From: Chris Mason <clm@fb.com>
Date: Tue, 7 Apr 2015 01:17:00 +0000 (-0700)
Subject: Btrfs: fix use after free when close_ctree frees the orphan_rsv
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=cdfb080e1853660952db5e5332727e59427856df;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

Btrfs: fix use after free when close_ctree frees the orphan_rsv

Near the end of close_ctree, we're calling btrfs_free_block_rsv
to free up the orphan rsv.  The problem is this call updates the
space_info, which has already been freed.

This adds a new __ function that directly calls kfree instead of trying
to update the space infos.

Signed-off-by: Chris Mason <clm@fb.com>
---

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 83051fae9467..10b6a75ab7e6 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3470,6 +3470,7 @@ struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
 					      unsigned short type);
 void btrfs_free_block_rsv(struct btrfs_root *root,
 			  struct btrfs_block_rsv *rsv);
+void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv);
 int btrfs_block_rsv_add(struct btrfs_root *root,
 			struct btrfs_block_rsv *block_rsv, u64 num_bytes,
 			enum btrfs_reserve_flush_enum flush);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b5e3d5f6400a..62cd3b63190d 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3766,7 +3766,7 @@ void close_ctree(struct btrfs_root *root)
 
 	btrfs_free_stripe_hash_table(fs_info);
 
-	btrfs_free_block_rsv(root, root->orphan_block_rsv);
+	__btrfs_free_block_rsv(root->orphan_block_rsv);
 	root->orphan_block_rsv = NULL;
 
 	lock_chunks(root);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 02c2b29a0840..875ba519a131 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4918,6 +4918,11 @@ void btrfs_free_block_rsv(struct btrfs_root *root,
 	kfree(rsv);
 }
 
+void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
+{
+	kfree(rsv);
+}
+
 int btrfs_block_rsv_add(struct btrfs_root *root,
 			struct btrfs_block_rsv *block_rsv, u64 num_bytes,
 			enum btrfs_reserve_flush_enum flush)