diff options
author | Qu Wenruo <wqu@suse.com> | 2017-11-22 17:03:16 +0800 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2018-01-03 17:09:09 +0100 |
commit | 702298b2d9eed782c30d85a207006731ebdfc78a (patch) | |
tree | cf19f71e02ced0e9e28e0785b8241d5907958b5e | |
parent | beb06b63cc9a54f0d33dae43c3c6ff956ccc885a (diff) |
btrfs-progs: lowmem check: Fix NULL pointer access caused by large tree reloc tree
[BUG]
v4.14 btrfs-progs can't pass new self test image with large tree reloc
trees. It will fail with later "shared_block_ref_only.raw.xz" test
image with NULL pointer access.
[CAUSE]
For image with higher (level >= 2) tree reloc tree, for function
need_check() its ulist will be empty as tree reloc tree won't be
accounted in btrfs_find_all_roots(). Then accessing ulist->roots with
rb_first() will return NULL pointer.
[FIX]
For need_check() function, if @roots is empty, meaning it's a tree reloc
tree, always check them. Although this can be slow, but at least it's
safe that we won't skip any possible wrong tree block.
Fixes: 5e2dc770471b ("btrfs-progs: check: skip shared node or leaf check for low_memory mode")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r-- | cmds-check.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/cmds-check.c b/cmds-check.c index 644ee084..03ff89a4 100644 --- a/cmds-check.c +++ b/cmds-check.c @@ -2149,7 +2149,12 @@ static int need_check(struct btrfs_root *root, struct ulist *roots) struct rb_node *node; struct ulist_node *u; - if (roots->nnodes == 1) + /* + * @roots can be empty if it belongs to tree reloc tree + * In that case, we should always check the leaf, as we can't use + * the tree owner to ensure some other root will check it. + */ + if (roots->nnodes == 1 || roots->nnodes == 0) return 1; node = rb_first(&roots->root); |