Bug 2309789 (CVE-2024-44958)

Summary: CVE-2024-44958 kernel: sched/smt: Fix unbalance sched_smt_present dec/inc
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, pauld, rgatica, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---Flags: pauld: needinfo? (rgatica)
Hardware: All   
OS: Linux   
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Bug Depends On: 2309835    
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Description OSIDB Bzimport 2024-09-04 19:20:54 UTC 
In the Linux kernel, the following vulnerability has been resolved:

sched/smt: Fix unbalance sched_smt_present dec/inc

I got the following warn report while doing stress test:

jump label: negative count!
WARNING: CPU: 3 PID: 38 at kernel/jump_label.c:263 static_key_slow_try_dec+0x9d/0xb0
Call Trace:
 <TASK>
 __static_key_slow_dec_cpuslocked+0x16/0x70
 sched_cpu_deactivate+0x26e/0x2a0
 cpuhp_invoke_callback+0x3ad/0x10d0
 cpuhp_thread_fun+0x3f5/0x680
 smpboot_thread_fn+0x56d/0x8d0
 kthread+0x309/0x400
 ret_from_fork+0x41/0x70
 ret_from_fork_asm+0x1b/0x30
 </TASK>

Because when cpuset_cpu_inactive() fails in sched_cpu_deactivate(),
the cpu offline failed, but sched_smt_present is decremented before
calling sched_cpu_deactivate(), it leads to unbalanced dec/inc, so
fix it by incrementing sched_smt_present in the error path.
Comment 1 Robb Gatica 2024-09-04 20:20:20 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024090413-CVE-2024-44958-80e9@gregkh/T
Comment 4 errata-xmlrpc 2025-05-13 08:27:57 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2025:6966 https://access.redhat.com/errata/RHSA-2025:6966