CVE-2026-53331

/// Technical description

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

slimbus: qcom-ngd-ctrl: Avoid ABBA on tx_lock/ctrl->lock

During the SSR/PDR down notification the tx_lock is taken with the

intent to provide synchronization with active DMA transfers.

But during this period qcom_slim_ngd_down() is invoked, which ends up in

slim_report_absent(), which takes the slim_controller lock. In multiple

other codepaths these two locks are taken in the opposite order (i.e.

slim_controller then tx_lock).

The result is a lockdep splat, and a possible deadlock:

rprocctl/449 is trying to acquire lock:

ffff00009793e620 (&ctrl->lock){+.+.}-{4:4}, at: slim_report_absent (drivers/slimbus/core.c:322) slimbus

but task is already holding lock:

ffff00009793fb50 (&ctrl->tx_lock){+.+.}-{4:4}, at: qcom_slim_ngd_ssr_pdr_notify (drivers/slimbus/qcom-ngd-ctrl.c:1475) slim_qcom_ngd_ctrl

which lock already depends on the new lock.

Possible unsafe locking scenario:

CPU0

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References