netfs: Delete subtree of 'fs/netfs' when netfs module exits

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: netfs: Delete subtree of 'fs/netfs' when netfs module exits In netfs_init() or fscache_proc_init(), we create dentry under 'fs/netfs', but in netfs_exit(), we only delete the proc entry of 'fs/netfs' without deleting its subtree. This triggers the following WARNING: ================================================================== remove_proc_entry: removing non-empty directory 'fs/netfs', leaking at least 'requests' WARNING: CPU: 4 PID: 566 at fs/proc/generic.c:717 remove_proc_entry+0x160/0x1c0 Modules linked in: netfs(-) CPU: 4 UID: 0 PID: 566 Comm: rmmod Not tainted 6.11.0-rc3 #860 RIP: 0010:remove_proc_entry+0x160/0x1c0 Call Trace: <TASK> netfs_exit+0x12/0x620 [netfs] __do_sys_delete_module.isra.0+0x14c/0x2e0 do_syscall_64+0x4b/0x110 entry_SYSCALL_64_after_hwframe+0x76/0x7e ================================================================== Therefore use remove_proc_subtree() instead of remove_proc_entry() to fix the above problem.

References

• https://git.kernel.org/stable/c/603f95cefbee06a31b03137b777f03e3c2163d72
• https://git.kernel.org/stable/c/7a9eaf97d56625e55b31a7beb558e1ee185ca461
• https://git.kernel.org/stable/c/3c58a9575e02c2b90a3180007d57105ceaa7c246