CVE-2022-49613

published 2025-02-26

CVE-2022-49613: In the Linux kernel, the following vulnerability has been resolved: serial: 8250: Fix PM usage_count for console handover When console is enabled…

Priority P4 19 medium 5.5 CVSS 3.1

AV L AC L PR L UI N S U C N I N A H

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

serial: 8250: Fix PM usage_count for console handover

When console is enabled, univ8250_console_setup() calls
serial8250_console_setup() before .dev is set to uart_port. Therefore,
it will not call pm_runtime_get_sync(). Later, when the actual driver
is going to take over univ8250_console_exit() is called. As .dev is
already set, serial8250_console_exit() makes pm_runtime_put_sync() call
with usage count being zero triggering PM usage count warning
(extra debug for univ8250_console_setup(), univ8250_console_exit(), and
serial8250_register_ports()):

[ 0.068987] univ8250_console_setup ttyS0 nodev
[ 0.499670] printk: console [ttyS0] enabled
[ 0.717955] printk: console [ttyS0] printing thread started
[ 1.960163] serial8250_register_ports assigned dev for ttyS0
[ 1.976830] printk: console [ttyS0] disabled
[ 1.976888] printk: console [ttyS0] printing thread stopped
[ 1.977073] univ8250_console_exit ttyS0 usage:0
[ 1.977075] serial8250 serial8250: Runtime PM usage count underflow!
[ 1.977429] dw-apb-uart.6: ttyS0 at MMIO 0x4010006000 (irq = 33, base_baud = 115200) is a 16550A
[ 1.977812] univ8250_console_setup ttyS0 usage:2
[ 1.978167] printk: console [ttyS0] printing thread started
[ 1.978203] printk: console [ttyS0] enabled

To fix the issue, call pm_runtime_get_sync() in
serial8250_register_ports() as soon as .dev is set for an uart_port
if it has console enabled.

This problem became apparent only recently because 82586a721595 ("PM:
runtime: Avoid device usage count underflows") added the warning
printout. I confirmed this problem also occurs with v5.18 (w/o the
warning printout, obviously).

Affected

14 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 5.18.14-1 (bookworm)	linux 5.18.14-1 (bookworm)
linux	linux	—	—
linux	linux	>= bedb404e91bb2908d9921fc736a518a9d89525fc < d9cb6fabc90102f9e61fe35bd0160db88f4f53b4	d9cb6fabc90102f9e61fe35bd0160db88f4f53b4
linux	linux	>= bedb404e91bb2908d9921fc736a518a9d89525fc < 190ce5cdc55d1b66ea582ac2be6fd5a72e3cc486	190ce5cdc55d1b66ea582ac2be6fd5a72e3cc486
linux	linux	>= bedb404e91bb2908d9921fc736a518a9d89525fc < 5df66302f03f87ae8953785a882d78e911f00c55	5df66302f03f87ae8953785a882d78e911f00c55
linux	linux	>= bedb404e91bb2908d9921fc736a518a9d89525fc < f9b11229b79c0fb2100b5bb4628a101b1d37fbf6	f9b11229b79c0fb2100b5bb4628a101b1d37fbf6
linux	linux_kernel	—	—
linux	linux_kernel	>= 0 < 5.10.136-1	5.10.136-1
linux	linux_kernel	>= 0 < 5.18.14-1	5.18.14-1
linux	linux_kernel	>= 0 < 5.18.14-1	5.18.14-1
linux	linux_kernel	>= 0 < 5.18.14-1	5.18.14-1
linux	linux_kernel	>= 5.11 < 5.15.56	5.15.56
linux	linux_kernel	>= 5.16 < 5.18.13	5.18.13
linux	linux_kernel	>= 5.7 < 5.10.132	5.10.132

CVSS provenance

nvd v3.1 5.5 MEDIUM CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv 5.5 MEDIUM

vendor_debian 5.5 MEDIUM

vendor_redhat 5.5 MEDIUM

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