{"id":"CVE-2025-39784","summary":"PCI: Fix link speed calculation on retrain failure","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nPCI: Fix link speed calculation on retrain failure\n\nWhen pcie_failed_link_retrain() fails to retrain, it tries to revert to the\nprevious link speed.  However it calculates that speed from the Link\nControl 2 register without masking out non-speed bits first.\n\nPCIE_LNKCTL2_TLS2SPEED() converts such incorrect values to\nPCI_SPEED_UNKNOWN (0xff), which in turn causes a WARN splat in\npcie_set_target_speed():\n\n  pci 0000:00:01.1: [1022:14ed] type 01 class 0x060400 PCIe Root Port\n  pci 0000:00:01.1: broken device, retraining non-functional downstream link at 2.5GT/s\n  pci 0000:00:01.1: retraining failed\n  WARNING: CPU: 1 PID: 1 at drivers/pci/pcie/bwctrl.c:168 pcie_set_target_speed\n  RDX: 0000000000000001 RSI: 00000000000000ff RDI: ffff9acd82efa000\n  pcie_failed_link_retrain\n  pci_device_add\n  pci_scan_single_device\n\nMask out the non-speed bits in PCIE_LNKCTL2_TLS2SPEED() and\nPCIE_LNKCAP_SLS2SPEED() so they don't incorrectly return PCI_SPEED_UNKNOWN.\n\n[bhelgaas: commit log, add details from https://lore.kernel.org/r/1c92ef6bcb314ee6977839b46b393282e4f52e74.1750684771.git.lukas@wunner.de]","modified":"2026-04-02T12:48:09.682554Z","published":"2025-09-11T16:56:34.097Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39784.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/16557320f378262b5c605b15edebd3642406992a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9989e0ca7462c62f93dbc62f684448aa2efb9226"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39784.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-39784"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"de9a6c8d5dbfedb5eb3722c822da0490f6a59a45"},{"fixed":"16557320f378262b5c605b15edebd3642406992a"},{"fixed":"9989e0ca7462c62f93dbc62f684448aa2efb9226"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39784.json"}}],"schema_version":"1.7.5"}