PAGE_SIZE;
* The VMA expands as much depending upon the argument size. So
for 32 * PAGE_SIZE argument, it becomes 33 * PAGE_SIZE.
* 33 * PAGE_SIZE with 64K pages fails the following test in
get_arg_page() function. 33 * PAGE_SIZE is more than 2MB
(8 MB /4) with 64K page size.
if (size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4)
* Right now RLIMIT_STACK is hard coded 8MB which does not take
PAGE_SIZE into account.
Wondering what should be the solution for this problem ?
* Change the default stack size from 8MB ?
* Change the ratio test from 1/4th ?
Thoughts ?
Regards
Anshuman
