linux-kernel - Re: [PATCH] btrfs: check alloc return value before use handle and struct

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Message-ID: <87r5l7wtkb.fsf@basil.nowhere.org>
Date:	Wed, 19 May 2010 22:00:20 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Steven Liu <lingjiujianke@...il.com>
Cc:	chris.mason@...cle.com, linux-btrfs@...r.kernel.org,
	linux-kernel@...r.kernel.org, liuqi@...nderst.com
Subject: Re: [PATCH] btrfs: check alloc return value before use handle and struct

Steven Liu <lingjiujianke@...il.com> writes:
> diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
> index e9103b3..230a131 100644
> --- a/fs/btrfs/dir-item.c
> +++ b/fs/btrfs/dir-item.c
> @@ -142,6 +142,8 @@ int btrfs_insert_dir_item(struct
> btrfs_trans_handle *trans, struct btrfs_root
>  	key.offset = btrfs_name_hash(name, name_len);
>
>  	path = btrfs_alloc_path();
> +	if (!path)
> +		return -ENOMEM;


The big problem is handling state unwind in all the callers, not adding
it to the low level code. I attempted it some time ago but it's hard.

Just spewing BUG_ON() all over on memory allocation failure is not
helpful imho, that's not better than simply having clean NULL pointer
faults.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
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