Re: [PATCH v2] ocfs2/cluster: keep heartbeat local node stable

[Joseph Qi]

On 6/16/26 3:49 PM, Cen Zhang wrote:
> o2nm_node_local_store() handles local=0 by stopping o2net and setting
> cl_local_node to O2NM_INVALID_NODE_NUM, but it leaves cl_has_local set.
> That stale state makes o2nm_this_node() return 255, blocks a later
> local=1 attempt with -EBUSY, and can feed 255 to heartbeat users that
> call o2nm_this_node() dynamically.
> 
> Clearing cl_has_local 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 o2hb_do_disk_heartbeat() and thread
> teardown re-read o2nm_this_node() for the local slot and for
> o2nm_undepend_this_node(). Once local=0 has cleared the live local-node
> state, those dynamic reads return O2NM_MAX_NODES, 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 cl_has_local together with cl_local_node in the local=0
> path so nodemanager state matches node removal.
> 
> Validation reproduced this kernel report:
> KASAN slab-out-of-bounds in o2hb_do_disk_heartbeat+0x372/0xb30
> RIP: 0010:memset+0xf/0x20
> Read of size 8
> Call trace:
>   dump_stack_lvl+0x66/0xa0
>   print_report+0xd0/0x630
>   o2hb_do_disk_heartbeat+0x372/0xb30 (fs/ocfs2/cluster/heartbeat.c:1079)
>   srso_alias_return_thunk+0x5/0xfbef5
>   __virt_addr_valid+0x188/0x2f0
>   kasan_report+0xe4/0x120
>   o2hb_do_disk_heartbeat+0x5/0xb30 (fs/ocfs2/cluster/heartbeat.c:1079)
>   o2hb_thread+0x14e/0x770
>   kthread_affine_node+0x139/0x180
>   lockdep_hardirqs_on_prepare+0xda/0x190
>   trace_hardirqs_on+0x18/0x130
>   kthread+0x19d/0x1e0
>   ret_from_fork+0x37a/0x4d0
>   __switch_to+0x2d5/0x6f0
>   ret_from_fork_asm+0x1a/0x30
> 
> Suggested-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
> Fixes: a7f6a5fb4bde ("[PATCH] OCFS2: The Second Oracle Cluster Filesystem")
> Assisted-by: Codex:gpt-5.5
> Signed-off-by: Cen Zhang <zzzccc427@xxxxxxxxx>

Looks fine.
Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>

> ---
> Changes since v1:
> - Clear cluster->cl_has_local in the local=0 path as suggested by Joseph.
> - Replace the broader heartbeat active-state approach with a stable local
>   node number stored in each heartbeat region while the heartbeat thread is
>   running.
> 
>  fs/ocfs2/cluster/heartbeat.c   | 43 +++++++++++++++++++++++-----------
>  fs/ocfs2/cluster/nodemanager.c | 19 +++++++++++----
>  fs/ocfs2/cluster/nodemanager.h |  2 ++
>  3 files changed, 46 insertions(+), 18 deletions(-)
> 
> diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
> index d12784aaaa4b..6da96a374fcd 100644
> --- a/fs/ocfs2/cluster/heartbeat.c
> +++ b/fs/ocfs2/cluster/heartbeat.c
> @@ -202,8 +202,9 @@ struct o2hb_region {
>  				hr_node_deleted:1;
>  
>  	/* protected by the hr_callback_sem */
>  	struct task_struct 	*hr_task;
> +	u8			hr_node_num;
>  
>  	unsigned int		hr_blocks;
>  	unsigned long long	hr_start_block;
>  
> @@ -349,14 +350,14 @@ static void o2hb_disarm_timeout(struct o2hb_region *reg)
>  	cancel_delayed_work_sync(&reg->hr_write_timeout_work);
>  	cancel_delayed_work_sync(&reg->hr_nego_timeout_work);
>  }
>  
> -static int o2hb_send_nego_msg(int key, int type, u8 target)
> +static int o2hb_send_nego_msg(int key, int type, u8 target, u8 node_num)
>  {
>  	struct o2hb_nego_msg msg;
>  	int status, ret;
>  
> -	msg.node_num = o2nm_this_node();
> +	msg.node_num = node_num;
>  again:
>  	ret = o2net_send_message(type, key, &msg, sizeof(msg),
>  			target, &status);
>  
> @@ -372,10 +373,12 @@ static void o2hb_nego_timeout(struct work_struct *work)
>  {
>  	unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
>  	int master_node, i, ret;
>  	struct o2hb_region *reg;
> +	u8 node_num;
>  
>  	reg = container_of(work, struct o2hb_region, hr_nego_timeout_work.work);
> +	node_num = reg->hr_node_num;
>  	/* don't negotiate timeout if last hb failed since it is very
>  	 * possible io failed. Should let write timeout fence self.
