Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Tue, 27 Jun 2017 12:10:34 +0100 | Subject | [PATCH 3.16 3/7] Allow stack to grow up to address space limit |
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3.16.45-rc1 review patch. If anyone has any objections, please let me know.
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From: Helge Deller <deller@gmx.de>
commit bd726c90b6b8ce87602208701b208a208e6d5600 upstream.
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: Helge Deller <deller@gmx.de> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- mm/mmap.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
--- a/mm/mmap.c +++ b/mm/mmap.c @@ -2139,16 +2139,19 @@ int expand_upwards(struct vm_area_struct 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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