[PATCH] disk-io.c (open_ctree): Don't dereference NULL upon failed kzalloc

[Jim Meyering]

I was looking at how *alloc-returned values are dereferenced,
and spotted two potential NULL dereferences (then stopped looking, for now):

changeset:   708:eecfd989f8c6
tag:         tip
user:        Jim Meyering <[EMAIL PROTECTED]>
date:        Tue Sep 09 16:02:31 2008 +0200
files:       disk-io.c
description:
disk-io.c (open_ctree): don't dereference NULL upon failed kzalloc


diff --git a/disk-io.c b/disk-io.c
--- a/disk-io.c
+++ b/disk-io.c
@@ -1321,35 +1321,36 @@ struct btrfs_root *open_ctree(struct sup
        struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
                                                 GFP_NOFS);
        struct btrfs_root *tree_root = kzalloc(sizeof(struct btrfs_root),
                                               GFP_NOFS);
        struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
                                                GFP_NOFS);
        struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
                                                GFP_NOFS);
        struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
                                              GFP_NOFS);
        struct btrfs_root *log_tree_root;
 
        int ret;
        int err = -EINVAL;
 
        struct btrfs_super_block *disk_super;
 
-       if (!extent_root || !tree_root || !fs_info) {
+       if (!extent_root || !tree_root || !fs_info
+           || !chunk_root || !dev_root) {
                err = -ENOMEM;
                goto fail;
        }
        INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
        INIT_LIST_HEAD(&fs_info->trans_list);
        INIT_LIST_HEAD(&fs_info->dead_roots);
        INIT_LIST_HEAD(&fs_info->hashers);
        INIT_LIST_HEAD(&fs_info->delalloc_inodes);
        spin_lock_init(&fs_info->hash_lock);
        spin_lock_init(&fs_info->delalloc_lock);
        spin_lock_init(&fs_info->new_trans_lock);
        spin_lock_init(&fs_info->ref_cache_lock);
 
        init_completion(&fs_info->kobj_unregister);
        fs_info->tree_root = tree_root;
        fs_info->extent_root = extent_root;
        fs_info->chunk_root = chunk_root;


Here are some offending dereferences:

        chunk_root->node = read_tree_block(chunk_root,
...
        dev_root->track_dirty = 1;
--
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