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authorMatthew Wilcox <willy@linux.intel.com>2016-05-20 17:02:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-20 17:58:30 -0700
commit7b60e9ad59a31dd98c2f7ef841e2882c2b0e0f3b (patch)
treecca917997c4005d2607172a9389b63172feab0ca /lib
parent858299544efcf2577511bb018b9e73637ac71a2f (diff)
radix-tree: fix multiorder BUG_ON in radix_tree_insert
These BUG_ON tests are to ensure that all the tags are clear when inserting a new entry. If we insert a multiorder entry, we'll end up looking at the tags for a different node, and so the BUG_ON can end up triggering spuriously. Also, we now have three tags, not two, so check all three are clear, and check all the root tags with a single call to BUG_ON since the bits are stored contiguously. Include a test-case to ensure this problem does not reoccur. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/radix-tree.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index f14ada9830ca..ff460423ff4b 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -165,6 +165,11 @@ static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag)
return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT));
}
+static inline unsigned root_tags_get(struct radix_tree_root *root)
+{
+ return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT;
+}
+
/*
* Returns 1 if any slot in the node has this tag set.
* Otherwise returns 0.
@@ -604,12 +609,13 @@ int __radix_tree_insert(struct radix_tree_root *root, unsigned long index,
rcu_assign_pointer(*slot, item);
if (node) {
+ unsigned offset = get_slot_offset(node, slot);
node->count++;
- BUG_ON(tag_get(node, 0, index & RADIX_TREE_MAP_MASK));
- BUG_ON(tag_get(node, 1, index & RADIX_TREE_MAP_MASK));
+ BUG_ON(tag_get(node, 0, offset));
+ BUG_ON(tag_get(node, 1, offset));
+ BUG_ON(tag_get(node, 2, offset));
} else {
- BUG_ON(root_tag_get(root, 0));
- BUG_ON(root_tag_get(root, 1));
+ BUG_ON(root_tags_get(root));
}
return 0;