Ubuntu: (CVE-2021-47617): linux vulnerability

Ubuntu: (CVE-2021-47617): linux vulnerability

Severity

5

CVSS

(AV:L/AC:L/Au:S/C:N/I:N/A:C)

Published

06/20/2024

Created

11/21/2024

Added

11/19/2024

Modified

02/11/2025

Description

In the Linux kernel, the following vulnerability has been resolved: PCI: pciehp: Fix infinite loop in IRQ handler upon power fault The Power Fault Detected bit in the Slot Status register differs from all other hotplug events in that it is sticky:It can only be cleared after turning off slot power.Per PCIe r5.0, sec. 6.7.1.8: If a power controller detects a main power fault on the hot-plug slot, it must automatically set its internal main power fault latch [...]. The main power fault latch is cleared when software turns off power to the hot-plug slot. The stickiness used to cause interrupt storms and infinite loops which were fixed in 2009 by commits 5651c48cfafe ("PCI pciehp: fix power fault interrupt storm problem") and 99f0169c17f3 ("PCI: pciehp: enable software notification on empty slots"). Unfortunately in 2020 the infinite loop issue was inadvertently reintroduced by commit 8edf5332c393 ("PCI: pciehp: Fix MSI interrupt race"):The hardirq handler pciehp_isr() clears the PFD bit until pciehp's power_fault_detected flag is set.That happens in the IRQ thread pciehp_ist(), which never learns of the event because the hardirq handler is stuck in an infinite loop.Fix by setting the power_fault_detected flag already in the hardirq handler.

Solution(s)

• ubuntu-upgrade-linux
• ubuntu-upgrade-linux-aws
• ubuntu-upgrade-linux-aws-5-4
• ubuntu-upgrade-linux-aws-fips
• ubuntu-upgrade-linux-azure
• ubuntu-upgrade-linux-azure-5-4
• ubuntu-upgrade-linux-azure-fips
• ubuntu-upgrade-linux-bluefield
• ubuntu-upgrade-linux-fips
• ubuntu-upgrade-linux-gcp
• ubuntu-upgrade-linux-gcp-5-4
• ubuntu-upgrade-linux-gcp-fips
• ubuntu-upgrade-linux-gkeop
• ubuntu-upgrade-linux-hwe-5-4
• ubuntu-upgrade-linux-ibm
• ubuntu-upgrade-linux-ibm-5-4
• ubuntu-upgrade-linux-intel-iotg-5-15
• ubuntu-upgrade-linux-iot
• ubuntu-upgrade-linux-kvm
• ubuntu-upgrade-linux-oracle
• ubuntu-upgrade-linux-oracle-5-4
• ubuntu-upgrade-linux-raspi
• ubuntu-upgrade-linux-raspi-5-4

References

• https://attackerkb.com/topics/cve-2021-47617
• CVE - 2021-47617
• https://git.kernel.org/linus/23584c1ed3e15a6f4bfab8dc5a88d94ab929ee12
• https://git.kernel.org/stable/c/1db58c6584a72102e98af2e600ea184ddaf2b8af
• https://git.kernel.org/stable/c/23584c1ed3e15a6f4bfab8dc5a88d94ab929ee12
• https://git.kernel.org/stable/c/3b4c966fb156ff3e70b2526d964952ff7c1574d9
• https://git.kernel.org/stable/c/464da38ba827f670deac6500a1de9a4f0f44c41d
• https://git.kernel.org/stable/c/6d6f1f0dac3e3441ecdb1103d4efb11b9ed24dd5
• https://git.kernel.org/stable/c/ff27f7d0333cff89ec85c419f431aca1b38fb16a
• https://www.cve.org/CVERecord?id=CVE-2021-47617

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