CVE-2025-68253 in Linux
Summary
by MITRE • 12/16/2025
In the Linux kernel, the following vulnerability has been resolved:
mm: don't spin in add_stack_record when gfp flags don't allow
syzbot was able to find the following path: add_stack_record_to_list mm/page_owner.c:182 [inline]
inc_stack_record_count mm/page_owner.c:214 [inline]
__set_page_owner+0x2c3/0x4a0 mm/page_owner.c:333 set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline]
get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858 alloc_pages_nolock_noprof+0x94/0x120 mm/page_alloc.c:7554
Don't spin in add_stack_record_to_list() when it is called from *_nolock() context.
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Analysis
by VulDB Data Team • 02/22/2026
The vulnerability identified as CVE-2025-68253 represents a critical concurrency issue within the Linux kernel's memory management subsystem, specifically affecting the page owner tracking mechanism. This flaw manifests in the mm/page_owner.c file where the add_stack_record_to_list function enters an infinite spin loop when invoked from certain lock-free contexts. The issue was discovered through systematic fuzzing by syzbot, which systematically identified execution paths leading to this problematic behavior. The call stack reveals the vulnerability originates from the page owner tracking system when pages are allocated through the page allocator, specifically during the post allocation hook execution. The root cause stems from the function's inability to properly handle GFP (Get Free Page) flags that indicate allocation contexts where spinning would be inappropriate or impossible to execute.
The technical implementation of this vulnerability resides in the page owner tracking subsystem which is designed to monitor and record stack traces of page allocations for debugging and performance analysis purposes. When the add_stack_record_to_list function is called from *_nolock() contexts such as alloc_pages_nolock_noprof, it attempts to acquire locks or perform operations that cannot succeed in these lock-free environments. The function fails to properly check the allocation context or handle the specific GFP flags that indicate the caller cannot safely spin or block. This creates a deadlock condition where the kernel thread becomes stuck in an infinite loop, effectively preventing the system from making forward progress in memory allocation operations. The flaw directly violates the principle of lock-free programming patterns and demonstrates poor error handling in kernel space memory management functions.
The operational impact of this vulnerability extends beyond simple system performance degradation to potentially complete system lockup or denial of service conditions. When the kernel enters this spin loop, it prevents any further page allocation operations from completing successfully, which can cascade into broader system instability. The vulnerability affects systems using the page owner tracking feature, which is typically enabled in debugging configurations or when specific kernel parameters are set to enable memory tracking. This creates a potential attack vector where malicious actors could trigger the condition through crafted memory allocation patterns, leading to system unresponsiveness or forced reboots. The vulnerability is particularly concerning because it operates at the kernel level where any malfunction can compromise entire system operations and is difficult to detect through standard monitoring systems.
Mitigation strategies for CVE-2025-68253 must address both immediate system protection and long-term code improvements. The primary solution involves modifying the add_stack_record_to_list function to properly detect when it is called from lock-free contexts and avoid spinning behavior in such scenarios. This can be achieved by checking the GFP flags passed to the function and implementing conditional logic that either defers the stack record creation or uses alternative non-blocking mechanisms. System administrators should consider disabling page owner tracking in production environments where this vulnerability could be exploited, though this reduces debugging capabilities. The fix should align with established kernel development practices and security guidelines, ensuring that similar issues do not occur in other kernel subsystems. This vulnerability also highlights the importance of proper lock-free programming patterns and the need for comprehensive testing of kernel code paths that may be invoked from different execution contexts, potentially relating to CWE-400 and CWE-691 security weaknesses.