CVE-2025-37905: firmware: arm_scmi: Balance device refcount when destroying devices

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-20 · updated 2026-06-17
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Balance device refcount when destroying devices Using device_find_child() to lookup the proper SCMI device to destroy causes an unbalance in device refcount, since device_find_child() calls an implicit get_device(): this, in turns, inhibits the call of the provided release methods upon devices destruction. As a consequence, one of the structures that is not freed properly upon destruction is the internal struct device_private dev->p populated by the drivers subsystem core. KMemleak detects this situation since loading/unloding some SCMI driver causes related devices to be created/destroyed without calling any device_release method. unreferenced object 0xffff00000f583800 (size 512): comm "insmod", pid 227, jiffies 4294912190 hex dump (first 32 bytes): 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... ff ff ff ff ff ff ff ff 60 36 1d 8a 00 80 ff ff ........`6...... backtrace (crc 114e2eed): kmemleak_alloc+0xbc/0xd8 __kmalloc_cache_noprof+0x2dc/0x398 device_add+0x954/0x12d0 device_register+0x28/0x40 __scmi_device_create.part.0+0x1bc/0x380 scmi_device_create+0x2d0/0x390 scmi_create_protocol_devices+0x74/0xf8 scmi_device_request_notifier+0x1f8/0x2a8 notifier_call_chain+0x110/0x3b0 blocking_notifier_call_chain+0x70/0xb0 scmi_driver_register+0x350/0x7f0 0xffff80000a3b3038 do_one_initcall+0x12c/0x730 do_init_module+0x1dc/0x640 load_module+0x4b20/0x5b70 init_module_from_file+0xec/0x158 $ ./scripts/faddr2line ./vmlinux device_add+0x954/0x12d0 device_add+0x954/0x12d0: kmalloc_noprof at include/linux/slab.h:901 (inlined by) kzalloc_noprof at include/linux/slab.h:1037 (inlined by) device_private_init at drivers/base/core.c:3510 (inlined by) device_add at drivers/base/core.c:3561 Balance device refcount by issuing a put_device() on devices found via device_find_child().

Affected products

Debian Linux: 11.0
Linux kernel: from 5.13 before 5.15.182; from 5.16 before 6.1.138; from 6.2 before 6.6.90; from 6.7 before 6.12.28; from 6.13 before 6.14.6; 6.15-rc1, 6.15-rc2, 6.15-rc3, 6.15-rc4, 6.15-rc5 — fixed in 5.15.182, 6.1.138, 6.12.28, 6.14.6, 6.6.90

How to fix

Upgrade to a fixed version: Linux kernel 5.15.182, 6.1.138, 6.12.28, 6.14.6. Check the vendor advisory for mitigations.

References

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