CVE-2024-56760
PCI/MSI: Handle lack of irqdomain gracefully
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PCI/MSI: Handle lack of irqdomain gracefully
In the Linux kernel, the following vulnerability has been resolved: PCI/MSI: Handle lack of irqdomain gracefully Alexandre observed a warning emitted from pci_msi_setup_msi_irqs() on a RISCV platform which does not provide PCI/MSI support: WARNING: CPU: 1 PID: 1 at drivers/pci/msi/msi.h:121 pci_msi_setup_msi_irqs+0x2c/0x32 __pci_enable_msix_range+0x30c/0x596 pci_msi_setup_msi_irqs+0x2c/0x32 pci_alloc_irq_vectors_affinity+0xb8/0xe2 RISCV uses hierarchical interrupt domains and correctly does not implement the legacy fallback. The warning triggers from the legacy fallback stub. That warning is bogus as the PCI/MSI layer knows whether a PCI/MSI parent domain is associated with the device or not. There is a check for MSI-X, which has a legacy assumption. But that legacy fallback assumption is only valid when legacy support is enabled, but otherwise the check should simply return -ENOTSUPP. Loongarch tripped over the same problem and blindly enabled legacy support without implementing the legacy fallbacks. There are weak implementations which return an error, so the problem was papered over. Correct pci_msi_domain_supports() to evaluate the legacy mode and add the missing supported check into the MSI enable path to complete it.
Reserved 2024-12-29 | Published 2025-01-06 | Updated 2025-01-20 | Assigner Linuxgit.kernel.org/...c/b1f7476e07b93d65a1a3643dcb4a7bed80d4328d
git.kernel.org/...c/aed157301c659a48f5564cc4568cf0e5c8831af0
git.kernel.org/...c/a60b990798eb17433d0283788280422b1bd94b18
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