From: Vasily Averin <vvs@virtuozzo.com>
To: Jeff Layton <jlayton@kernel.org>,
"J. Bruce Fields" <bfields@redhat.com>,
Chuck Lever <chuck.lever@oracle.com>
Cc: linux-nfs@vger.kernel.org
Subject: Re: [PATCH] nfsd: memory corruption in nfsd4_lock()
Date: Tue, 24 Mar 2020 01:12:33 +0300 [thread overview]
Message-ID: <e115cde6-315e-73ae-c89a-93eb5521e6c1@virtuozzo.com> (raw)
In-Reply-To: <7a3124cd2431eabe2495e0e8cd80068fe7261b1b.camel@kernel.org>
On 3/23/20 3:18 PM, Jeff Layton wrote:
> On Mon, 2020-03-23 at 10:55 +0300, Vasily Averin wrote:
>> New struct nfsd4_blocked_lock allocated in find_or_allocate_block()
>> does not initialised nbl_list and nbl_lru.
>> If conflock allocation fails rollback can call list_del_init()
>> access uninitialized fields and corrupt memory.
>>
>> Fixes: 76d348fadff5 ("nfsd: have nfsd4_lock use blocking locks for v4.1+ lock")
>> Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
>
> Good catch! Is there any reason not to just fix this by initializing the
> list_heads in find_or_allocate_block? That seems like it'd be a simpler
> fix.
>
Rollback in nfsd4_lock() is not optimal, I've tried to improve it too,
However I agree such improvement is not a simplest fix
and it anyway does not make whole rollback perfect.
I think it's better to re-send small fix for the found problem,
and prepare separate patches for rollback improvements,
Thank you,
Vasily Averin
next prev parent reply other threads:[~2020-03-23 22:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-23 7:55 [PATCH] nfsd: memory corruption in nfsd4_lock() Vasily Averin
2020-03-23 12:18 ` Jeff Layton
2020-03-23 22:12 ` Vasily Averin [this message]
2020-03-23 13:50 ` Chuck Lever
2020-03-23 15:09 ` J. Bruce Fields
2020-03-26 15:55 ` Chuck Lever
2020-03-27 4:50 ` [PATCH v2] " Vasily Averin
2020-03-30 10:22 ` Jeff Layton
2020-03-30 14:52 ` Chuck Lever
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