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btrfs: set generation before calling btrfs_clean_tree_block in btrfs_init_new_buffer

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commit cbddcc4fa3 upstream.

syzbot is reporting uninit-value in btrfs_clean_tree_block() [1], for
commit bc877d285c ("btrfs: Deduplicate extent_buffer init code")
missed that btrfs_set_header_generation() in btrfs_init_new_buffer() must
not be moved to after clean_tree_block() because clean_tree_block() is
calling btrfs_header_generation() since commit 55c69072d6 ("Btrfs:
Fix extent_buffer usage when nodesize != leafsize").

Since memzero_extent_buffer() will reset "struct btrfs_header" part, we
can't move btrfs_set_header_generation() to before memzero_extent_buffer().
Just re-add btrfs_set_header_generation() before btrfs_clean_tree_block().

Link: https://syzkaller.appspot.com/bug?extid=fba8e2116a12609b6c59 [1]
Reported-by: syzbot <syzbot+fba8e2116a12609b6c59@syzkaller.appspotmail.com>
Fixes: bc877d285c ("btrfs: Deduplicate extent_buffer init code")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tetsuo Handa 2022-09-20 22:43:51 +09:00 committed by Greg Kroah-Hartman
parent 4b996a3014
commit 0a408c6212
1 changed files with 3 additions and 0 deletions
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3
fs/btrfs/extent-tree.c
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@ -4802,6 +4802,9 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
!test_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &root->state))
lockdep_owner = BTRFS_FS_TREE_OBJECTID;
/* btrfs_clean_tree_block() accesses generation field. */
btrfs_set_header_generation(buf, trans->transid);
/*
* This needs to stay, because we could allocate a freed block from an
* old tree into a new tree, so we need to make sure this new block is