Bug 2513262 (CVE-2026-68347)
| Summary: | CVE-2026-68347 kernel: iommu/amd: Fix IRQ unsafe locking in gdom allocation | ||
|---|---|---|---|
| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security <prodsec-ir-bot> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, 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's AMD IOMMU (Input/Output Memory Management Unit) driver. This vulnerability is caused by an unsafe lock order during the allocation of graphics domains (gdom) and within the IOMMU_DESTROY free path. This issue could lead to a system crash or a denial of service (DoS) due to a kernel concurrency problem.
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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: iommu/amd: Fix IRQ unsafe locking in gdom allocation Lockdep complains: [ 259.410489] ===================================================== [ 259.417287] WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected [ 259.424667] 7.0.0-g51db1d8d2113 #54 Not tainted [ 259.429718] ----------------------------------------------------- [ 259.436516] qemu-system-x86/10143 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: [ 259.444670] ff3b2b1c60305170 (&xa->xa_lock#25){+.+.}-{3:3}, at: __domain_flush_pages+0x17c/0x4b0 [ 259.454485] and this task is already holding: [ 259.460991] ff3b2b1c98504cc0 (&domain->lock){-.-.}-{3:3}, at: amd_iommu_iotlb_sync+0x25/0x60 [ 259.470408] which would create a new lock dependency: [ 259.476041] (&domain->lock){-.-.}-{3:3} -> (&xa->xa_lock#25){+.+.}-{3:3} [ 259.483615] but this new dependency connects a HARDIRQ-irq-safe lock: [ 259.492447] (&domain->lock){-.-.}-{3:3} [ 259.492449] ... which became HARDIRQ-irq-safe at: [ 259.503705] lock_acquire+0xb6/0x2e0 [ 259.507790] _raw_spin_lock_irqsave+0x3e/0x60 [ 259.512748] amd_iommu_flush_iotlb_all+0x20/0x50 [ 259.517996] iommu_dma_free_iova.isra.0+0x1b8/0x1e0 [ 259.523534] __iommu_dma_unmap+0xc2/0x140 [ 259.528100] iommu_dma_unmap_phys+0x55/0xc0 [ 259.532863] dma_unmap_phys+0x274/0x2e0 [ 259.537238] dma_unmap_page_attrs+0x17/0x30 [ 259.542000] nvme_unmap_data+0x13e/0x280 [ 259.546473] nvme_pci_complete_batch+0x45/0x70 [ 259.551524] nvme_irq+0x83/0x90 [ 259.555123] __handle_irq_event_percpu+0x92/0x360 [ 259.560466] handle_irq_event+0x39/0x80 [ 259.564841] handle_edge_irq+0xb2/0x1a0 [ 259.569214] __common_interrupt+0x4e/0x130 [ 259.573882] common_interrupt+0x88/0xa0 [ 259.578256] asm_common_interrupt+0x27/0x40 [ 259.583019] cpuidle_enter_state+0x119/0x5d0 [ 259.587877] cpuidle_enter+0x2e/0x50 [ 259.591962] do_idle+0x153/0x2c0 [ 259.595657] cpu_startup_entry+0x29/0x30 [ 259.600128] start_secondary+0x118/0x150 [ 259.604601] common_startup_64+0x13e/0x141 [ 259.609266] to a HARDIRQ-irq-unsafe lock: [ 259.615384] (&xa->xa_lock#25){+.+.}-{3:3} [ 259.615386] ... which became HARDIRQ-irq-unsafe at: [ 259.627039] ... [ 259.627039] lock_acquire+0xb6/0x2e0 [ 259.633071] _raw_spin_lock+0x2f/0x50 [ 259.637250] amd_iommu_alloc_domain_nested+0x140/0x3c0 [ 259.643078] iommufd_hwpt_alloc+0x272/0x800 [iommufd] [ 259.648813] iommufd_fops_ioctl+0x14e/0x200 [iommufd] [ 259.654547] __x64_sys_ioctl+0x9d/0xf0 ... Since amd_iommu_domain_flush_pages() necessarily holds domain->lock to do the flush, switch the allocation side in gdom_info_load_or_alloc_locked() to HARDIRQ-safe allocation. The IOMMU_DESTROY->free path has the same issue, so switch that path to HARDIRQ-safe locking as well.