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Date:   Wed, 19 Apr 2023 10:12:42 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Jesper Dangaard Brouer <jbrouer@redhat.com>
Cc:     Lorenzo Bianconi <lorenzo@kernel.org>, brouer@redhat.com,
        Eric Dumazet <edumazet@google.com>, netdev@vger.kernel.org,
        hawk@kernel.org, ilias.apalodimas@linaro.org, davem@davemloft.net,
        pabeni@redhat.com, bpf@vger.kernel.org,
        lorenzo.bianconi@redhat.com, nbd@nbd.name,
        Toke Hoiland Jorgensen <toke@redhat.com>
Subject: Re: issue with inflight pages from page_pool
Message-ID: <20230419101242.44f2d143@kernel.org>
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On Wed, 19 Apr 2023 17:36:20 +0200 Jesper Dangaard Brouer wrote:
> This reminds me that Jakub's recent defer patches returning pages
> 'directly' to the page_pool alloc-cache, will actually result in this
> kind of bug.  This is because page_pool_destroy() assumes that pages
> cannot be returned to alloc-cache, as driver will have "disconnected" RX
> side.  We need to address this bug separately. 

Mm, I think you're right. The NAPI can get restarted with a different
page pool and the old page pool will still think it's in use.