Re: mdadm-3.2.5 coming soon :-(

[NeilBrown <neilb@suse.de>]

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On Tue, 15 May 2012 17:22:27 +0200 Maciej Naruszewicz
<maciej.naruszewicz@intel.com> wrote:

> > If anyone knows of any other issues that have cropped up wit 3.2.4, please
> > let me know.
> >
> > Thanks,
> > NeilBrown
> 
> Since mdadm-3.2.4 creating volumes using IMSM containers is impossible 
> (segfaults), unless the kernel is 3.1.x or higher (for instance 
> everything SEEMS to work in RHEL 7.0 Alpha and openSUSE 12.1). Full 
> story from SLES 11 SP2 (kernel-3.0.13-0.27-default) with mdadm-3.2.4 :
> 
> $ mdadm --zero-superblock /dev/sd[cd]
> $ mdadm -C /dev/md/imsm0 -a md -e imsm -n 2 /dev/sd[cd] -R
> 
>      [...]
> 
> $ tail /var/log/messages
> 
>      May 15 17:16:10 gklab-128-174 kernel: [  317.653470] md: bind<sdc>
>      May 15 17:16:10 gklab-128-174 kernel: [  317.653519] md: bind<sdd>
>      May 15 17:16:11 gklab-128-174 udevd-work[5249]: '/sbin/mdadm 
> --detail --export /dev/md127' unexpected exit with status 0x000b
>      May 15 17:16:11 gklab-128-174 kernel: [  317.701434] mdadm[5250]: 
> segfault at 78 ip 0000000000450c4f sp 00007fff6c99ada0 error 4 in 
> mdadm[400000+69000]
> 
> $ mdadm -C /dev/md/raid1_2disks -a md -l 1  --size 1500000 -n 2 
> /dev/sd[cd] -R -f
> 
>      mdadm: cannot open device: 11:0
>      [...]
>      mdadm: cannot open device: 11:0
>      [...]
>      Segmentation fault
> 
> $ tail /var/log/messages
> 
>      May 15 17:18:36 gklab-128-174 kernel: [  463.291235] mdadm[5298]: 
> segfault at 78 ip 0000000000450c4f sp 00007fff8ad887e0 error 4 in 
> mdadm[400000+69000]
> 
> Similiar story in RHEL 6.3 Beta, those errors don't happen with kernel 
>  >= 3.1.x though (or mdadm-3.2.3 :)).
> 
> Maciek N

Could the difference be that fact that 3.2.4 default to using /run, which
doens't exist on SLES11 and may on in RHEL 6.3?
If you compile with
   make MAP_DIR=/var/run/mdadm
does it work better?

However I think this will fix the crash you are seeing.

diff --git a/mapfile.c b/mapfile.c
index b890ed2..70ff355 100644
--- a/mapfile.c
+++ b/mapfile.c
@@ -404,6 +404,8 @@ void RebuildMap(void)
 			if (ok != 0)
 				continue;
 			info = st->ss->container_content(st, subarray);
+			if (!info)
+				continue;
 
 			if (md->devnum >= 0)
 				path = map_dev(MD_MAJOR, md->devnum, 0);

Thanks,
NeilBrown

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