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Commit bd726c90 authored by Helge Deller's avatar Helge Deller Committed by Linus Torvalds
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Allow stack to grow up to address space limit 



Fix expand_upwards() on architectures with an upward-growing stack (parisc,
metag and partly IA-64) to allow the stack to reliably grow exactly up to
the address space limit given by TASK_SIZE.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Acked-by: default avatarHugh Dickins <hughd@google.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f4cb767d

mm/mmap.c

+8 −5
Original line number Diff line number Diff line
@@ -2230,16 +2230,19 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) 
	if (!(vma->vm_flags & VM_GROWSUP))

		return -EFAULT;



	/* Guard against wrapping around to address 0. */

	/* Guard against exceeding limits of the address space. */

	address &= PAGE_MASK;

	address += PAGE_SIZE;

	if (!address)

	if (address >= TASK_SIZE)

		return -ENOMEM;

	address += PAGE_SIZE;



	/* Enforce stack_guard_gap */

	gap_addr = address + stack_guard_gap;

	if (gap_addr < address)

		return -ENOMEM;



	/* Guard against overflow */

	if (gap_addr < address || gap_addr > TASK_SIZE)

		gap_addr = TASK_SIZE;



	next = vma->vm_next;

	if (next && next->vm_start < gap_addr) {

		if (!(next->vm_flags & VM_GROWSUP))