CVE-2026-22989

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> nfsd: check that server is running in unlock_filesystem<br /> <br /> If we are trying to unlock the filesystem via an administrative<br /> interface and nfsd isn&amp;#39;t running, it crashes the server. This<br /> happens currently because nfsd4_revoke_states() access state<br /> structures (eg., conf_id_hashtbl) that has been freed as a part<br /> of the server shutdown.<br /> <br /> [ 59.465072] Call trace:<br /> [ 59.465308] nfsd4_revoke_states+0x1b4/0x898 [nfsd] (P)<br /> [ 59.465830] write_unlock_fs+0x258/0x440 [nfsd]<br /> [ 59.466278] nfsctl_transaction_write+0xb0/0x120 [nfsd]<br /> [ 59.466780] vfs_write+0x1f0/0x938<br /> [ 59.467088] ksys_write+0xfc/0x1f8<br /> [ 59.467395] __arm64_sys_write+0x74/0xb8<br /> [ 59.467746] invoke_syscall.constprop.0+0xdc/0x1e8<br /> [ 59.468177] do_el0_svc+0x154/0x1d8<br /> [ 59.468489] el0_svc+0x40/0xe0<br /> [ 59.468767] el0t_64_sync_handler+0xa0/0xe8<br /> [ 59.469138] el0t_64_sync+0x1ac/0x1b0<br /> <br /> Ensure this can&amp;#39;t happen by taking the nfsd_mutex and checking that<br /> the server is still up, and then holding the mutex across the call to<br /> nfsd4_revoke_states().