Bug 2461504 (CVE-2026-31550)

Summary: CVE-2026-31550 kernel: pmdomain: bcm: bcm2835-power: Increase ASB control timeout
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's bcm2835-power component. An insufficient timeout during the ASB (Advanced System Bus) bridge control process, particularly under heavy system load, can prevent the V3D graphics processor from properly disabling. This can leave the V3D in an unstable state, potentially leading to system bus faults or complete system hangs, thereby impacting system availability.
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Description OSIDB Bzimport 2026-04-24 15:05:25 UTC 
In the Linux kernel, the following vulnerability has been resolved:

pmdomain: bcm: bcm2835-power: Increase ASB control timeout

The bcm2835_asb_control() function uses a tight polling loop to wait
for the ASB bridge to acknowledge a request. During intensive workloads,
this handshake intermittently fails for V3D's master ASB on BCM2711,
resulting in "Failed to disable ASB master for v3d" errors during
runtime PM suspend. As a consequence, the failed power-off leaves V3D in
a broken state, leading to bus faults or system hangs on later accesses.

As the timeout is insufficient in some scenarios, increase the polling
timeout from 1us to 5us, which is still negligible in the context of a
power domain transition. Also, replace the open-coded ktime_get_ns()/
cpu_relax() polling loop with readl_poll_timeout_atomic().
Comment 1 Keith Grant 2026-04-24 17:08:20 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042426-CVE-2026-31550-17d2@gregkh/T