Re: [PATCH] vme: Fix error not catched in fake_init()

[Chen Zhongjin]

Hi,

On 2022/12/5 20:31, Greg KH wrote:
> On Mon, Dec 05, 2022 at 04:48:05PM +0800, Chen Zhongjin wrote:
> > In fake_init(), __root_device_register() is possible to fail but it's
> > ignored, which can cause unregistering vme_root fail when exit.
> >
> >   general protection fault,
> >   probably for non-canonical address 0xdffffc000000008c
> >   KASAN: null-ptr-deref in range [0x0000000000000460-0x0000000000000467]
> >   RIP: 0010:root_device_unregister+0x26/0x60
> >   Call Trace:
> >    <TASK>
> >    __x64_sys_delete_module+0x34f/0x540
> >    do_syscall_64+0x38/0x90
> >    entry_SYSCALL_64_after_hwframe+0x63/0xcd
> >
> > Return error when __root_device_register() fails.
> >
> > Fixes: 658bcdae9c67 ("vme: Adding Fake VME driver")
> > Signed-off-by: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
> > ---
> >   drivers/staging/vme_user/vme_fake.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/staging/vme_user/vme_fake.c b/drivers/staging/vme_user/vme_fake.c
> > index dd646b0c531d..1ee432c223e2 100644
> > --- a/drivers/staging/vme_user/vme_fake.c
> > +++ b/drivers/staging/vme_user/vme_fake.c
> > @@ -1073,6 +1073,8 @@ static int __init fake_init(void)
> >   
> >   	/* We need a fake parent device */
> >   	vme_root = __root_device_register("vme", THIS_MODULE);
> This should be calling root_device_register() as well, not this version
> of the call.
Of course it should. Have sent another patch for it.

Thanks for your time!
Chen
> thanks,
>
> greg k-h