write_bitmap1 didn't check return value of locate_bitmap1, which will
operate bitmap area under invalid bitmap info.
mdadm core dumped when doing below steps:
```
node1 # mdadm -C /dev/md0 -b none -e 1.2 -n 2 -l mirror /dev/sda /dev/sdb
node1 # mdadm -Ss
node1 # mdadm -A -U home-cluster --home-cluster=abc /dev/md0 /dev/sda /dev/sdb
Floating point exception (core dumped)
```
Signed-off-by: Zhao Heming <heming.zhao@xxxxxxxx>
---
super1.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/super1.c b/super1.c
index 8b0d6ff..19fe6f5 100644
--- a/super1.c
+++ b/super1.c
@@ -2683,7 +2683,10 @@ static int write_bitmap1(struct supertype *st, int fd, enum bitmap_update update
init_afd(&afd, fd);
- locate_bitmap1(st, fd, 0);
+ if (locate_bitmap1(st, fd, 0) < 0) {
+ pr_err("Error: Invalid bitmap\n");
+ return -EINVAL;
+ }
if (posix_memalign(&buf, 4096, 4096))
return -ENOMEM;
--
2.29.2
