maple_tree: fix a potential memory leak, OOB access, or other unpredictable bug

In mas_alloc_nodes(), "node->node_count = 0" means to initialize the
node_count field of the new node, but the node may not be a new node.  It
may be a node that existed before and node_count has a value, setting it
to 0 will cause a memory leak.  At this time, mas->alloc->total will be
greater than the actual number of nodes in the linked list, which may
cause many other errors.  For example, out-of-bounds access in
mas_pop_node(), and mas_pop_node() may return addresses that should not be
used.  Fix it by initializing node_count only for new nodes.

Also, by the way, an if-else statement was removed to simplify the code.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions