Bug 2360287 (CVE-2024-58093)

Summary: CVE-2024-58093 kernel: PCI/ASPM: Fix link state exit during switch upstream function removal
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-04-16 15:06:29 UTC
In the Linux kernel, the following vulnerability has been resolved:

PCI/ASPM: Fix link state exit during switch upstream function removal

Before 456d8aa37d0f ("PCI/ASPM: Disable ASPM on MFD function removal to
avoid use-after-free"), we would free the ASPM link only after the last
function on the bus pertaining to the given link was removed.

That was too late. If function 0 is removed before sibling function,
link->downstream would point to free'd memory after.

After above change, we freed the ASPM parent link state upon any function
removal on the bus pertaining to a given link.

That is too early. If the link is to a PCIe switch with MFD on the upstream
port, then removing functions other than 0 first would free a link which
still remains parent_link to the remaining downstream ports.

The resulting GPFs are especially frequent during hot-unplug, because
pciehp removes devices on the link bus in reverse order.

On that switch, function 0 is the virtual P2P bridge to the internal bus.
Free exactly when function 0 is removed -- before the parent link is
obsolete, but after all subordinate links are gone.

[kwilczynski: commit log]

Comment 1 Avinash Hanwate 2025-04-17 06:40:06 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025041652-CVE-2024-58093-2638@gregkh/T