CVE-2025-40076
Description
In the Linux kernel, the following vulnerability has been resolved:
PCI: rcar-host: Pass proper IRQ domain to generic_handle_domain_irq()
Starting with commit dd26c1a23fd5 ("PCI: rcar-host: Switch to msi_create_parent_irq_domain()"), the MSI parent IRQ domain is NULL because the object of type struct irq_domain_info passed to:
msi_create_parent_irq_domain() -> irq_domain_instantiate()() -> __irq_domain_instantiate()
has no reference to the parent IRQ domain. Using msi->domain->parent as an argument for generic_handle_domain_irq() leads to below error:
"Unable to handle kernel NULL pointer dereference at virtual address"
This error was identified while switching the upcoming RZ/G3S PCIe host controller driver to msi_create_parent_irq_domain() (which was using a similar pattern to handle MSIs (see link section)), but it was not tested on hardware using the pcie-rcar-host controller driver due to lack of hardware.
[mani: reworded subject and description]
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
NULL pointer dereference in PCI rcar-host driver due to missing IRQ domain leads to kernel panic.
Vulnerability
In the Linux kernel's PCI rcar-host driver, a NULL pointer dereference occurs when handling MSI interrupts. The issue arises because the MSI parent IRQ domain is not properly set, causing generic_handle_domain_irq() to access a NULL pointer.
Exploitation
An attacker with local access or the ability to trigger MSI interrupts on a system using the pcie-rcar-host controller driver could exploit this bug. The error manifests as an "Unable to handle kernel NULL pointer dereference" and leads to a system crash.
Impact
Successful exploitation results in a denial of service (kernel panic). The vulnerability affects the Linux kernel, potentially impacting systems with Renesas R-Car PCIe controllers.
Mitigation
The fix was applied in Linux kernel stable commit e8e21aaf5d34 [1]. Users should update to the patched kernel version to mitigate the issue.
AI Insight generated on May 19, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
1Patches
2e8e21aaf5d34d3fee10e40a9Vulnerability mechanics
Generated on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
2News mentions
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