Subject: CVE-2021-47019: mt76: mt7921: fix possible invalid register access

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

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

mt76: mt7921: fix possible invalid register access

Disable the interrupt and synchronze for the pending irq handlers to ensure
the irq tasklet is not being scheduled after the suspend to avoid the
possible invalid register access acts when the host pcie controller is
suspended.

[17932.910534] mt7921e 0000:01:00.0: pci_pm_suspend+0x0/0x22c returned 0 after 21375 usecs
[17932.910590] pcieport 0000:00:00.0: calling pci_pm_suspend+0x0/0x22c @ 18565, parent: pci0000:00
[17932.910602] pcieport 0000:00:00.0: pci_pm_suspend+0x0/0x22c returned 0 after 8 usecs
[17932.910671] mtk-pcie 11230000.pcie: calling platform_pm_suspend+0x0/0x60 @ 22783, parent: soc
[17932.910674] mtk-pcie 11230000.pcie: platform_pm_suspend+0x0/0x60 returned 0 after 0 usecs

...

17933.615352] x1 : 00000000000d4200 x0 : ffffff8269ca2300
[17933.620666] Call trace:
[17933.623127]  mt76_mmio_rr+0x28/0xf0 [mt76]
[17933.627234]  mt7921_rr+0x38/0x44 [mt7921e]
[17933.631339]  mt7921_irq_tasklet+0x54/0x1d8 [mt7921e]
[17933.636309]  tasklet_action_common+0x12c/0x16c
[17933.640754]  tasklet_action+0x24/0x2c
[17933.644418]  __do_softirq+0x16c/0x344
[17933.648082]  irq_exit+0xa8/0xac
[17933.651224]  scheduler_ipi+0xd4/0x148
[17933.654890]  handle_IPI+0x164/0x2d4
[17933.658379]  gic_handle_irq+0x140/0x178
[17933.662216]  el1_irq+0xb8/0x180
[17933.665361]  cpuidle_enter_state+0xf8/0x204
[17933.669544]  cpuidle_enter+0x38/0x4c
[17933.673122]  do_idle+0x1a4/0x2a8
[17933.676352]  cpu_startup_entry+0x24/0x28
[17933.680276]  rest_init+0xd4/0xe0
[17933.683508]  arch_call_rest_init+0x10/0x18
[17933.687606]  start_kernel+0x340/0x3b4
[17933.691279] Code: aa0003f5 d503201f f953eaa8 8b344108 (b9400113)
[17933.697373] ---[ end trace a24b8e26ffbda3c5 ]---
[17933.767846] Kernel panic - not syncing: Fatal exception in interrupt

The Linux kernel CVE team has assigned CVE-2021-47019 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.12 with commit ffa1bf97425b and fixed in 5.12.4 with commit b13cbc536990
	Issue introduced in 5.12 with commit ffa1bf97425b and fixed in 5.13 with commit fe3fccde8870

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2021-47019
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/net/wireless/mediatek/mt76/mt7921/pci.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/b13cbc536990ff609afa878b6211cd6f6265ba60
	https://git.kernel.org/stable/c/fe3fccde8870764ba3e60610774bd7bc9f8faeff