linux-raid.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jes Sorensen <jes.sorensen@gmail.com>
To: Andrea Righi <righi.andrea@gmail.com>
Cc: Robert LeBlanc <robert@leblancnet.us>, NeilBrown <neilb@suse.com>,
	linux-raid@vger.kernel.org
Subject: Re: [PATCH] Assemble: prevent segfault with faulty "best" devices
Date: Sun, 21 Jan 2018 16:38:40 -0500	[thread overview]
Message-ID: <536324bc-c198-d6f7-fc5a-0728d13e3132@gmail.com> (raw)
In-Reply-To: <20170808174807.GA6611@Dell>

On 08/08/2017 01:48 PM, Andrea Righi wrote:
> I was able to trigger this curious problem that seems to happen only on
> one of our server:
> 
> # mdadm --assemble /dev/md/10.4.237.12-volume --name 10.4.237.12-volume
> Segmentation fault
> 
> This md volume is a raid1 volume made of 2 device mapper (dm-multipath)
> devices and the underlying LUNs are imported via iSCSI.
> 
> Applying the following patch (see below) seems to fix the problem:
> 
> # ./mdadm --assemble /dev/md/10.4.237.12-volume --name 10.4.237.12-volume
> mdadm: /dev/md/10.4.237.12-volume has been started with 2 drives.
> 
> But I'm not sure if it's the right fix or if there're some other
> problems that I'm missing.
> 
> More details about the md superblocks that might help to better
> understand the nature of the problem:
> 
> # for i in 36001405a04ed0c104881{1,2}00000000000p2; do echo dev: ${i}; mdadm --examine /dev/mapper/${i}; done
> dev: 36001405a04ed0c104881100000000000p2
> /dev/mapper/36001405a04ed0c104881100000000000p2:
>           Magic : a92b4efc
>         Version : 1.2
>     Feature Map : 0x1
>      Array UUID : 5f3e8283:7f831b85:bc1958b9:6f2787a4
>            Name : 10.4.237.12-volume
>   Creation Time : Thu Jul 27 14:43:16 2017
>      Raid Level : raid1
>    Raid Devices : 2
> 
>  Avail Dev Size : 1073729503 (511.99 GiB 549.75 GB)
>      Array Size : 536864704 (511.99 GiB 549.75 GB)
>   Used Dev Size : 1073729408 (511.99 GiB 549.75 GB)
>     Data Offset : 8192 sectors
>    Super Offset : 8 sectors
>    Unused Space : before=8104 sectors, after=95 sectors
>           State : clean
>     Device UUID : 16dae7e3:42f3487f:fbeac43a:71cf1f63
> 
> Internal Bitmap : 8 sectors from superblock
>     Update Time : Tue Aug  8 11:12:22 2017
>   Bad Block Log : 512 entries available at offset 72 sectors
>        Checksum : 518c443e - correct
>          Events : 167
> 
> 
>    Device Role : Active device 0
>    Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
> dev: 36001405a04ed0c104881200000000000p2
> /dev/mapper/36001405a04ed0c104881200000000000p2:
>           Magic : a92b4efc
>         Version : 1.2
>     Feature Map : 0x1
>      Array UUID : 5f3e8283:7f831b85:bc1958b9:6f2787a4
>            Name : 10.4.237.12-volume
>   Creation Time : Thu Jul 27 14:43:16 2017
>      Raid Level : raid1
>    Raid Devices : 2
> 
>  Avail Dev Size : 1073729503 (511.99 GiB 549.75 GB)
>      Array Size : 536864704 (511.99 GiB 549.75 GB)
>   Used Dev Size : 1073729408 (511.99 GiB 549.75 GB)
>     Data Offset : 8192 sectors
>    Super Offset : 8 sectors
>    Unused Space : before=8104 sectors, after=95 sectors
>           State : clean
>     Device UUID : ef612bdd:e475fe02:5d3fc55e:53612f34
> 
> Internal Bitmap : 8 sectors from superblock
>     Update Time : Tue Aug  8 11:12:22 2017
>   Bad Block Log : 512 entries available at offset 72 sectors
>        Checksum : c39534fd - correct
>          Events : 167
> 
> 
>    Device Role : Active device 1
>    Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
> 
> # for i in 36001405a04ed0c104881{1,2}00000000000p2; do echo dev: ${i}; hexdump -s 4096 -n 4189696 -C /dev/mapper/${i}; done
> dev: 36001405a04ed0c104881100000000000p2
> 00001000  fc 4e 2b a9 01 00 00 00  01 00 00 00 00 00 00 00  |.N+.............|
> 00001010  5f 3e 82 83 7f 83 1b 85  bc 19 58 b9 6f 27 87 a4  |_>........X.o'..|
> 00001020  31 30 2e 34 2e 32 33 37  2e 31 32 2d 76 6f 6c 75  |10.4.237.12-volu|
> 00001030  6d 65 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |me..............|
> 00001040  64 50 7a 59 00 00 00 00  01 00 00 00 00 00 00 00  |dPzY............|
> 00001050  80 cf ff 3f 00 00 00 00  00 00 00 00 02 00 00 00  |...?............|
