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Subject: Re: [PATCH] mm/gup: Use put_user_page*() instead of put_page*()
To:     Bharath Vedartham <linux.bhar@gmail.com>,
        akpm@linux-foundation.org, ira.weiny@intel.com, jhubbard@nvidia.com
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Dimitri Sivanich <sivanich@sgi.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        Cornelia Huck <cohuck@redhat.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn.topel@intel.com>,
        Magnus Karlsson <magnus.karlsson@intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Jakub Kicinski <jakub.kicinski@netronome.com>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>,
        Enrico Weigelt <info@metux.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Alexios Zavras <alexios.zavras@intel.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Max Filippov <jcmvbkbc@gmail.com>,
        Matt Sickler <Matt.Sickler@daktronics.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Keith Busch <keith.busch@intel.com>,
        YueHaibing <yuehaibing@huawei.com>, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org,
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        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        netdev@vger.kernel.org, bpf@vger.kernel.org,
        xdp-newbies@vger.kernel.org
References: <1563131456-11488-1-git-send-email-linux.bhar@gmail.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <018ee3d1-e2f0-ca12-9f63-945056c09985@kernel.dk>
Date:   Sun, 14 Jul 2019 20:33:57 -0600
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On 7/14/19 1:08 PM, Bharath Vedartham wrote:
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 4ef62a4..b4a4549 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -2694,10 +2694,9 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
>   			 * if we did partial map, or found file backed vmas,
>   			 * release any pages we did get
>   			 */
> -			if (pret > 0) {
> -				for (j = 0; j < pret; j++)
> -					put_page(pages[j]);
> -			}
> +			if (pret > 0)
> +				put_user_pages(pages, pret);
> +
>   			if (ctx->account_mem)
>   				io_unaccount_mem(ctx->user, nr_pages);
>   			kvfree(imu->bvec);

You handled just the failure case of the buffer registration, but not
the actual free in io_sqe_buffer_unregister().

-- 
Jens Axboe