>  	 */
>  	if (reg->hr_last_hb_status)
> @@ -384,12 +387,12 @@ static void o2hb_nego_timeout(struct work_struct *work)
>  	o2hb_fill_node_map(live_node_bitmap, O2NM_MAX_NODES);
>  	/* lowest node as master node to make negotiate decision. */
>  	master_node = find_first_bit(live_node_bitmap, O2NM_MAX_NODES);
>  
> -	if (master_node == o2nm_this_node()) {
> +	if (master_node == node_num) {
>  		if (!test_bit(master_node, reg->hr_nego_node_bitmap)) {
>  			printk(KERN_NOTICE "o2hb: node %d hb write hung for %ds on region %s (%pg).\n",
> -				o2nm_this_node(), O2HB_NEGO_TIMEOUT_MS/1000,
> +				node_num, O2HB_NEGO_TIMEOUT_MS / 1000,
>  				config_item_name(&reg->hr_item), reg_bdev(reg));
>  			set_bit(master_node, reg->hr_nego_node_bitmap);
>  		}
>  		if (!bitmap_equal(reg->hr_nego_node_bitmap, live_node_bitmap,
> @@ -416,20 +419,20 @@ static void o2hb_nego_timeout(struct work_struct *work)
>  				continue;
>  
>  			mlog(ML_HEARTBEAT, "send NEGO_APPROVE msg to node %d\n", i);
>  			ret = o2hb_send_nego_msg(reg->hr_key,
> -					O2HB_NEGO_APPROVE_MSG, i);
> +					O2HB_NEGO_APPROVE_MSG, i, node_num);
>  			if (ret)
>  				mlog(ML_ERROR, "send NEGO_APPROVE msg to node %d fail %d\n",
>  					i, ret);
>  		}
>  	} else {
>  		/* negotiate timeout with master node. */
>  		printk(KERN_NOTICE "o2hb: node %d hb write hung for %ds on region %s (%pg), negotiate timeout with node %d.\n",
> -			o2nm_this_node(), O2HB_NEGO_TIMEOUT_MS/1000, config_item_name(&reg->hr_item),
> +			node_num, O2HB_NEGO_TIMEOUT_MS / 1000, config_item_name(&reg->hr_item),
>  			reg_bdev(reg), master_node);
>  		ret = o2hb_send_nego_msg(reg->hr_key, O2HB_NEGO_TIMEOUT_MSG,
> -				master_node);
> +				master_node, node_num);
>  		if (ret)
>  			mlog(ML_ERROR, "send NEGO_TIMEOUT msg to node %d fail %d\n",
>  				master_node, ret);
>  	}
> @@ -600,9 +603,11 @@ static int o2hb_issue_node_write(struct o2hb_region *reg,
>  	struct bio *bio;
>  
>  	o2hb_bio_wait_init(write_wc);
>  
> -	slot = o2nm_this_node();
> +	slot = reg->hr_node_num;
> +	if (slot >= O2NM_MAX_NODES)
> +		return -EINVAL;
>  
>  	bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1,
>  				 REQ_OP_WRITE | REQ_SYNC);
>  	if (IS_ERR(bio)) {
> @@ -669,10 +674,14 @@ static int o2hb_check_own_slot(struct o2hb_region *reg)
>  {
>  	struct o2hb_disk_slot *slot;
>  	struct o2hb_disk_heartbeat_block *hb_block;
>  	char *errstr;
> +	u8 node_num = reg->hr_node_num;
> +
> +	if (node_num >= O2NM_MAX_NODES)
> +		return 0;
>  
> -	slot = &reg->hr_slots[o2nm_this_node()];
> +	slot = &reg->hr_slots[node_num];
>  	/* Don't check on our 1st timestamp */
>  	if (!slot->ds_last_time)
>  		return 0;
>  
> @@ -711,9 +720,12 @@ static inline void o2hb_prepare_block(struct o2hb_region *reg,
>  	u64 cputime;
>  	struct o2hb_disk_slot *slot;
>  	struct o2hb_disk_heartbeat_block *hb_block;
>  
> -	node_num = o2nm_this_node();
> +	node_num = reg->hr_node_num;
> +	if (node_num >= O2NM_MAX_NODES)
> +		return;
> +
>  	slot = &reg->hr_slots[node_num];
>  
>  	hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
>  	memset(hb_block, 0, reg->hr_block_bytes);
> @@ -1205,18 +1217,19 @@ static int o2hb_thread(void *data)
>  
>  	set_user_nice(current, MIN_NICE);
>  
>  	/* Pin node */
> -	ret = o2nm_depend_this_node();
> +	ret = o2nm_depend_node(reg->hr_node_num);
>  	if (ret) {
>  		mlog(ML_ERROR, "Node has been deleted, ret = %d\n", ret);
>  		reg->hr_node_deleted = 1;
>  		wake_up(&o2hb_steady_queue);
>  		return 0;
>  	}
>  
>  	while (!kthread_should_stop() &&
> -	       !reg->hr_unclean_stop && !reg->hr_aborted_start) {
> +	       !reg->hr_unclean_stop && !reg->hr_aborted_start &&
