linux-kernel - Re: [PATCH] block: Fix potential page reference leak in __bio_iov_iter_get

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Date:   Tue, 1 Sep 2020 17:09:05 +0100
From:   Christoph Hellwig <hch@...radead.org>
To:     Miaohe Lin <linmiaohe@...wei.com>
Cc:     axboe@...nel.dk, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] block: Fix potential page reference leak in
 __bio_iov_iter_get_pages()

On Tue, Sep 01, 2020 at 08:00:06AM -0400, Miaohe Lin wrote:
> When bio is full, __bio_iov_iter_get_pages() would return error directly
> while left page reference still held in pages. Release these references.
> Also advance the iov_iter according to what we have done successfully.
> 
> Fixes: 576ed9135489 ("block: use bio_add_page in bio_iov_iter_get_pages")
> Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>

The WARN_ON means something is fundamentally wrong here.  I think a few
leaked pages are the least of our problems in this case.