GHSA-9V6F-6HX3-8XXJ
Vulnerability from github – Published: 2026-09-09 18:32 – Updated: 2026-09-09 18:32In the Linux kernel, the following vulnerability has been resolved:
PCI: host-generic: Fix NULL pointer dereference on 32-bit CAM systems
On 32-bit systems the config space is too large to ioremap in one go, so pci_ecam_create() maps each bus segment separately and relies on the ->add_bus callback (pci_ecam_add_bus) to populate the per-bus mapping in cfg->winp[]. pci_ecam_map_bus() then uses that mapping as the base for every config access.
The generic ECAM ops (pci_generic_ecam_ops) already provide the ->add_bus and ->remove_bus callbacks, but the CAM (legacy) ops in pci-host-generic.c do not. As a result, on a 32-bit host using "pci-host-cam-generic" the per-bus mapping is never set up and the first config read dereferences a NULL base, crashing during bus enumeration:
Unable to handle kernel NULL pointer dereference at virtual address 00000800 Oops [#1] CPU: 0 PID: 1 Comm: swapper Not tainted 6.9.7+ #43 Hardware name: Digilent Nexys-Video-A7 RV32 (DT) epc : pci_generic_config_read+0x40/0xb0 ra : pci_generic_config_read+0x2c/0xb0 [] pci_generic_config_read+0x40/0xb0 [] pci_bus_read_config_dword+0x50/0xb0 [] pci_bus_generic_read_dev_vendor_id+0x3c/0x1ec [] pci_scan_single_device+0xa4/0x11c [] pci_scan_slot+0x9c/0x23c [] pci_scan_child_bus_extend+0x58/0x2f4 [] pci_scan_root_bus_bridge+0x64/0xe8 [] pci_host_probe+0x20/0xc8 [] pci_host_common_probe+0x144/0x1e4
Fix this by giving the CAM ops the same ->add_bus/->remove_bus callbacks. Since pci_ecam_add_bus() and pci_ecam_remove_bus() are static to ecam.c, move the CAM ops definition there as pci_generic_cam_ops (mirroring pci_generic_ecam_ops) and export it for pci-host-generic.c to reference.
[mani: removed timestamp from log]
{
"affected": [],
"aliases": [
"CVE-2026-80917"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-09T17:17:46Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nPCI: host-generic: Fix NULL pointer dereference on 32-bit CAM systems\n\nOn 32-bit systems the config space is too large to ioremap in one go, so\npci_ecam_create() maps each bus segment separately and relies on the\n-\u003eadd_bus callback (pci_ecam_add_bus) to populate the per-bus mapping in\ncfg-\u003ewinp[]. pci_ecam_map_bus() then uses that mapping as the base for\nevery config access.\n\nThe generic ECAM ops (pci_generic_ecam_ops) already provide the -\u003eadd_bus\nand -\u003eremove_bus callbacks, but the CAM (legacy) ops in pci-host-generic.c\ndo not. As a result, on a 32-bit host using \"pci-host-cam-generic\" the\nper-bus mapping is never set up and the first config read dereferences a\nNULL base, crashing during bus enumeration:\n\n Unable to handle kernel NULL pointer dereference at virtual address 00000800\n Oops [#1]\n CPU: 0 PID: 1 Comm: swapper Not tainted 6.9.7+ #43\n Hardware name: Digilent Nexys-Video-A7 RV32 (DT)\n epc : pci_generic_config_read+0x40/0xb0\n ra : pci_generic_config_read+0x2c/0xb0\n [\u003cc038db9c\u003e] pci_generic_config_read+0x40/0xb0\n [\u003cc038da04\u003e] pci_bus_read_config_dword+0x50/0xb0\n [\u003cc0391e94\u003e] pci_bus_generic_read_dev_vendor_id+0x3c/0x1ec\n [\u003cc039245c\u003e] pci_scan_single_device+0xa4/0x11c\n [\u003cc0392570\u003e] pci_scan_slot+0x9c/0x23c\n [\u003cc039388c\u003e] pci_scan_child_bus_extend+0x58/0x2f4\n [\u003cc0393db0\u003e] pci_scan_root_bus_bridge+0x64/0xe8\n [\u003cc0393e54\u003e] pci_host_probe+0x20/0xc8\n [\u003cc03bc6f4\u003e] pci_host_common_probe+0x144/0x1e4\n\nFix this by giving the CAM ops the same -\u003eadd_bus/-\u003eremove_bus callbacks.\nSince pci_ecam_add_bus() and pci_ecam_remove_bus() are static to ecam.c,\nmove the CAM ops definition there as pci_generic_cam_ops (mirroring\npci_generic_ecam_ops) and export it for pci-host-generic.c to reference.\n\n[mani: removed timestamp from log]",
"id": "GHSA-9v6f-6hx3-8xxj",
"modified": "2026-09-09T18:32:04Z",
"published": "2026-09-09T18:32:04Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80917"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/008cb88edb41f3c7c8e0ed763ff9f26719830984"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0916948026f623844acd08888f7cbedbf1c48d6b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0c55707bd5d0d7670704cfd0dda933809b052f67"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5e52eb0290f66ba0732956dcb1e365b5ca3c5108"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/74456843f18ba7f3045974d7e8b88ab993152b8c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8d08713ec83a18526d1ed1fd5f0d2b901d103a10"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a199293f3038db8d31d47aa60f1e18272cd82354"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/baf9b0383ff770fdff123d3a832f3a99641d96dd"
}
],
"schema_version": "1.4.0",
"severity": []
}
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