CVE-2026-31601

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

vfio/xe: Reorganize the init to decouple migration from reset

Attempting to issue reset on VF devices that don't support migration

leads to the following:

BUG: unable to handle page fault for address: 00000000000011f8

#PF: supervisor read access in kernel mode

#PF: error_code(0x0000) - not-present page

PGD 0 P4D 0

Oops: Oops: 0000 [#1] SMP NOPTI

CPU: 2 UID: 0 PID: 7443 Comm: xe_sriov_flr Tainted: G S U 7.0.0-rc1-lgci-xe-xe-4588-cec43d5c2696af219-nodebug+ #1 PREEMPT(lazy)

Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER

Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR4 RVP, BIOS RPLPFWI1.R00.4035.A00.2301200723 01/20/2023

RIP: 0010:xe_sriov_vfio_wait_flr_done+0xc/0x80 [xe]

Code: ff c3 cc cc cc cc 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 54 53 <83> bf f8 11 00 00 02 75 61 41 89 f4 85 f6 74 52 48 8b 47 08 48 89

RSP: 0018:ffffc9000f7c39b8 EFLAGS: 00010202

RAX: ffffffffa04d8660 RBX: ffff88813e3e4000 RCX: 0000000000000000

RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000

RBP: ffffc9000f7c39c8 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000000 R12: ffff888101a48800

R13: ffff88813e3e4150 R14: ffff888130d0d008 R15: ffff88813e3e40d0

FS: 00007877d3d0d940(0000) GS:ffff88890b6d3000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00000000000011f8 CR3: 000000015a762000 CR4: 0000000000f52ef0

PKRU: 55555554

Call Trace:

<TASK>

xe_vfio_pci_reset_done+0x49/0x120 [xe_vfio_pci]

pci_dev_restore+0x3b/0x80

pci_reset_function+0x109/0x140

reset_store+0x5c/0xb0

dev_attr_store+0x17/0x40

sysfs_kf_write+0x72/0x90

kernfs_fop_write_iter+0x161/0x1f0

vfs_write+0x261/0x440

ksys_write+0x69/0xf0

__x64_sys_write+0x19/0x30

x64_sys_call+0x259/0x26e0

do_syscall_64+0xcb/0x1500

? __fput+0x1a2/0x2d0

? fput_close_sync+0x3d/0xa0

? __x64_sys_close+0x3e/0x90

? x64_sys_call+0x1b7c/0x26e0

? do_syscall_64+0x109/0x1500

? __task_pid_nr_ns+0x68/0x100

? __do_sys_getpid+0x1d/0x30

? x64_sys_call+0x10b5/0x26e0

? do_syscall_64+0x109/0x1500

? putname+0x41/0x90

? do_faccessat+0x1e8/0x300

? __x64_sys_access+0x1c/0x30

? x64_sys_call+0x1822/0x26e0

? do_syscall_64+0x109/0x1500

? tick_program_event+0x43/0xa0

? hrtimer_interrupt+0x126/0x260

? irqentry_exit+0xb2/0x710

entry_SYSCALL_64_after_hwframe+0x76/0x7e

RIP: 0033:0x7877d5f1c5a4

Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 80 3d a5 ea 0e 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 55 48 89 e5 48 83 ec 20 48 89

RSP: 002b:00007fff48e5f908 EFLAGS: 00000202 ORIG_RAX: 0000000000000001

RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007877d5f1c5a4

RDX: 0000000000000001 RSI: 00007877d621b0c9 RDI: 0000000000000009

RBP: 0000000000000001 R08: 00005fb49113b010 R09: 0000000000000007

R10: 0000000000000000 R11: 0000000000000202 R12: 00007877d621b0c9

R13: 0000000000000009 R14: 00007fff48e5fac0 R15: 00007fff48e5fac0

</TASK>

This is caused by the fact that some of the xe_vfio_pci_core_device

members needed for handling reset are only initialized as part of

migration init.

Fix the problem by reorganizing the code to decouple VF init from

migration init.