Affected: Linux

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

usb: xhci_plat_remove: avoid NULL dereference

Since commit 4736ebd7fcaff1eb8481c140ba494962847d6e0a ("usb: host: xhci-plat: omit shared hcd if either root hub has no ports") xhci->shared_hcd can be NULL, which causes the following Oops on reboot:

[ 710.124450] systemd-shutdown[1]: Rebooting. [ 710.298861] xhci-hcd xhci-hcd.2.auto: remove, state 4 [ 710.304217] usb usb3: USB disconnect, device number 1 [ 710.317441] xhci-hcd xhci-hcd.2.auto: USB bus 3 deregistered [ 710.323280] xhci-hcd xhci-hcd.2.auto: remove, state 1 [ 710.328401] usb usb2: USB disconnect, device number 1 [ 710.333515] usb 2-3: USB disconnect, device number 2 [ 710.467649] xhci-hcd xhci-hcd.2.auto: USB bus 2 deregistered [ 710.475450] Unable to handle kernel NULL pointer dereference at virtual address 00000000000003b8 [ 710.484425] Mem abort info: [ 710.487265] ESR = 0x0000000096000004 [ 710.491060] EC = 0x25: DABT (current EL), IL = 32 bits [ 710.496427] SET = 0, FnV = 0 [ 710.499525] EA = 0, S1PTW = 0 [ 710.502716] FSC = 0x04: level 0 translation fault [ 710.507648] Data abort info: [ 710.510577] ISV = 0, ISS = 0x00000004 [ 710.514462] CM = 0, WnR = 0 [ 710.517480] user pgtable: 4k pages, 48-bit VAs, pgdp=00000008b0050000 [ 710.523976] [00000000000003b8] pgd=0000000000000000, p4d=0000000000000000 [ 710.530961] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 710.536551] Modules linked in: rfkill inp…