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>

diff --git a/Incremental.c b/Incremental.c
index 09b94b9f58c17d501ddfc10f604d4f7a6331cba5..49a71f72af9513f494c82ce97bc0a4e61d8ce624 100644 (file)
--- 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)