Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
Date:   Sun, 5 Jun 2022 21:19:49 -0700 (PDT)
From:   Hugh Dickins <hughd@google.com>
To:     Chen Wandun <chenwandun@huawei.com>
cc:     hughd@google.com, akpm@linux-foundation.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, willy@infradead.org,
        david@redhat.com, wangkefeng.wang@huawei.com
Subject: Re: [PATCH v3 1/3] mm/shmem: check return value of
 shmem_init_inodecache
In-Reply-To: <20220606034530.153505-2-chenwandun@huawei.com>
Message-ID: <bc6accde-cd1f-8c44-2d94-9e6131b659b3@google.com>
References: <20220606034530.153505-1-chenwandun@huawei.com> <20220606034530.153505-2-chenwandun@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Precedence: bulk

On Mon, 6 Jun 2022, Chen Wandun wrote:

> It will result in null pointer access if shmem_init_inodecache fail,
> so check return value of shmem_init_inodecache
> 
> Signed-off-by: Chen Wandun <chenwandun@huawei.com>

Thank you, but NAK.

It's a pity that you've been put to the trouble of sending a v3, sorry
about that: but if SLAB_PANIC no longer works, or panic() has taken to
returning, then that's what needs fixing, not shmem_init_inodecache().

Was this one supposed to be the bugfix?  And I'm afraid I don't care
for your "cleanups" in 2/3 and 3/3 either: a matter of taste, and our
tastes differ.

I'd rather not spend the time on these: maybe look for somewhere else
to change around than mm/shmem.c?  Or better, please help us all by
using your time to review the functional patches being posted.

Thanks,
Hugh

> ---
>  mm/shmem.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 12d45a03f7fc..7419ab219b97 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -3775,11 +3775,16 @@ static void shmem_init_inode(void *foo)
>  	inode_init_once(&info->vfs_inode);
>  }
>  
> -static void shmem_init_inodecache(void)
> +static int shmem_init_inodecache(void)
>  {
>  	shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
>  				sizeof(struct shmem_inode_info),
>  				0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
> +
> +	if (!shmem_inode_cachep)
> +		return -ENOMEM;
> +
> +	return 0;
>  }
>  
>  static void shmem_destroy_inodecache(void)
> @@ -3923,7 +3928,9 @@ void __init shmem_init(void)
>  {
>  	int error;
>  
> -	shmem_init_inodecache();
> +	error = shmem_init_inodecache();
> +	if (error)
> +		goto out2;
>  
>  	error = register_filesystem(&shmem_fs_type);
>  	if (error) {
> -- 
> 2.25.1