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btrfs: relocation: Only remove reloc rb_trees if reloc control has been initialized

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Invalid reloc tree can cause kernel NULL pointer dereference when btrfs
does some cleanup of the reloc roots.

It turns out that fs_info::reloc_ctl can be NULL in
btrfs_recover_relocation() as we allocate relocation control after all
reloc roots have been verified.
So when we hit: note, we haven't called set_reloc_control() thus
fs_info::reloc_ctl is still NULL.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=199833
Reported-by: Xu Wen <wen.xu@gatech.edu>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Tested-by: Gu Jinxiang <gujx@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2018-07-03 17:10:07 +08:00 committed by David Sterba
parent ba480dd4db
commit 389305b2aa
1 changed files with 12 additions and 11 deletions
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23
fs/btrfs/relocation.c
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@ -1281,18 +1281,19 @@ static void __del_reloc_root(struct btrfs_root *root)
struct mapping_node *node = NULL;
struct reloc_control *rc = fs_info->reloc_ctl;
spin_lock(&rc->reloc_root_tree.lock);
rb_node = tree_search(&rc->reloc_root_tree.rb_root,
root->node->start);
if (rb_node) {
node = rb_entry(rb_node, struct mapping_node, rb_node);
rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
if (rc) {
spin_lock(&rc->reloc_root_tree.lock);
rb_node = tree_search(&rc->reloc_root_tree.rb_root,
root->node->start);
if (rb_node) {
node = rb_entry(rb_node, struct mapping_node, rb_node);
rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
}
spin_unlock(&rc->reloc_root_tree.lock);
if (!node)
return;
BUG_ON((struct btrfs_root *)node->data != root);
}
spin_unlock(&rc->reloc_root_tree.lock);
if (!node)
return;
BUG_ON((struct btrfs_root *)node->data != root);
spin_lock(&fs_info->trans_lock);
list_del_init(&root->root_list);