From: Vasily Averin <vvs@virtuozzo.com>
To: Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, Waiman Long <longman@redhat.com>,
Andreas Schwab <schwab@suse.de>
Subject: Re: [PATCH] ipc/util.c: sysvipc_find_ipc() incorrectly updates position index
Date: Fri, 8 May 2020 13:01:38 +0300 [thread overview]
Message-ID: <c89b587a-b570-2a11-3001-d1c8444f3a2f@virtuozzo.com> (raw)
In-Reply-To: <e25e5a42-159c-6bad-4f14-d70461a78b72@virtuozzo.com>
On 5/8/20 9:07 AM, Vasily Averin wrote:
> On 5/8/20 6:36 AM, Matthew Wilcox wrote:
>> On Thu, May 07, 2020 at 05:02:42PM -0700, Andrew Morton wrote:
>>> Here's how I resolved things. Please check?
>>>
>>> static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
>>> loff_t *new_pos)
>>> {
>>> unsigned long index = pos;
>>> struct kern_ipc_perm *ipc;
>>>
>>> rcu_read_lock();
>>> ipc = xa_find(&ids->ipcs, &index, ULONG_MAX, XA_PRESENT);
>>> if (ipc)
>>> ipc_lock_object(ipc);
>>> else
>>> rcu_read_unlock();
>>> *new_pos = pos + 1;
>>> return ipc;
>>> }
>>
>> Surely that should be '*new_pos = index + 1'? Or did I misunderstand
>> the reasoning behind the other patch?
>
> I'm not sure however it looks like xa_find() can return index < pos
it seems, I was wrong here.
So I'm agree with Matthew, '*new_pos = index + 1' should be used.
Thank you,
Vasily Averin
next prev parent reply other threads:[~2020-05-08 10:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-24 7:03 [PATCH 7/7] sysvipc_find_ipc should increase position index Vasily Averin
2020-01-24 16:26 ` Waiman Long
2020-02-25 6:35 ` Vasily Averin
2020-05-05 16:13 ` Andreas Schwab
2020-05-06 5:03 ` Vasily Averin
2020-05-06 6:25 ` [PATCH] ipc/util.c: sysvipc_find_ipc() incorrectly updates " Vasily Averin
2020-05-06 15:59 ` Waiman Long
2020-05-07 12:29 ` Vasily Averin
2020-05-08 0:02 ` Andrew Morton
2020-05-08 3:36 ` Matthew Wilcox
2020-05-08 6:07 ` Vasily Averin
2020-05-08 10:01 ` Vasily Averin [this message]
2020-05-12 9:21 ` Jiri Slaby
2020-05-12 15:45 ` Vasily Averin
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