UBUNTU-CVE-2026-90322: Low severity ubuntu/linux vulnerability

In the Linux kernel, the following vulnerability has been resolved: ocfs2/cluster: keep heartbeat local node stable o2nmnodelocalstore() handles local=0 by stopping o2net and setting cllocalnode to O2NMINVALIDNODENUM, but it leaves clhaslocal set. That stale state makes o2nmthisnode() return 255, blocks a later local=1 attempt with -EBUSY, and can feed 255 to heartbeat users that call o2nmthisnode() dynamically. Clearing clhaslocal is required when the local node is reset. But heartbeat threads can still be running at that point. They pin the local node config item at startup, yet o2hbdodiskheartbeat() and thread teardown re-read o2nmthisnode() for the local slot and for o2nmundependthisnode(). Once local=0 has cleared the live local-node state, those dynamic reads return O2NMMAXNODES, which is also the invalid node number 255. Store the local node number in the heartbeat region when the region starts. Use that stable node for heartbeat slot writes/checks, negotiation messages, and the final configfs undepend. Stop the heartbeat loop when the current local node no longer matches the stored node, and clear clhaslocal together with cllocalnode in the local=0 path so nodemanager state matches node removal. Validation reproduced this kernel report: KASAN slab-out-of-bounds in o2hbdodiskheartbeat+0x372/0xb30 RIP: 0010:memset+0xf/0x20 Read of size 8 Call trace: dumpstacklvl+0x66/0xa0 printreport+0xd0/0x630 o2hbdodiskheartbeat+0x372/0xb30 (fs/ocfs2/cluster/heartbeat.c:1079) srsoaliasreturnthunk+0x5/0xfbef5 virtaddrvalid+0x188/0x2f0 kasanreport+0xe4/0x120 o2hbdodiskheartbeat+0x5/0xb30 (fs/ocfs2/cluster/heartbeat.c:1079) o2hbthread+0x14e/0x770 kthreadaffinenode+0x139/0x180 lockdephardirqsonprepare+0xda/0x190 tracehardirqson+0x18/0x130 kthread+0x19d/0x1e0 retfromfork+0x37a/0x4d0 switchto+0x2d5/0x6f0 retfromforkasm+0x1a/0x30