linux-kernel - Re: [PATCH 1/1] fbdev: hyperv_fb: iounmap() the correct memory when removing a device

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Message-ID: <Z6wHDw8BssJyQHiM@liuwe-devbox-debian-v2>
Date: Wed, 12 Feb 2025 02:27:27 +0000
From: Wei Liu <wei.liu@...nel.org>
To: mhklinux@...look.com
Cc: haiyangz@...rosoft.com, wei.liu@...nel.org, decui@...rosoft.com,
	deller@....de, weh@...rosoft.com, dri-devel@...ts.freedesktop.org,
	linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-hyperv@...r.kernel.org
Subject: Re: [PATCH 1/1] fbdev: hyperv_fb: iounmap() the correct memory when
 removing a device

On Sun, Feb 09, 2025 at 03:52:52PM -0800, mhkelley58@...il.com wrote:
> From: Michael Kelley <mhklinux@...look.com>
> 
> When a Hyper-V framebuffer device is removed, or the driver is unbound
> from a device, any allocated and/or mapped memory must be released. In
> particular, MMIO address space that was mapped to the framebuffer must
> be unmapped. Current code unmaps the wrong address, resulting in an
> error like:
> 
> [ 4093.980597] iounmap: bad address 00000000c936c05c
> 
> followed by a stack dump.
> 
> Commit d21987d709e8 ("video: hyperv: hyperv_fb: Support deferred IO for
> Hyper-V frame buffer driver") changed the kind of address stored in
> info->screen_base, and the iounmap() call in hvfb_putmem() was not
> updated accordingly.
> 
> Fix this by updating hvfb_putmem() to unmap the correct address.
> 
> Fixes: d21987d709e8 ("video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver")
> Signed-off-by: Michael Kelley <mhklinux@...look.com>

Applied to hyperv-fixes. Thanks.