IB/hfi1: Fix the PIO_CRED credit-return mmap

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-98216
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-06 09:18:08 UTC
Updated2026-10-07 07:17:04 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: IB/hfi1: Fix the PIO_CRED credit-return mmap hfi1_file_mmap()'s PIO_CRED case must hand user space the single credit-return page that holds this context's entry. That page is the second or third page of the per-node credit-return allocation once the hardware send context index reaches 64 or 128, so the failure below is intermittent: when the entry lands on the first page the offset is zero and everything works. Two things are wrong. First, cr_page_offset is a byte offset but .va is a struct credit_return *, so adding it is pointer arithmetic and scales the offset by sizeof(struct credit_return) == 64. memvirt then lands 256 KiB or 512 KiB past a 10240-byte allocation. With an IOMMU translating, that address is inside the vmalloc range but in no vm_area, so dma_mmap_coherent() -> iommu_dma_mmap() finds no pages, vmalloc_to_pfn() returns page_to_pfn(NULL), and remap_pfn_range() installs a frame above MAXPHYADDR. The first user read then takes: psm2_ep_open_pr: Corrupted page table at address 7a14d007e000 PGD 800000013886a067 P4D 800000013886a067 PUD 13886b067 PMD 13886c067 PTE 800049168e911235 Oops: Bad pagetable: 000d [#1] SMP PTI Second, and still wrong once the arithmetic is corrected, dma_mmap_coherent() describes a whole coherent buffer and selects the page within it with vma->vm_pgoff. Offsetting cpu_addr has no effect: for a vmap'd allocation iommu_dma_mmap() uses cpu_addr only to locate the vm_area and then maps pages[vm_pgoff], which hfi1_file_mmap() has just set to 0. User space therefore always receives the first credit-return page, every credit read is for the wrong context, and send PIO stalls forever. Use the DMA API as intended: pass the base of the allocation with its full length and select the page with vm_pgoff. A separate length is needed because memlen must keep describing the VMA for the existing size check. The dma-direct path stays correct as well, since dma_direct_mmap() adds the same vm_pgoff to the base pfn. Tested on a Dell T7610 (Xeon E5-2650 v2, Intel IOMMU in DMA-FQ mode) against a Threadripper PRO 3995WX peer, both Omni-Path 100. Before this change psm2_ep_open() Oopses the kernel; with only the arithmetic corrected psm2_ep_open() succeeds but any transfer that uses send PIO hangs, PSM2_SDMA=2 (send PIO disabled) completing normally while PSM2_SDMA=0 (send PIO only) hangs every time. With this change send PIO, send DMA and the default mixed mode all work.

Risk And Classification

Primary CVSS: v3.1 7.1 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

EPSS: 0.001750000 probability, percentile 0.063860000 (date 2026-10-06)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
3.1CNADECLARED7.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 1ec82317a1daac78c04b0c15af89018ccf9fa2b7 535530bb2ea5254e1e9f55280143d262dd065204 git Not specified
CNA Linux Linux affected 1ec82317a1daac78c04b0c15af89018ccf9fa2b7 dcebe0b0bb080a25fe08011fd6b6e741f7912f01 git Not specified
CNA Linux Linux affected 1ec82317a1daac78c04b0c15af89018ccf9fa2b7 180752deb7270ad37394ab6ef7cf4978fad040b3 git Not specified
CNA Linux Linux affected 1ec82317a1daac78c04b0c15af89018ccf9fa2b7 bafeac9ce5d1ce5256bcf7e5702e831e9aaf419b git Not specified
CNA Linux Linux affected 1ec82317a1daac78c04b0c15af89018ccf9fa2b7 62f0f34fbd2b2d5653d33d3b9d42fdcabb1c0101 git Not specified
CNA Linux Linux affected 6.3 Not specified
CNA Linux Linux unaffected 6.3 semver Not specified
CNA Linux Linux unaffected 6.6.158 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.112 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.54 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.8 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc4 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/535530bb2ea5254e1e9f55280143d262dd065204 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/62f0f34fbd2b2d5653d33d3b9d42fdcabb1c0101 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bafeac9ce5d1ce5256bcf7e5702e831e9aaf419b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/dcebe0b0bb080a25fe08011fd6b6e741f7912f01 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/180752deb7270ad37394ab6ef7cf4978fad040b3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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