> 00001060  08 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> 00001070  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> 00001080  00 20 00 00 00 00 00 00  df cf ff 3f 00 00 00 00  |. .........?....|
> 00001090  08 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> 000010a0  00 00 00 00 00 00 00 00  16 da e7 e3 42 f3 48 7f  |............B.H.|
> 000010b0  fb ea c4 3a 71 cf 1f 63  00 00 08 00 48 00 00 00  |...:q..c....H...|
> 000010c0  54 f0 89 59 00 00 00 00  a7 00 00 00 00 00 00 00  |T..Y............|
> 000010d0  ff ff ff ff ff ff ff ff  9c 43 8c 51 80 00 00 00  |.........C.Q....|
> 000010e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> *
> 00001100  00 00 01 00 fe ff fe ff  fe ff fe ff fe ff fe ff  |................|
> 00001110  fe ff fe ff fe ff fe ff  fe ff fe ff fe ff fe ff  |................|
> *
> 00001200  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> *
> 00002000  62 69 74 6d 04 00 00 00  5f 3e 82 83 7f 83 1b 85  |bitm...._>......|
> 00002010  bc 19 58 b9 6f 27 87 a4  a7 00 00 00 00 00 00 00  |..X.o'..........|
> 00002020  a7 00 00 00 00 00 00 00  80 cf ff 3f 00 00 00 00  |...........?....|
> 00002030  00 00 00 00 00 00 00 01  05 00 00 00 00 00 00 00  |................|
> 00002040  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> *
> 00003100  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
> *
> 00004000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> *
> 003ffe00
> dev: 36001405a04ed0c104881200000000000p2
> 00001000  fc 4e 2b a9 01 00 00 00  01 00 00 00 00 00 00 00  |.N+.............|
> 00001010  5f 3e 82 83 7f 83 1b 85  bc 19 58 b9 6f 27 87 a4  |_>........X.o'..|
> 00001020  31 30 2e 34 2e 32 33 37  2e 31 32 2d 76 6f 6c 75  |10.4.237.12-volu|
> 00001030  6d 65 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |me..............|
> 00001040  64 50 7a 59 00 00 00 00  01 00 00 00 00 00 00 00  |dPzY............|
> 00001050  80 cf ff 3f 00 00 00 00  00 00 00 00 02 00 00 00  |...?............|
> 00001060  08 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> 00001070  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> 00001080  00 20 00 00 00 00 00 00  df cf ff 3f 00 00 00 00  |. .........?....|
> 00001090  08 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> 000010a0  01 00 00 00 00 00 00 00  ef 61 2b dd e4 75 fe 02  |.........a+..u..|
> 000010b0  5d 3f c5 5e 53 61 2f 34  00 00 08 00 48 00 00 00  |]?.^Sa/4....H...|
> 000010c0  54 f0 89 59 00 00 00 00  a7 00 00 00 00 00 00 00  |T..Y............|
> 000010d0  ff ff ff ff ff ff ff ff  5b 34 95 c3 80 00 00 00  |........[4......|
> 000010e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> *
> 00001100  00 00 01 00 fe ff fe ff  fe ff fe ff fe ff fe ff  |................|
> 00001110  fe ff fe ff fe ff fe ff  fe ff fe ff fe ff fe ff  |................|
> *
> 00001200  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> *
> 00002000  62 69 74 6d 04 00 00 00  5f 3e 82 83 7f 83 1b 85  |bitm...._>......|
> 00002010  bc 19 58 b9 6f 27 87 a4  a7 00 00 00 00 00 00 00  |..X.o'..........|
> 00002020  a7 00 00 00 00 00 00 00  80 cf ff 3f 00 00 00 00  |...........?....|
> 00002030  00 00 00 00 00 00 00 01  05 00 00 00 00 00 00 00  |................|
> 00002040  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> *
> 00003100  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
> *
> 00004000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> *
> 003ffe00
> 
> ---

Applied!

However, in the future, please do not use three dashes --- in a comment,
it messes up git am.

Oh and please use my gmail address for patches.

Thanks,
Jes


      parent reply	other threads:[~2018-01-21 21:38 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-08 17:48 [PATCH] Assemble: prevent segfault with faulty "best" devices Andrea Righi
2017-08-09  0:46 ` NeilBrown
2018-01-08 18:23   ` [PATCH resubmit] " Andrea Righi
2018-01-21 21:38 ` Jes Sorensen [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=536324bc-c198-d6f7-fc5a-0728d13e3132@gmail.com \
    --to=jes.sorensen@gmail.com \
    --cc=linux-raid@vger.kernel.org \
    --cc=neilb@suse.com \
    --cc=righi.andrea@gmail.com \
    --cc=robert@leblancnet.us \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).