Description

In the Linux kernel, the following vulnerability has been resolved:

PCI/ASPM: Fix deadlock when enabling ASPM

A last minute revert in 6.7-final introduced a potential deadlock when
enabling ASPM during probe of Qualcomm PCIe controllers as reported by
lockdep:

============================================
WARNING: possible recursive locking detected
6.7.0 #40 Not tainted
--------------------------------------------
kworker/u16:5/90 is trying to acquire lock:
ffffacfa78ced000 (pci_bus_sem){++++}-{3:3}, at: pcie_aspm_pm_state_change+0x58/0xdc

but task is already holding lock:
ffffacfa78ced000 (pci_bus_sem){++++}-{3:3}, at: pci_walk_bus+0x34/0xbc

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(pci_bus_sem);
lock(pci_bus_sem);

*** DEADLOCK ***

Call trace:
print_deadlock_bug+0x25c/0x348
__lock_acquire+0x10a4/0x2064
lock_acquire+0x1e8/0x318
down_read+0x60/0x184
pcie_aspm_pm_state_change+0x58/0xdc
pci_set_full_power_state+0xa8/0x114
pci_set_power_state+0xc4/0x120
qcom_pcie_enable_aspm+0x1c/0x3c [pcie_qcom]
pci_walk_bus+0x64/0xbc
qcom_pcie_host_post_init_2_7_0+0x28/0x34 [pcie_qcom]

The deadlock can easily be reproduced on machines like the Lenovo ThinkPad
X13s by adding a delay to increase the race window during asynchronous
probe where another thread can take a write lock.

Add a new pci_set_power_state_locked() a...

Classification

CVE ID: CVE-2024-26605

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 5.08% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/0f7908a016c092cfdaa16d785fa5099d867bc1a3
https://git.kernel.org/stable/c/b0f4478838be1f1d330061201898fef65bf8fd7c
https://git.kernel.org/stable/c/ef90508574d7af48420bdc5f7b9a4f1cdd26bc70
https://git.kernel.org/stable/c/1e560864159d002b453da42bd2c13a1805515a20

Timeline