From: David Miller <davem@davemloft.net>
To: vkuznets@redhat.com
Cc: sthemmin@microsoft.com, netdev@vger.kernel.org,
devel@linuxdriverproject.org, linux-kernel@vger.kernel.org,
kys@microsoft.com, haiyangz@microsoft.com
Subject: Re: [PATCH net-next] hv_netvsc: fix a race between netvsc_send() and netvsc_init_buf()
Date: Thu, 20 Oct 2016 14:03:00 -0400 (EDT) [thread overview]
Message-ID: <20161020.140300.122827393647670926.davem@davemloft.net> (raw)
In-Reply-To: <8737jr1k07.fsf@vitty.brq.redhat.com>
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Thu, 20 Oct 2016 10:51:04 +0200
> Stephen Hemminger <sthemmin@microsoft.com> writes:
>
>> Do we need ACCESS_ONCE() here to avoid check/use issues?
>>
>
> I think we don't: this is the only place in the function where we read
> the variable so we'll get normal read. We're not trying to syncronize
> with netvsc_init_buf() as that would require locking, if we read stale
> NULL value after it was already updated on a different CPU we're fine,
> we'll just return -EAGAIN.
The concern is if we race with netvsc_destroy_buf() and this pointer
becomes NULL after the test you are adding.
next prev parent reply other threads:[~2016-10-20 18:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-19 13:53 [PATCH net-next] hv_netvsc: fix a race between netvsc_send() and netvsc_init_buf() Vitaly Kuznetsov
2016-10-20 8:36 ` Stephen Hemminger
2016-10-20 8:51 ` Vitaly Kuznetsov
2016-10-20 18:03 ` David Miller [this message]
2016-10-21 11:15 ` Vitaly Kuznetsov
2016-10-21 14:52 ` David Miller
2016-10-21 15:17 ` Vitaly Kuznetsov
2016-10-21 15:27 ` David Miller
2016-10-21 15:28 ` David Miller
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