Bug 2525404 (CVE-2026-80620)
| Summary: | CVE-2026-80620 kernel: Revert "PCI/MSI: Unmap MSI-X region on error" | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | rhel-process-autobot, watson-tool-maintainers |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in the Linux kernel. During the error handling of Message Signaled Interrupts eXtended (MSI-X) region setup, the kernel attempts to unmap an already freed memory region. This double unmap operation on a null pointer can lead to a kernel warning or crash. A local attacker could potentially exploit this vulnerability to cause a system-wide Denial of Service (DoS).
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
In the Linux kernel, the following vulnerability has been resolved: Revert "PCI/MSI: Unmap MSI-X region on error" This reverts commit 1a8d4c6ecb4c81261bcdf13556abd4a958eca202. Commit 1a8d4c6ecb4c ("PCI/MSI: Unmap MSI-X region on error") added an iounmap(dev->msix_base) on the error path of msix_capability_init() to release the MSI-X region when msix_setup_interrupts() fails. When msix_setup_interrupts() fails, the call chain is: msix_setup_interrupts() -> __msix_setup_interrupts() struct pci_dev *dev __free(free_msi_irqs) = __dev; ... return ret; // __free cleanup fires on error The __free(free_msi_irqs) cleanup calls pci_free_msi_irqs(), which already handles the unmap: void pci_free_msi_irqs(struct pci_dev *dev) { pci_msi_teardown_msi_irqs(dev); if (dev->msix_base) { iounmap(dev->msix_base); // already unmapped here dev->msix_base = NULL; // and set to NULL } } So dev->msix_base is unmapped and set to NULL before msix_setup_interrupts() returns to msix_capability_init(). The "goto out_unmap" introduced by commit 1a8d4c6ecb4c ("PCI/MSI: Unmap MSI-X region on error") then calls iounmap() a second time on a NULL pointer. This was reproduced on Intel Emerald Rapids (192 CPUs) while running tools/testing/selftests/kexec/test_kexec_jump.sh: WARNING: CPU#44 at iounmap+0x2a/0xe0 RIP: 0010:iounmap+0x2a/0xe0 RDI: 0000000000000000 Call Trace: msix_capability_init+0x317/0x3f0 __pci_enable_msix_range+0x21d/0x2c0 pci_alloc_irq_vectors_affinity+0xa9/0x130 nvme_setup_io_queues+0x2a8/0x420 [nvme] nvme_reset_work+0x151/0x340 [nvme] ... RDI=0 confirms iounmap() is called with NULL. Restore the original "goto out_disable" and leave the unmap to the existing __free(free_msi_irqs) cleanup.