From 890212d6800646153210ac264ce73035cc7dd5cc Mon Sep 17 00:00:00 2001
From: miaoguanqin <miaoguanqin@huawei.com>
Date: Tue, 4 Apr 2023 19:31:24 +0800
Subject: Fix null pointer for incremental in mdadm

when we excute mdadm --assemble, udev-md-raid-assembly.rules is triggered.
Then we stop array, we found an coredump for mdadm --incremental.func
stack are as follows:

#0  enough (level=10, raid_disks=4, layout=258, clean=1,
    avail=avail@entry=0x0) at util.c:555
#1  0x0000562170c26965 in Incremental (devlist=<optimized out>,
    c=<optimized out>, st=0x5621729b6dc0) at Incremental.c:514
#2  0x0000562170bfb6ff in main (argc=<optimized out>,
    argv=<optimized out>) at mdadm.c:1762

func enough() use array avail,avail allocate space in func count_active,
it may not alloc space, causing a coredump.We fix this coredump.

Signed-off-by: Guanqin Miao <miaoguanqin@huawei.com>
Signed-off-by: lixiaokeng <lixiaokeng@huawei.com>
Signed-off-by: Jes Sorensen <jes@trained-monkey.org>
---
 Incremental.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Incremental.c b/Incremental.c
index 09b94b9..49a71f7 100644
--- a/Incremental.c
+++ b/Incremental.c
@@ -507,6 +507,9 @@ int Incremental(struct mddev_dev *devlist, struct context *c,
 				    GET_OFFSET | GET_SIZE));
 	active_disks = count_active(st, sra, mdfd, &avail, &info);
 
+	if (!avail)
+		goto out_unlock;
+
 	journal_device_missing = (info.journal_device_required) && (info.journal_clean == 0);
 
 	if (info.consistency_policy == CONSISTENCY_POLICY_PPL)
-- 
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