Hi
Am 10.09.24 um 09:22 schrieb Roger Pau Monné:
On Mon, Sep 09, 2024 at 10:09:16PM -0400, Jason Andryuk wrote:
From: Jason Andryuk jason.andryuk@amd.com
Probing xen-fbfront faults in video_is_primary_device(). The passed-in struct device is NULL since xen-fbfront doesn't assign it and the memory is kzalloc()-ed. Assign fb_info->device to avoid this.
This was exposed by the conversion of fb_is_primary_device() to video_is_primary_device() which dropped a NULL check for struct device.
Fixes: f178e96de7f0 ("arch: Remove struct fb_info from video helpers") Reported-by: Arthur Borsboom arthurborsboom@gmail.com Closes: https://lore.kernel.org/xen-devel/CALUcmUncX=LkXWeiSiTKsDY-cOe8QksWhFvcCneOK... Tested-by: Arthur Borsboom arthurborsboom@gmail.com CC: stable@vger.kernel.org Signed-off-by: Jason Andryuk jason.andryuk@amd.com
Reviewed-by: Roger Pau Monné roger.pau@citrix.com
The other option would be to re-instate the NULL check in video_is_primary_device()
I do think this is needed, or at least an explanation. The commit message in f178e96de7f0 doesn't mention anything about video_is_primary_device() not allowing being passed a NULL device (like it was possible with fb_is_primary_device()).
Otherwise callers of video_is_primary_device() would need to be adjusted to check for device != NULL.
The helper expects a non-NULL pointer. We might want to document this.
Best regards Thomas
Thanks, Roger.