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Diffstat (limited to 'tags/2.6.18-11/30039_hugetlb-prio_tree-unit-fix.patch')
-rw-r--r--tags/2.6.18-11/30039_hugetlb-prio_tree-unit-fix.patch85
1 files changed, 85 insertions, 0 deletions
diff --git a/tags/2.6.18-11/30039_hugetlb-prio_tree-unit-fix.patch b/tags/2.6.18-11/30039_hugetlb-prio_tree-unit-fix.patch
new file mode 100644
index 0000000..2b92bf0
--- /dev/null
+++ b/tags/2.6.18-11/30039_hugetlb-prio_tree-unit-fix.patch
@@ -0,0 +1,85 @@
+From: Hugh Dickins <hugh@veritas.com>
+Date: Sat, 28 Oct 2006 17:38:43 +0000 (-0700)
+Subject: [PATCH] hugetlb: fix prio_tree unit
+X-Git-Tag: v2.6.19-rc4~50
+X-Git-Url: http://git.kernel.org/gitweb.cgi?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=856fc29505556cf263f3dcda2533cf3766c14ab6
+
+[PATCH] hugetlb: fix prio_tree unit
+
+hugetlb_vmtruncate_list was misconverted to prio_tree: its prio_tree is in
+units of PAGE_SIZE (PAGE_CACHE_SIZE) like any other, not HPAGE_SIZE (whereas
+its radix_tree is kept in units of HPAGE_SIZE, otherwise slots would be
+absurdly sparse).
+
+At first I thought the error benign, just calling __unmap_hugepage_range on
+more vmas than necessary; but on 32-bit machines, when the prio_tree is
+searched correctly, it happens to ensure the v_offset calculation won't
+overflow. As it stood, when truncating at or beyond 4GB, it was liable to
+discard pages COWed from lower offsets; or even to clear pmd entries of
+preceding vmas, triggering exit_mmap's BUG_ON(nr_ptes).
+
+Signed-off-by: Hugh Dickins <hugh@veritas.com>
+Cc: Adam Litke <agl@us.ibm.com>
+Cc: David Gibson <david@gibson.dropbear.id.au>
+Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
+Signed-off-by: Andrew Morton <akpm@osdl.org>
+Signed-off-by: Linus Torvalds <torvalds@osdl.org>
+---
+
+diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
+index 0b23b96..0bea6a6 100644
+--- a/fs/hugetlbfs/inode.c
++++ b/fs/hugetlbfs/inode.c
+@@ -271,26 +271,24 @@ static void hugetlbfs_drop_inode(struct inode *inode)
+ hugetlbfs_forget_inode(inode);
+ }
+
+-/*
+- * h_pgoff is in HPAGE_SIZE units.
+- * vma->vm_pgoff is in PAGE_SIZE units.
+- */
+ static inline void
+-hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
++hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
+ {
+ struct vm_area_struct *vma;
+ struct prio_tree_iter iter;
+
+- vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) {
+- unsigned long h_vm_pgoff;
++ vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
+ unsigned long v_offset;
+
+- h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
+- v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT;
+ /*
+- * Is this VMA fully outside the truncation point?
++ * Can the expression below overflow on 32-bit arches?
++ * No, because the prio_tree returns us only those vmas
++ * which overlap the truncated area starting at pgoff,
++ * and no vma on a 32-bit arch can span beyond the 4GB.
+ */
+- if (h_vm_pgoff >= h_pgoff)
++ if (vma->vm_pgoff < pgoff)
++ v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
++ else
+ v_offset = 0;
+
+ __unmap_hugepage_range(vma,
+@@ -303,14 +301,14 @@ hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
+ */
+ static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
+ {
+- unsigned long pgoff;
++ pgoff_t pgoff;
+ struct address_space *mapping = inode->i_mapping;
+
+ if (offset > inode->i_size)
+ return -EINVAL;
+
+ BUG_ON(offset & ~HPAGE_MASK);
+- pgoff = offset >> HPAGE_SHIFT;
++ pgoff = offset >> PAGE_SHIFT;
+
+ inode->i_size = offset;
+ spin_lock(&mapping->i_mmap_lock);