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serial: 8250: fix possible ISR soft lockup

Published Sep 24, 2026

Description

There are rare cases in which the host gets stuck in the ISR because it is flooded with messages during the startup phase.

The reason for the soft lockup in the ISR is the missing FIFO error IRQ (FIFOE) handling. Not handling it and reporting IRQ_HANDLED triggers the IRQ immediately again.

Fix this by adding a check for the FIFOE status and clearing the FIFO if no data is ready (DR).

This behavior was observed on an AM62L device which uses the OMAP 8250 driver. Fix it for all 8250 drivers, since the OMAP driver's special IRQ setup handling may trigger this behavior more frequently, but it is not ensured that other 8250 drivers aren't affected.

Affected products

Remediation

No remediation recorded yet.

Weaknesses (0)

No CWE recorded.

References (8)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner Linux
Published Sep 24, 2026
Updated Oct 3, 2026
Reserved Sep 24, 2026
NVD
Status Received
Modified Oct 3, 2026
Red Hat
Severity n/a
Public date n/a
ENISA EUVD
Assigner Linux
Published Sep 24, 2026
Updated Oct 3, 2026
Exploited since n/a
EUVD-2026-86079