Race Condition Affecting kernel-rt-debug-kvm package, versions <0:4.18.0-553.rt7.342.el8_10
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Test your applications- Snyk ID SNYK-CENTOS8-KERNELRTDEBUGKVM-6527834
- published 3 Apr 2024
- disclosed 2 Apr 2024
Introduced: 2 Apr 2024
CVE-2024-26671 Open this link in a new tabHow to fix?
Upgrade Centos:8 kernel-rt-debug-kvm to version 0:4.18.0-553.rt7.342.el8_10 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug-kvm package and not the kernel-rt-debug-kvm package as distributed by Centos.
See How to fix? for Centos:8 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
blk-mq: fix IO hang from sbitmap wakeup race
In blk_mq_mark_tag_wait(), __add_wait_queue() may be re-ordered with the following blk_mq_get_driver_tag() in case of getting driver tag failure.
Then in __sbitmap_queue_wake_up(), waitqueue_active() may not observe the added waiter in blk_mq_mark_tag_wait() and wake up nothing, meantime blk_mq_mark_tag_wait() can't get driver tag successfully.
This issue can be reproduced by running the following test in loop, and fio hang can be observed in < 30min when running it on my test VM in laptop.
modprobe -r scsi_debug
modprobe scsi_debug delay=0 dev_size_mb=4096 max_queue=1 host_max_queue=1 submit_queues=4
dev=`ls -d /sys/bus/pseudo/drivers/scsi_debug/adapter*/host*/target*/*/block/* | head -1 | xargs basename`
fio --filename=/dev/"$dev" --direct=1 --rw=randrw --bs=4k --iodepth=1 \
--runtime=100 --numjobs=40 --time_based --name=test \
--ioengine=libaio
Fix the issue by adding one explicit barrier in blk_mq_mark_tag_wait(), which is just fine in case of running out of tag.
References
- https://access.redhat.com/security/cve/CVE-2024-26671
- https://git.kernel.org/stable/c/1d9c777d3e70bdc57dddf7a14a80059d65919e56
- https://git.kernel.org/stable/c/5266caaf5660529e3da53004b8b7174cab6374ed
- https://git.kernel.org/stable/c/6d8b01624a2540336a32be91f25187a433af53a0
- https://git.kernel.org/stable/c/7610ba1319253225a9ba8a9d28d472fc883b4e2f
- https://git.kernel.org/stable/c/89e0e66682e1538aeeaa3109503473663cd24c8b
- https://git.kernel.org/stable/c/9525b38180e2753f0daa1a522b7767a2aa969676
- https://git.kernel.org/stable/c/ecd7744a1446eb02ccc63e493e2eb6ede4ef1e10
- https://git.kernel.org/stable/c/f1bc0d8163f8ee84a8d5affdf624cfad657df1d2
- https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html
- https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html