Description

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Free exactly when function 0 is removed -- before the parent link is
obsolete, but after all subordinate links are gone.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]

Classification

CVE ID: CVE-2024-58093

Affected Products

Vendor: Linux

Product: Linux, Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.02% (probability of being exploited)

EPSS Percentile: 3.26% (scored less or equal to compared to others)

EPSS Date: 2025-04-20 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2024-58093
https://git.kernel.org/stable/c/cbf937dcadfd571a434f8074d057b32cd14fbea5

Timeline