idpf: fix adapter NULL pointer dereference on reboot

Summary

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.