Linux Kernel: Vulnerability in Memory Management Affects Multiple Implementations

CVE-2025-39843

What is CVE-2025-39843?

A vulnerability in the Linux kernel's memory management subsystem can lead to lock recursion issues during the execution of the set_track_prepare() function. This function is invoked by hrtimer_start_range_ns while holding a specific lock related to per_cpu(hrtimer_bases)[n]. If the CONFIG_DEBUG_OBJECTS_TIMERS option is enabled, it may inadvertently wake up kswapd, attempting to hold the same lock, which can cause a deadlock situation. To mitigate this risk, allocation flags that exclude __GFP_KSWAPD_RECLAIM are passed during the debug_objects_fill_pool() operation to prevent kswapd from being woken up in this context. This vulnerability poses a considerable risk to system stability and requires immediate attention in affected configurations.

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