[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <30d4e214-f53b-ac2d-e7f7-99bbd7b96b8f@samsung.com>
Date: Thu, 27 Jun 2019 10:23:27 +0300
From: Ilya Maximets <i.maximets@...sung.com>
To: Jakub Kicinski <jakub.kicinski@...ronome.com>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
bpf@...r.kernel.org, xdp-newbies@...r.kernel.org,
"David S. Miller" <davem@...emloft.net>,
Björn Töpel <bjorn.topel@...el.com>,
Magnus Karlsson <magnus.karlsson@...el.com>,
Jonathan Lemon <jonathan.lemon@...il.com>,
Daniel Borkmann <daniel@...earbox.net>
Subject: Re: [PATCH bpf v4 2/2] xdp: fix hang while unregistering device
bound to xdp socket
On 26.06.2019 21:34, Jakub Kicinski wrote:
> On Wed, 26 Jun 2019 21:15:15 +0300, Ilya Maximets wrote:
>> diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
>> index 267b82a4cbcf..56729e74cbea 100644
>> --- a/net/xdp/xdp_umem.c
>> +++ b/net/xdp/xdp_umem.c
>> @@ -140,34 +140,38 @@ int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
>> return err;
>> }
>>
>> -static void xdp_umem_clear_dev(struct xdp_umem *umem)
>> +void xdp_umem_clear_dev(struct xdp_umem *umem)
>> {
>> + bool lock = rtnl_is_locked();
>
> How do you know it's not just locked by someone else? You need to pass
> the locked state in if this is called from different paths, some of
> which already hold rtnl.
Oh. That's a shame. I need more sleep.
Thanks for spotting. I'll re-work this part.
Best regards, Ilya Maximets.
>
> Preferably factor the code which needs the lock out into a separate
> function like this:
>
> void __function()
> {
> do();
> the();
> things();
> under();
> the();
> lock();
> }
>
> void function()
> {
> rtnl_lock();
> __function();
> rtnl_unlock();
> }
>
>> struct netdev_bpf bpf;
>> int err;
>>
>> + if (!lock)
>> + rtnl_lock();
>
>
>
Powered by blists - more mailing lists