idpf: fix adapter NULL pointer dereference on reboot

In the Linux kernel, the following vulnerability has been resolved:

idpf: fix adapter NULL pointer dereference on reboot

With SRIOV enabled, idpf ends up calling into idpf_remove() twice.

First via idpf_shutdown() and then again when idpf_remove() calls into

sriov_disable(), because the VF devices use the idpf driver, hence the

same remove routine. When that happens, it is possible for the adapter

to be NULL from the first call to idpf_remove(), leading to a NULL

pointer dereference.

echo 1 > /sys/class/net/<netif>/device/sriov_numvfs

reboot

BUG: kernel NULL pointer dereference, address: 0000000000000020

...

RIP: 0010:idpf_remove+0x22/0x1f0 [idpf]

...

? idpf_remove+0x22/0x1f0 [idpf]

? idpf_remove+0x1e4/0x1f0 [idpf]

pci_device_remove+0x3f/0xb0

device_release_driver_internal+0x19f/0x200

pci_stop_bus_device+0x6d/0x90

pci_stop_and_remove_bus_device+0x12/0x20

pci_iov_remove_virtfn+0xbe/0x120

sriov_disable+0x34/0xe0

idpf_sriov_configure+0x58/0x140 [idpf]

idpf_remove+0x1b9/0x1f0 [idpf]

idpf_shutdown+0x12/0x30 [idpf]

pci_device_shutdown+0x35/0x60

device_shutdown+0x156/0x200

...

Replace the direct idpf_remove() call in idpf_shutdown() with

idpf_vc_core_deinit() and idpf_deinit_dflt_mbx(), which perform

the bulk of the cleanup, such as stopping the init task, freeing IRQs,

destroying the vports and freeing the mailbox. This avoids the calls to

sriov_disable() in addition to a small netdev cleanup, and destroying

workqueues, which don't seem to be required on shutdown.