Executive Summary

This vulnerability in the Linux kernel's vhost/vsock component occurs because the kernel's memory allocator (kmalloc) fails when trying to allocate large memory regions (such as 32kB packets) needed during data transfer over vsock, like when copying large files over sftp. The failure leads to page allocation errors. The fix involves using kvmalloc/kvfree, which better handles larger memory allocations.

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Impact Analysis

This vulnerability can cause failures in memory allocation during large data transfers over vsock, potentially leading to errors or crashes in the affected Linux kernel component. This could disrupt data transfer operations such as sftp over vsock, impacting system stability or performance.

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Detection Guidance

This vulnerability can be detected by monitoring kernel logs for page allocation failures related to vhost/vsock, specifically messages indicating kmalloc failures when handling large packets (around 32kB). You can check the kernel log using commands like 'dmesg | grep vhost_vsock' or 'journalctl -k | grep vhost_vsock' to look for error traces similar to the provided call trace involving kmalloc failures.

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Mitigation Strategies

The immediate mitigation is to apply the fix that replaces kmalloc with kvmalloc/kvfree for larger packets in the vhost/vsock code. This workaround addresses the page allocation failure by using kvmalloc instead of kmalloc for large memory allocations.

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