From 8a14f4d8328cc8615f8a5487c4173f36a8314796 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 20 May 2016 17:02:44 -0700 Subject: [PATCH] radix-tree: fix radix_tree_create for sibling entries If the radix tree user attempted to insert a colliding entry with an existing multiorder entry, then radix_tree_create() could encounter a sibling entry when walking down the tree to look for a slot. Use radix_tree_descend() to fix the problem, and add a test-case to make sure the problem doesn't come back in future. Signed-off-by: Matthew Wilcox Reviewed-by: Ross Zwisler Cc: Konstantin Khlebnikov Cc: Kirill Shutemov Cc: Jan Kara Cc: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/radix-tree.c | 4 ++-- tools/testing/radix-tree/multiorder.c | 5 +++++ 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/lib/radix-tree.c b/lib/radix-tree.c index b1ca74489bc2..9b5d8a963897 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -548,9 +548,9 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, /* Go a level down */ height--; shift -= RADIX_TREE_MAP_SHIFT; - offset = (index >> shift) & RADIX_TREE_MAP_MASK; node = indirect_to_ptr(slot); - slot = node->slots[offset]; + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + offset = radix_tree_descend(node, &slot, offset); } #ifdef CONFIG_RADIX_TREE_MULTIORDER diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c index 1b6fc9b19930..fc934578e1ef 100644 --- a/tools/testing/radix-tree/multiorder.c +++ b/tools/testing/radix-tree/multiorder.c @@ -135,6 +135,11 @@ static void multiorder_check(unsigned long index, int order) item_check_absent(&tree, i); for (i = max; i < 2*max; i++) item_check_absent(&tree, i); + for (i = min; i < max; i++) { + static void *entry = (void *) + (0xA0 | RADIX_TREE_EXCEPTIONAL_ENTRY); + assert(radix_tree_insert(&tree, i, entry) == -EEXIST); + } assert(item_delete(&tree, index) != 0); -- 2.20.1