CVE-2024-57889

CVE Details

Release Date:	2025-01-15
Impact:	Low	What is this?

Description

In the Linux kernel, the following vulnerability has been resolved: pinctrl: mcp23s08: Fix sleeping in atomic context due to regmap locking If a device uses MCP23xxx IO expander to receive IRQs, the following bug can happen: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:283 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, ... preempt_count: 1, expected: 0 ... Call Trace: ... __might_resched+0x104/0x10e __might_sleep+0x3e/0x62 mutex_lock+0x20/0x4c regmap_lock_mutex+0x10/0x18 regmap_update_bits_base+0x2c/0x66 mcp23s08_irq_set_type+0x1ae/0x1d6 __irq_set_trigger+0x56/0x172 __setup_irq+0x1e6/0x646 request_threaded_irq+0xb6/0x160 ... We observed the problem while experimenting with a touchscreen driver which used MCP23017 IO expander (I2C). The regmap in the pinctrl-mcp23s08 driver uses a mutex for protection from concurrent accesses, which is the default for regmaps without .fast_io, .disable_locking, etc. mcp23s08_irq_set_type() calls regmap_update_bits_base(), and the latter locks the mutex. However, __setup_irq() locks desc->lock spinlock before calling these functions. As a result, the system tries to lock the mutex whole holding the spinlock. It seems, the internal regmap locks are not needed in this driver at all. mcp->lock seems to protect the regmap from concurrent accesses already, except, probably, in mcp_pinconf_get/set. mcp23s08_irq_set_type() and mcp23s08_irq_mask/unmask() are called under chip_bus_lock(), which calls mcp23s08_irq_bus_lock(). The latter takes mcp->lock and enables regmap caching, so that the potentially slow I2C accesses are deferred until chip_bus_unlock(). The accesses to the regmap from mcp23s08_probe_one() do not need additional locking. In all remaining places where the regmap is accessed, except mcp_pinconf_get/set(), the driver already takes mcp->lock. This patch adds locking in mcp_pinconf_get/set() and disables internal locking in the regmap config. Among other things, it fixes the sleeping in atomic context described above.

See more information about CVE-2024-57889 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	5.5
Vector String:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	Low
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	None
Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 10 (kernel-uek)	ELSA-2025-20480	2025-07-17
Oracle Linux version 9 (kernel-uek)	ELSA-2025-20480	2025-07-17