Linux · Linux Kernel · CVE-2021-47617
Name of the Vulnerable Software and Affected Versions:
Linux kernel (affected versions not specified)
Description:
The issue is related to an infinite loop in the IRQ handler upon power fault in the Linux kernel's PCI: pciehp component. The Power Fault Detected bit in the Slot Status register is sticky and can only be cleared after turning off slot power. This stickiness used to cause interrupt storms and infinite loops, which were fixed in 2009 but inadvertently reintroduced in 2020 by a commit. The hardirq handler pciehp isr() clears the PFD bit until pciehp's power fault detected flag is set, but this happens in the IRQ thread pciehp ist(), which never learns of the event because the hardirq handler is stuck in an infinite loop. The fix involves setting the power fault detected flag already in the hardirq handler.
Recommendations:
At the moment, there is no information about a newer version that contains a fix for this vulnerability.