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 <20231204123834.29247-2-pstanner@redhat.com>
Date:   Mon, 04 Dec 2023 14:35:55 +0100
From:   "Arnd Bergmann" <arnd@arndb.de>
To:     "Philipp Stanner" <pstanner@redhat.com>,
        "Bjorn Helgaas" <bhelgaas@google.com>,
        "Hanjun Guo" <guohanjun@huawei.com>, "Neil Brown" <neilb@suse.de>,
        "Kent Overstreet" <kent.overstreet@gmail.com>,
        "Jakub Kicinski" <kuba@kernel.org>,
        "Niklas Schnelle" <schnelle@linux.ibm.com>,
        "Uladzislau Koshchanka" <koshchanka@gmail.com>,
        "John Sanpe" <sanpeqf@gmail.com>,
        "Dave Jiang" <dave.jiang@intel.com>,
        "Masami Hiramatsu" <mhiramat@kernel.org>,
        "Kees Cook" <keescook@chromium.org>,
        "David Gow" <davidgow@google.com>,
        "Herbert Xu" <herbert@gondor.apana.org.au>,
        "Shuah Khan" <skhan@linuxfoundation.org>,
        "wuqiang.matt" <wuqiang.matt@bytedance.com>,
        "Yury Norov" <yury.norov@gmail.com>,
        "Jason Baron" <jbaron@akamai.com>,
        "Andrew Morton" <akpm@linux-foundation.org>,
        "Ben Dooks" <ben.dooks@codethink.co.uk>,
        "Danilo Krummrich" <dakr@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
        Linux-Arch <linux-arch@vger.kernel.org>, stable@vger.kernel.org,
        "Arnd Bergmann" <arnd@kernel.org>
Subject: Re: [PATCH v3 1/5] lib/pci_iomap.c: fix cleanup bugs in pci_iounmap()
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On Mon, Dec 4, 2023, at 13:38, Philipp Stanner wrote:
> pci_iounmap() in lib/pci_iomap.c is supposed to check whether an addre=
ss
> is within ioport-range IF the config specifies that ioports exist. If
> so, the port should be unmapped with ioport_unmap(). If not, it's a
> generic MMIO address that has to be passed to iounmap().
>
> The bugs are:
>   1. ioport_unmap() is missing entirely, so this function will never
>      actually unmap a port.
>   2. the #ifdef for the ioport-ranges accidentally also guards
>      iounmap(), potentially compiling an empty function. This would
>      cause the mapping to be leaked.
>
> Implement the missing call to ioport_unmap().
>
> Move the guard so that iounmap() will always be part of the function.
>
> CC: <stable@vger.kernel.org> # v5.15+
> Fixes: 316e8d79a095 ("pci_iounmap'2: Electric Boogaloo: try to make=20
> sense of it all")
> Reported-by: Danilo Krummrich <dakr@redhat.com>
> Suggested-by: Arnd Bergmann <arnd@kernel.org>
> Signed-off-by: Philipp Stanner <pstanner@redhat.com>
> ---
> In case someone wants to look into that and provide patches for kernels
> older than v5.15:
> Note that this patch only applies to v5.15+ =E2=80=93 the leaks, howev=
er, are
> older. I went through the log briefly and it seems f5810e5c32923 alrea=
dy
> contains them in asm-generic/io.h.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>