CVE-2023-52492: dmaengine: fix NULL pointer in channel unregistration function

Severity: medium (CVSS 4.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-03-11 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: dmaengine: fix NULL pointer in channel unregistration function __dma_async_device_channel_register() can fail. In case of failure, chan->local is freed (with free_percpu()), and chan->local is nullified. When dma_async_device_unregister() is called (because of managed API or intentionally by DMA controller driver), channels are unconditionally unregistered, leading to this NULL pointer: [ 1.318693] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000d0 [...] [ 1.484499] Call trace: [ 1.486930] device_del+0x40/0x394 [ 1.490314] device_unregister+0x20/0x7c [ 1.494220] __dma_async_device_channel_unregister+0x68/0xc0 Look at dma_async_device_register() function error path, channel device unregistration is done only if chan->local is not NULL. Then add the same condition at the beginning of __dma_async_device_channel_unregister() function, to avoid NULL pointer issue whatever the API used to reach this function.

Affected products

Debian Linux: 10.0
Linux kernel: from 5.6 before 5.10.210; from 5.11 before 5.15.149; from 5.16 before 6.1.76; from 6.2 before 6.6.15; from 6.7 before 6.7.3 — fixed in 5.10.210, 5.15.149, 6.1.76, 6.6.15, 6.7.3

How to fix

Upgrade to a fixed version: Linux kernel 5.10.210, 5.15.149, 6.1.76, 6.6.15. Check the vendor advisory for mitigations.

References

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