From: Paolo Abeni <pabeni@redhat.com>
To: Yunsheng Lin <yunshenglin0825@gmail.com>,
Yunsheng Lin <linyunsheng@huawei.com>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: liuyonglong@huawei.com, fanghaiqing@huawei.com,
zhangkun09@huawei.com, Robin Murphy <robin.murphy@arm.com>,
Alexander Duyck <alexander.duyck@gmail.com>,
IOMMU <iommu@lists.linux.dev>, Wei Fang <wei.fang@nxp.com>,
Shenwei Wang <shenwei.wang@nxp.com>,
Clark Wang <xiaoning.wang@nxp.com>,
Eric Dumazet <edumazet@google.com>,
Tony Nguyen <anthony.l.nguyen@intel.com>,
Przemek Kitszel <przemyslaw.kitszel@intel.com>,
Alexander Lobakin <aleksander.lobakin@intel.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Saeed Mahameed <saeedm@nvidia.com>,
Leon Romanovsky <leon@kernel.org>,
Tariq Toukan <tariqt@nvidia.com>, Felix Fietkau <nbd@nbd.name>,
Lorenzo Bianconi <lorenzo@kernel.org>,
Ryder Lee <ryder.lee@mediatek.com>,
Shayne Chen <shayne.chen@mediatek.com>,
Sean Wang <sean.wang@mediatek.com>, Kalle Valo <kvalo@kernel.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com>,
Andrew Morton <akpm@linux-foundation.org>,
imx@lists.linux.dev, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
bpf@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-wireless@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, linux-mm@kvack.org,
davem@davemloft.net, kuba@kernel.org
Subject: Re: [PATCH net v2 2/2] page_pool: fix IOMMU crash when driver has already unbound
Date: Wed, 2 Oct 2024 09:37:54 +0200 [thread overview]
Message-ID: <4316fa2d-8dd8-44f2-b211-4b2ef3200d75@redhat.com> (raw)
In-Reply-To: <33f23809-abec-4d39-ab80-839dc525a2e6@gmail.com>
Hi,
On 10/2/24 04:34, Yunsheng Lin wrote:
> On 10/1/2024 9:32 PM, Paolo Abeni wrote:
>> Is the problem only tied to VFs drivers? It's a pity all the page_pool
>> users will have to pay a bill for it...
>
> I am afraid it is not only tied to VFs drivers, as:
> attempting DMA unmaps after the driver has already unbound may leak
> resources or at worst corrupt memory.
>
> Unloading PFs driver might cause the above problems too, I guess the
> probability of crashing is low for the PF as PF can not be disable
> unless it can be hot-unplug'ed, but the probability of leaking resources
> behind the dma mapping might be similar.
Out of sheer ignorance, why/how the refcount acquired by the page pool
on the device does not prevent unloading?
I fear the performance impact could be very high: AFICS, if the item
array become fragmented, insertion will take linar time, with the quite
large item_count/pool size. If so, it looks like a no-go.
I fear we should consider blocking the device removal until all the
pages are returned/unmapped ?!? (I hope that could be easier/faster)
/P
next prev parent reply other threads:[~2024-10-02 7:38 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240925075707.3970187-1-linyunsheng@huawei.com>
2024-09-25 7:57 ` [PATCH net v2 2/2] page_pool: fix IOMMU crash when driver has already unbound Yunsheng Lin
2024-09-26 18:15 ` Mina Almasry
2024-09-27 3:57 ` Yunsheng Lin
2024-09-27 5:54 ` Mina Almasry
2024-09-27 7:25 ` Yunsheng Lin
2024-09-27 9:21 ` Ilias Apalodimas
2024-09-27 9:49 ` Yunsheng Lin
2024-09-27 9:58 ` Ilias Apalodimas
2024-09-27 11:29 ` Yunsheng Lin
2024-09-28 7:34 ` Ilias Apalodimas
2024-09-29 2:44 ` Yunsheng Lin
2024-09-30 8:09 ` Ilias Apalodimas
2024-09-30 8:38 ` Yunsheng Lin
2024-10-01 13:32 ` Paolo Abeni
2024-10-02 2:34 ` Yunsheng Lin
2024-10-02 7:37 ` Paolo Abeni [this message]
2024-10-02 8:23 ` Ilias Apalodimas
2024-10-05 12:38 ` Yunsheng Lin
2024-10-02 6:46 ` Ilias Apalodimas
2024-10-02 6:51 ` Ilias Apalodimas
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