On Mon, Dec 4, 2023, at 13:38, Philipp Stanner wrote:
> pci_iounmap() in lib/pci_iomap.c is supposed to check whether an address
> 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@xxxxxxxxxxxxxxx> # v5.15+
> Fixes: 316e8d79a095 ("pci_iounmap'2: Electric Boogaloo: try to make
> sense of it all")
> Reported-by: Danilo Krummrich <dakr@xxxxxxxxxx>
> Suggested-by: Arnd Bergmann <arnd@xxxxxxxxxx>
> Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx>
> ---
> 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+ – the leaks, however, are
> older. I went through the log briefly and it seems f5810e5c32923 already
> contains them in asm-generic/io.h.
Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
