UNKNOWN NVD
CVE-2026-98262
In the Linux kernel, the following vulnerability has been resolved: ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY A user reported that commit
In the Linux kernel, the following vulnerability has been resolved:
ata: libahci: clear PxCLBU and PxFBU for AHCI_HFLAG_32BIT_ONLY
A user reported that commit 105c42566a55 ("ata: ahci: force 32-bit DMA for
JMicron JMB582/JMB585") made the JMicron JMB585 unusable on his board.
The failure is seen as soon as the ahci driver is probed, and booting with
iommu=off does not solve the problem.
Looking at the AHCI specification, PxCLBU and PxFBU are both read only '0'
for HBAs that do not support 64-bit addressing.
For HBAs that do support 64-bit addressing, the registers are read write,
with a reset value that is Implementation Specific.
When using the AHCI_HFLAG_32BIT_ONLY flag, the HBA does support 64-bit
addressing, and a 32-bit DMA mask is set by simply clearing HOST_CAP_64.
Thus, in this case, we need to explicitly clear the registers to 0.
References
- https://git.kernel.org/stable/c/0191c9ff23ef1678dbfb5ad253a2dee92feb5d71
- https://git.kernel.org/stable/c/4719424bb7cb9f20b73986bcb72dd528f0e5c6eb
- https://git.kernel.org/stable/c/7912ad8fb5233bb8cfe21d50df639c7f4854ff9d
- https://git.kernel.org/stable/c/82e47533221d4746947b74d2e79a478c36c6433a
- https://git.kernel.org/stable/c/8f510f68208a1f673d7c7234a687be4671490e9c
This unknown severity vulnerability was published on 2026-10-06 via NVD.
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