Commit 9e3072e3 authored Jul 10, 2015 by Guoqing Jiang Committed by NeilBrown Aug 31, 2015

md-cluster: init suspend_list and suspend_lock early in join



If the node just join the cluster, and receive the msg from other nodes
before init suspend_list, it will cause kernel crash due to NULL pointer
dereference, so move the initializations early to fix the bug.

md-cluster: Joined cluster 3578507b-e0cb-6d4f-6322-696cd7b1b10c slot 3
BUG: unable to handle kernel NULL pointer dereference at           (null)
... ... ...
Call Trace:
[<ffffffffa0444924>] process_recvd_msg+0x2e4/0x330 [md_cluster]
[<ffffffffa0444a06>] recv_daemon+0x96/0x170 [md_cluster]
[<ffffffffa045189d>] md_thread+0x11d/0x170 [md_mod]
[<ffffffff810768c4>] kthread+0xb4/0xc0
[<ffffffff8151927c>] ret_from_fork+0x7c/0xb0
... ... ...
RIP  [<ffffffffa0443581>] __remove_suspend_info+0x11/0xa0 [md_cluster]

Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: NeilBrown <neilb@suse.com>

parent b5ef5678

drivers/md/md-cluster.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -671,6 +671,8 @@ static int join(struct mddev *mddev, int nodes)
		if (!cinfo)
		return -ENOMEM;

		INIT_LIST_HEAD(&cinfo->suspend_list);
		spin_lock_init(&cinfo->suspend_lock);
		init_completion(&cinfo->completion);

		mutex_init(&cinfo->sb_mutex);
		@@ -736,9 +738,6 @@ static int join(struct mddev *mddev, int nodes)
		goto err;
		}

		INIT_LIST_HEAD(&cinfo->suspend_list);
		spin_lock_init(&cinfo->suspend_lock);

		ret = gather_all_resync_info(mddev, nodes);
		if (ret)
		goto err;

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