CVE-2026-89692

In the Linux kernel, the following vulnerability has been resolved:

nfsd: clear CALLBACK_RUNNING on failed delegation recall queue

nfsd_break_one_deleg() sets NFSD4_CALLBACK_RUNNING via test_and_set_bit

at entry to serialize recall work, then calls nfsd4_run_cb() to queue

the recall. When the queue attempt fails the refcount bump is undone,

but the RUNNING bit is left set. The only site that clears the bit is

nfsd41_destroy_cb() (fs/nfsd/nfs4callback.c), which runs from the

workqueue and is therefore unreachable when nothing was queued.

The bit becomes a permanent latch on dp->dl_recall.cb_flags: every

subsequent break_lease() on the same delegation hits the early-return

guard in nfsd_break_one_deleg() and silently skips the recall, so the

delegation is never broken and the conflicting open or lock stalls.

Fix by clearing NFSD4_CALLBACK_RUNNING on the !queued branch alongside

the refcount_dec.