46 lines
1.4 KiB
Diff
46 lines
1.4 KiB
Diff
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From bd726c90b6b8ce87602208701b208a208e6d5600 Mon Sep 17 00:00:00 2001
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From: Helge Deller <deller@gmx.de>
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Date: Mon, 19 Jun 2017 17:34:05 +0200
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Subject: [PATCH] Allow stack to grow up to address space limit
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Fix expand_upwards() on architectures with an upward-growing stack (parisc,
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metag and partly IA-64) to allow the stack to reliably grow exactly up to
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the address space limit given by TASK_SIZE.
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Signed-off-by: Helge Deller <deller@gmx.de>
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Acked-by: Hugh Dickins <hughd@google.com>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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mm/mmap.c | 13 ++++++++-----
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1 file changed, 8 insertions(+), 5 deletions(-)
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diff --git a/mm/mmap.c b/mm/mmap.c
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index 290b77d9a01e0..a5e3dcd75e79f 100644
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--- a/mm/mmap.c
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+++ b/mm/mmap.c
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@@ -2230,16 +2230,19 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
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if (!(vma->vm_flags & VM_GROWSUP))
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return -EFAULT;
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- /* Guard against wrapping around to address 0. */
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+ /* Guard against exceeding limits of the address space. */
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address &= PAGE_MASK;
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- address += PAGE_SIZE;
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- if (!address)
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+ if (address >= TASK_SIZE)
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return -ENOMEM;
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+ address += PAGE_SIZE;
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/* Enforce stack_guard_gap */
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gap_addr = address + stack_guard_gap;
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- if (gap_addr < address)
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- return -ENOMEM;
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+
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+ /* Guard against overflow */
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+ if (gap_addr < address || gap_addr > TASK_SIZE)
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+ gap_addr = TASK_SIZE;
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+
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next = vma->vm_next;
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if (next && next->vm_start < gap_addr) {
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if (!(next->vm_flags & VM_GROWSUP))
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