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authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-19 10:23:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-19 10:23:24 -0700
commit1335d9a1fb2abbe5022de3c517989cc7c7161dee (patch)
tree23e4a27cb22bb09fefea09a62e419a8c5bcc32cd /mm
parent4c4a5c99af7f479a14759196f8df9467128f3baf (diff)
parent8ea58f1e8b11cca3087b294779bf5959bf89cc10 (diff)
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Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core fixes from Ingo Molnar: "This fixes a particularly thorny munmap() bug with MPX, plus fixes a host build environment assumption in objtool" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Allow AR to be overridden with HOSTAR x86/mpx, mm/core: Fix recursive munmap() corruption
Diffstat (limited to 'mm')
-rw-r--r--mm/mmap.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index bd7b9f293b39..2d6a6662edb9 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2735,9 +2735,17 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
return -EINVAL;
len = PAGE_ALIGN(len);
+ end = start + len;
if (len == 0)
return -EINVAL;
+ /*
+ * arch_unmap() might do unmaps itself. It must be called
+ * and finish any rbtree manipulation before this code
+ * runs and also starts to manipulate the rbtree.
+ */
+ arch_unmap(mm, start, end);
+
/* Find the first overlapping VMA */
vma = find_vma(mm, start);
if (!vma)
@@ -2746,7 +2754,6 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
/* we have start < vma->vm_end */
/* if it doesn't overlap, we have nothing.. */
- end = start + len;
if (vma->vm_start >= end)
return 0;
@@ -2816,12 +2823,6 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
/* Detach vmas from rbtree */
detach_vmas_to_be_unmapped(mm, vma, prev, end);
- /*
- * mpx unmap needs to be called with mmap_sem held for write.
- * It is safe to call it before unmap_region().
- */
- arch_unmap(mm, vma, start, end);
-
if (downgrade)
downgrade_write(&mm->mmap_sem);