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Description

In the Linux kernel, the following vulnerability has been resolved: PCI: Fix link speed calculation on retrain failure When pcie_failed_link_retrain() fails to retrain, it tries to revert to the previous link speed. However it calculates that speed from the Link Control 2 register without masking out non-speed bits first. PCIE_LNKCTL2_TLS2SPEED() converts such incorrect values to PCI_SPEED_UNKNOWN (0xff), which in turn causes a WARN splat in pcie_set_target_speed(): pci 0000:00:01.1: [1022:14ed] type 01 class 0x060400 PCIe Root Port pci 0000:00:01.1: broken device, retraining non-functional downstream link at 2.5GT/s pci 0000:00:01.1: retraining failed WARNING: CPU: 1 PID: 1 at drivers/pci/pcie/bwctrl.c:168 pcie_set_target_speed RDX: 0000000000000001 RSI: 00000000000000ff RDI: ffff9acd82efa000 pcie_failed_link_retrain pci_device_add pci_scan_single_device Mask out the non-speed bits in PCIE_LNKCTL2_TLS2SPEED() and PCIE_LNKCAP_SLS2SPEED() so they don't incorrectly return PCI_SPEED_UNKNOWN. [bhelgaas: commit log, add details from https://lore.kernel.org/r/1c92ef6bcb314ee6977839b46b393282e4f52e74.1750684771.git.lukas@wunner.de]

PUBLISHED Reserved 2025-04-16 | Published 2025-09-11 | Updated 2025-09-29 | Assigner Linux

Product status

Default status
unaffected

de9a6c8d5dbfedb5eb3722c822da0490f6a59a45 (git) before 16557320f378262b5c605b15edebd3642406992a
affected

de9a6c8d5dbfedb5eb3722c822da0490f6a59a45 (git) before 9989e0ca7462c62f93dbc62f684448aa2efb9226
affected

Default status
affected

6.13
affected

Any version before 6.13
unaffected

6.16.4 (semver)
unaffected

6.17 (original_commit_for_fix)
unaffected

References

git.kernel.org/...c/16557320f378262b5c605b15edebd3642406992a

git.kernel.org/...c/9989e0ca7462c62f93dbc62f684448aa2efb9226

cve.org (CVE-2025-39784)

nvd.nist.gov (CVE-2025-39784)

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