CVE-2025-68746

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

spi: tegra210-quad: Fix timeout handling

When the CPU that the QSPI interrupt handler runs on (typically CPU 0) is excessively busy, it can lead to rare cases of the IRQ thread not running before the transfer timeout is reached.

While handling the timeouts, any pending transfers are cleaned up and the message that they correspond to is marked as failed, which leaves the curr_xfer field pointing at stale memory.

To avoid this, clear curr_xfer to NULL upon timeout and check for this condition when the IRQ thread is finally run.

While at it, also make sure to clear interrupts on failure so that new interrupts can be run.

A better, more involved, fix would move the interrupt clearing into a hard IRQ handler. Ideally we would also want to signal that the IRQ thread no longer needs to be run after the timeout is hit to avoid the extra check for a valid transfer.

A flaw was found in the Linux kernel's Tegra210 QSPI controller driver (spi: tegra210-quad). When the CPU that services the QSPI interrupt handler (typically CPU 0) is excessively busy, the IRQ thread may not run before a SPI transfer timeout is reached. Timeout handling cleans up pending transfers and marks the corresponding message as failed, which leaves the driver's curr_xfer pointer referencing stale memory; when the IRQ thread finally runs, it may act on this stale transfer. Interrupts are also not cleared on failure, which can prevent new interrupts from being handled. A low-privileged local user on an affected system could potentially trigger this rare race condition under heavy CPU load, causing the kernel to act on stale memory and resulting in a denial of service of SPI transfers on the affected QSPI controller.

Red Hat rates this flaw as LOW severity (CVSS 3.3, AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L) because exploitation requires local access, low privileges, and a rare race condition, and the impact is limited to availability with no confidentiality or integrity impact. This differs from the upstream CVEORG score of 7.8, which assumes a broader scope of impact.

In Red Hat Enterprise Linux 9 and Red Hat Enterprise Linux 10 (kernel and kernel-rt packages), this flaw is affected and the fix is currently deferred: the issue is a rare, low-severity race condition whose availability-only impact is limited to systems using the affected Tegra210 QSPI controller hardware, so it does not warrant an immediate update. The residual risk for affected systems is a possible denial of service of SPI transfers under heavy CPU load on the interrupt-handling CPU. Red Hat Enterprise Linux 6, 7, and 8 (including ELS and z-stream updates) and Red Hat In-Vehicle OS are not affected because the vulnerable code is not present.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.