linux-kernel - Re: [PATCH linux-next] fs/ntfs3: Initialize allocated memory before use

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Message-ID: <6b8a9def-30ce-4f82-9b7e-c4292f0fc5ba@paragon-software.com>
Date: Thu, 20 Nov 2025 10:07:28 +0100
From: Konstantin Komarov <almaz.alexandrovich@...agon-software.com>
To: Bartlomiej Kubik <kubik.bartlomiej@...il.com>
CC: <ntfs3@...ts.linux.dev>, <linux-kernel@...r.kernel.org>,
	<david.hunter.linux@...il.com>, <skhan@...uxfoundation.org>,
	<khalid@...nel.org>, <linux-kernel-mentees@...ts.linux.dev>,
	<syzbot+332bd4e9d148f11a87dc@...kaller.appspotmail.com>,
	<syzbot+0399100e525dd9696764@...kaller.appspotmail.com>
Subject: Re: [PATCH linux-next] fs/ntfs3: Initialize allocated memory before
 use

On 11/5/25 22:18, Bartlomiej Kubik wrote:

> KMSAN reports: Multiple uninitialized values detected:
>
> - KMSAN: uninit-value in ntfs_read_hdr (3)
> - KMSAN: uninit-value in bcmp (3)
>
> Memory is allocated by __getname(), which is a wrapper for
> kmem_cache_alloc(). This memory is used before being properly
> cleared. Change kmem_cache_alloc() to kmem_cache_zalloc() to
> properly allocate and clear memory before use.
>
> Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
> Fixes: 78ab59fee07f ("fs/ntfs3: Rework file operations")
> Tested-by: syzbot+332bd4e9d148f11a87dc@...kaller.appspotmail.com
> Reported-by: syzbot+332bd4e9d148f11a87dc@...kaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=332bd4e9d148f11a87dc
>
> Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
> Fixes: 78ab59fee07f ("fs/ntfs3: Rework file operations")
> Tested-by: syzbot+0399100e525dd9696764@...kaller.appspotmail.com
> Reported-by: syzbot+0399100e525dd9696764@...kaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=0399100e525dd9696764
>
> Signed-off-by: Bartlomiej Kubik <kubik.bartlomiej@...il.com>
> ---
>   fs/ntfs3/inode.c | 7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
> index ab61388f819c..13720baf079d 100644
> --- a/fs/ntfs3/inode.c
> +++ b/fs/ntfs3/inode.c
> @@ -1281,7 +1281,7 @@ int ntfs_create_inode(struct mnt_idmap *idmap, struct inode *dir,
>   		fa |= FILE_ATTRIBUTE_READONLY;
>
>   	/* Allocate PATH_MAX bytes. */
> -	new_de = __getname();
> +	new_de = kmem_cache_zalloc(names_cachep, GFP_KERNEL);
>   	if (!new_de) {
>   		err = -ENOMEM;
>   		goto out1;
> @@ -1723,10 +1723,9 @@ int ntfs_link_inode(struct inode *inode, struct dentry *dentry)
>   	struct NTFS_DE *de;
>
>   	/* Allocate PATH_MAX bytes. */
> -	de = __getname();
> +	de = kmem_cache_zalloc(names_cachep, GFP_KERNEL);
>   	if (!de)
>   		return -ENOMEM;
> -	memset(de, 0, PATH_MAX);
>
>   	/* Mark rw ntfs as dirty. It will be cleared at umount. */
>   	ntfs_set_state(sbi, NTFS_DIRTY_DIRTY);
> @@ -1762,7 +1761,7 @@ int ntfs_unlink_inode(struct inode *dir, const struct dentry *dentry)
>   		return -EINVAL;
>
>   	/* Allocate PATH_MAX bytes. */
> -	de = __getname();
> +	de = kmem_cache_zalloc(names_cachep, GFP_KERNEL);
>   	if (!de)
>   		return -ENOMEM;
>
> --
> 2.39.5

The patch has been applied. Thanks for your work.

Regards,
Konstantin