CVE-2024-35929 Affecting kernel-rt-trace-kvm package, versions *
Threat Intelligence
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Test your applications- Snyk IDSNYK-CENTOS7-KERNELRTTRACEKVM-6926720
- published20 May 2024
- disclosed19 May 2024
Introduced: 19 May 2024
CVE-2024-35929 (opens in a new tab)How to fix?
There is no fixed version for Centos:7 kernel-rt-trace-kvm.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-rt-trace-kvm package and not the kernel-rt-trace-kvm package as distributed by Centos.
See How to fix? for Centos:7 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
rcu/nocb: Fix WARN_ON_ONCE() in the rcu_nocb_bypass_lock()
For the kernels built with CONFIG_RCU_NOCB_CPU_DEFAULT_ALL=y and CONFIG_RCU_LAZY=y, the following scenarios will trigger WARN_ON_ONCE() in the rcu_nocb_bypass_lock() and rcu_nocb_wait_contended() functions:
CPU2 CPU11
kthread rcu_nocb_cb_kthread ksys_write rcu_do_batch vfs_write rcu_torture_timer_cb proc_sys_write __kmem_cache_free proc_sys_call_handler kmemleak_free drop_caches_sysctl_handler delete_object_full drop_slab __delete_object shrink_slab put_object lazy_rcu_shrink_scan call_rcu rcu_nocb_flush_bypass _call_rcu_commn rcu_nocb_bypass_lock raw_spin_trylock(&rdp->nocb_bypass_lock) fail atomic_inc(&rdp->nocb_lock_contended); rcu_nocb_wait_contended WARN_ON_ONCE(smp_processor_id() != rdp->cpu); WARN_ON_ONCE(atomic_read(&rdp->nocb_lock_contended)) | | _ _ _ _ _ _ _ _ same rdp and rdp->cpu != 11 _ _ _ _ _ _ _ _ __|
Reproduce this bug with "echo 3 > /proc/sys/vm/drop_caches".
This commit therefore uses rcu_nocb_try_flush_bypass() instead of rcu_nocb_flush_bypass() in lazy_rcu_shrink_scan(). If the nocb_bypass queue is being flushed, then rcu_nocb_try_flush_bypass will return directly.