DescriptionIn the Linux kernel, the following vulnerability has been resolved: platform/x86: p2sb: Allow p2sb_bar() calls during PCI device probe p2sb_bar() unhides P2SB device to get resources from the device. It guards the operation by locking pci_rescan_remove_lock so that parallel rescans do not find the P2SB device. However, this lock causes deadlock when PCI bus rescan is triggered by /sys/bus/pci/rescan. The rescan locks pci_rescan_remove_lock and probes PCI devices. When PCI devices call p2sb_bar() during probe, it locks pci_rescan_remove_lock again. Hence the deadlock. To avoid the deadlock, do not lock pci_rescan_remove_lock in p2sb_bar(). Instead, do the lock at fs_initcall. Introduce p2sb_cache_resources() for fs_initcall which gets and caches the P2SB resources. At p2sb_bar(), refer the cache and return to the caller. Before operating the device at P2SB DEVFN for resource cache, check that its device class is PCI_CLASS_MEMORY_OTHER 0x0580 that PCH specifications define. This avoids unexpected operation to other devices at the same DEVFN. Tested-by Klara Modin <>
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)buster4.19.249-2fixed
buster (security)4.19.304-1fixed
bullseye (security)5.10.205-2fixed
bookworm (security)6.1.85-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebuster(not affected)
linuxsourcebullseye(not affected)


[bullseye] - linux <not-affected> (Vulnerable code not present)
[buster] - linux <not-affected> (Vulnerable code not present) (6.8-rc2)

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