> +	       o2nm_this_node() == reg->hr_node_num) {
>  		/* We track the time spent inside
>  		 * o2hb_do_disk_heartbeat so that we avoid more than
>  		 * hr_timeout_ms between disk writes. On busy systems
>  		 * this should result in a heartbeat which is less
> @@ -1263,9 +1276,9 @@ static int o2hb_thread(void *data)
>  			mlog_errno(ret);
>  	}
>  
>  	/* Unpin node */
> -	o2nm_undepend_this_node();
> +	o2nm_undepend_node(reg->hr_node_num);
>  
>  	mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
>  
>  	return 0;
> @@ -1790,9 +1803,10 @@ static ssize_t o2hb_region_dev_store(struct config_item *item,
>  		return -EINVAL;
>  
>  	/* We can't heartbeat without having had our node number
>  	 * configured yet. */
> -	if (o2nm_this_node() == O2NM_MAX_NODES)
> +	reg->hr_node_num = o2nm_this_node();
> +	if (reg->hr_node_num == O2NM_MAX_NODES)
>  		return -EINVAL;
>  
>  	ret = kstrtol(p, 0, &fd);
>  	if (ret < 0)
> @@ -2035,8 +2049,9 @@ static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *g
>  	if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
>  		ret = -ENAMETOOLONG;
>  		goto free;
>  	}
> +	reg->hr_node_num = O2NM_MAX_NODES;
>  
>  	spin_lock(&o2hb_live_lock);
>  	reg->hr_region_num = 0;
>  	if (o2hb_global_heartbeat_active()) {
> diff --git a/fs/ocfs2/cluster/nodemanager.c b/fs/ocfs2/cluster/nodemanager.c
> index 402563154550..e1f8f577ce5d 100644
> --- a/fs/ocfs2/cluster/nodemanager.c
> +++ b/fs/ocfs2/cluster/nodemanager.c
> @@ -366,8 +366,9 @@ static ssize_t o2nm_node_local_store(struct config_item *item, const char *page,
>  
>  	if (!tmp && cluster->cl_has_local &&
>  	    cluster->cl_local_node == node->nd_num) {
>  		o2net_stop_listening(node);
> +		cluster->cl_has_local = 0;
>  		cluster->cl_local_node = O2NM_INVALID_NODE_NUM;
>  	}
>  
>  	node->nd_local = tmp;
> @@ -781,14 +782,14 @@ void o2nm_undepend_item(struct config_item *item)
>  {
>  	configfs_undepend_item(item);
>  }
>  
> -int o2nm_depend_this_node(void)
> +int o2nm_depend_node(u8 node_num)
>  {
>  	int ret = 0;
>  	struct o2nm_node *local_node;
>  
> -	local_node = o2nm_get_node_by_num(o2nm_this_node());
> +	local_node = o2nm_get_node_by_num(node_num);
>  	if (!local_node) {
>  		ret = -EINVAL;
>  		goto out;
>  	}
> @@ -799,19 +800,29 @@ int o2nm_depend_this_node(void)
>  out:
>  	return ret;
>  }
>  
> -void o2nm_undepend_this_node(void)
> +void o2nm_undepend_node(u8 node_num)
>  {
>  	struct o2nm_node *local_node;
>  
> -	local_node = o2nm_get_node_by_num(o2nm_this_node());
> +	local_node = o2nm_get_node_by_num(node_num);
>  	BUG_ON(!local_node);
>  
>  	o2nm_undepend_item(&local_node->nd_item);
>  	o2nm_node_put(local_node);
>  }
>  
> +int o2nm_depend_this_node(void)
> +{
> +	return o2nm_depend_node(o2nm_this_node());
> +}
> +
> +void o2nm_undepend_this_node(void)
> +{
> +	o2nm_undepend_node(o2nm_this_node());
> +}
> +
>  
>  static void __exit exit_o2nm(void)
>  {
>  	/* XXX sync with hb callbacks and shut down hb? */
> diff --git a/fs/ocfs2/cluster/nodemanager.h b/fs/ocfs2/cluster/nodemanager.h
> index 3490e77a952d..39006005427b 100644
> --- a/fs/ocfs2/cluster/nodemanager.h
> +++ b/fs/ocfs2/cluster/nodemanager.h
> @@ -64,8 +64,10 @@ void o2nm_node_get(struct o2nm_node *node);
>  void o2nm_node_put(struct o2nm_node *node);
>  
>  int o2nm_depend_item(struct config_item *item);
>  void o2nm_undepend_item(struct config_item *item);
> +int o2nm_depend_node(u8 node_num);
> +void o2nm_undepend_node(u8 node_num);
>  int o2nm_depend_this_node(void);
>  void o2nm_undepend_this_node(void);
>  
>  #endif /* O2CLUSTER_NODEMANAGER_H */