Bug in Btrfs File System on Linux Kernel Affecting Subpage Management

CVE-2023-53247

What is CVE-2023-53247?

A vulnerability in the Btrfs file system of the Linux kernel can lead to system panics and instability due to improper handling of page mapping during the file read operation. When the btrfs_cont_expand function attempts to manage subpage blocks, it may encounter a panic related to page state management. This issue arises when a page is set as mapped but later gets released, potentially leading to unexpected modifications and crashes. A proposed fix rectifies the order of operations to ensure that page states are safely managed, thus preventing the panic and maintaining system integrity during file operations.

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