Bug 2275571 (CVE-2024-26841)

Summary: CVE-2024-26841 kernel: LoongArch: Update cpu_sibling_map when disabling nonboot CPUs
Product: [Other] Security Response Reporter: Robb Gatica <rgatica>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: acaringi, allarkin, aquini, bhu, chwhite, cye, cyin, dbohanno, debarbos, dfreiber, drow, dvlasenk, esandeen, ezulian, hkrzesin, jarod, jburrell, jdenham, jfaracco, jlelli, joe.lawrence, jshortt, jstancek, jwyatt, kcarcia, ldoskova, lgoncalv, lzampier, mleitner, mmilgram, mstowell, nmurray, ptalbert, rparrazo, rrobaina, rvrbovsk, rysulliv, scweaver, sidakwo, sukulkar, tglozar, tyberry, vkumar, wcosta, williams, wmealing, ycote, ykopkova, zhijwang
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: kernel 6.6.19, kernel 6.7.7, kernel 6.8 Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in the Linux kernel. This vulnerability specifically affects LoongArch processors. The issue is related to the CPU sibling map, which is not correctly updated when non-boot CPUs are disabled. This issue could lead to errors on Symmetric Multi-Threading (SMT) systems, such as generating warnings like "jump label: negative count!" when disabling certain CPUs. The vulnerability could potentially cause system instability or kernel crashes, especially in environments that rely on SMT. The issue was resolved by defining and calling the function clear_cpu_sibling_map() to properly manage the CPU sibling map, preventing the errors. While this vulnerability doesn't appear to be remotely exploitable, it could still impact local users under specific conditions​.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2275572    
Bug Blocks: 2275560    

Description Robb Gatica 2024-04-17 16:00:59 UTC 
In the Linux kernel, the following vulnerability has been resolved:

LoongArch: Update cpu_sibling_map when disabling nonboot CPUs

The Linux kernel CVE team has assigned CVE-2024-26841 to this issue.

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024041716-CVE-2024-26841-6433@gregkh/T
Comment 1 Robb Gatica 2024-04-17 16:01:51 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2275572]
Comment 5 Rohit Keshri 2024-04-25 11:28:03 UTC 
Does not seems to have a security impact.