4.9-stable review patch. If anyone has any objections, please let me know.
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From: Liu Bo bo.liu@linux.alibaba.com
[ Upstream commit 80c0b4210a963e31529e15bf90519708ec947596 ]
0, 1 and <0 can be returned by btrfs_next_leaf(), and when <0 is returned, path->nodes[0] could be NULL, log_dir_items lacks such a check for <0 and we may run into a null pointer dereference panic.
Fixes: e02119d5a7b4 ("Btrfs: Add a write ahead tree log to optimize synchronous operations") Reviewed-by: Nikolay Borisov nborisov@suse.com Signed-off-by: Liu Bo bo.liu@linux.alibaba.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/tree-log.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -3399,8 +3399,11 @@ static noinline int log_dir_items(struct * from this directory and from this transaction */ ret = btrfs_next_leaf(root, path); - if (ret == 1) { - last_offset = (u64)-1; + if (ret) { + if (ret == 1) + last_offset = (u64)-1; + else + err = ret; goto done; } btrfs_item_key_to_cpu(path->nodes[0], &tmp, path->slots[0]);