diff options
Diffstat (limited to 'tags/2.6.18-12/30039_hugetlb-prio_tree-unit-fix.patch')
| -rw-r--r-- | tags/2.6.18-12/30039_hugetlb-prio_tree-unit-fix.patch | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/tags/2.6.18-12/30039_hugetlb-prio_tree-unit-fix.patch b/tags/2.6.18-12/30039_hugetlb-prio_tree-unit-fix.patch new file mode 100644 index 0000000..2b92bf0 --- /dev/null +++ b/tags/2.6.18-12/30039_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); |