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 <>
Acked-by: default avatarHugh Dickins <>
Signed-off-by: default avatarLinus Torvalds <>
parent f4cb767d
......@@ -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))
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