From: Ilya Maximets <i.maximets@samsung.com>
To: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
bpf@vger.kernel.org, xdp-newbies@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
"Björn Töpel" <bjorn.topel@intel.com>,
"Magnus Karlsson" <magnus.karlsson@intel.com>,
"Jonathan Lemon" <jonathan.lemon@gmail.com>,
"Daniel Borkmann" <daniel@iogearbox.net>
Subject: Re: [PATCH bpf v4 2/2] xdp: fix hang while unregistering device bound to xdp socket
Date: Thu, 27 Jun 2019 10:23:27 +0300 [thread overview]
Message-ID: <30d4e214-f53b-ac2d-e7f7-99bbd7b96b8f@samsung.com> (raw)
In-Reply-To: <20190626113427.761cc845@cakuba.netronome.com>
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();
>
>
>
prev parent reply other threads:[~2019-06-27 7:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20190626181520eucas1p1817d31d958b8755600f0745e92edef5a@eucas1p1.samsung.com>
2019-06-26 18:15 ` [PATCH bpf v4 0/2] xdp: fix hang while unregistering device bound to xdp socket Ilya Maximets
[not found] ` <CGME20190626181525eucas1p2d0f467c8ba7504b7dcc639712575032e@eucas1p2.samsung.com>
2019-06-26 18:15 ` [PATCH bpf v4 1/2] xdp: hold device for umem regardless of zero-copy mode Ilya Maximets
[not found] ` <CGME20190626181528eucas1p190f20427a1d2a64f2efa6cedcfac0826@eucas1p1.samsung.com>
2019-06-26 18:15 ` [PATCH bpf v4 2/2] xdp: fix hang while unregistering device bound to xdp socket Ilya Maximets
2019-06-26 18:34 ` Jakub Kicinski
2019-06-27 7:23 ` Ilya Maximets [this message]
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