[Bug 529510] [NEW] kcryptd using 100% IO load

[Bodo Bellut]

Public bug reported:

Hi,

my setup is like this:

4 SATA disks are configured as a software RAID5, the complete RAID is encrypted using LUKS and inside this LUKS containers is one volume group with several LVs.
There's also one eSATA disk using LUKS but no RAID or LVM.

When writing to the eSATA disk everything works smoothly.

When reading from the RAID everything works smoothly.

But when writing larger amounts of data (e.g. an rsync running over a
100 MBit/s network link) to the RAID I see kcryptd going into
uninterruptible sleep (D) state and consuming 100% CPU load (IO wait).
If I don't stop the data the system crashes soon after, last overall
system load displayed is about 8 (normal idle load is 0.2 on this
system).

When I'm using GRML 2009.10 in the same system I can write with full
speed to the RAID, tested from the eSATA disk.

I've tried renicing kblockd and kcryptd to 15 according to https://lists
.linux-foundation.org/pipermail/bugme-new/2007-June/016431.html which
somewhat seems to lessen the impact, at least I have the chance to stop
the data coming in before the system crashes this way.

There's nothing in dmesg whatsoever.

$ uname -a
Linux sakura 2.6.31-19-generic #56-Ubuntu SMP Thu Jan 28 02:39:34 UTC 2010 x86_64 GNU/Linux

$ cat /proc/version_signature 
Ubuntu 2.6.31-19.56-generic

$ apt-cache policy linux
linux:
  Installed: (none)
  Candidate: 2.6.31.19.32
  Version table:
     2.6.31.19.32 0
        500 http://de.archive.ubuntu.com karmic-updates/main Packages
        500 http://security.ubuntu.com karmic-security/main Packages
     2.6.31.14.27 0
        500 http://de.archive.ubuntu.com karmic/main Packages

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 9.10
Release:	9.10
Codename:	karmic

regards,
Bodo

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

-- 
kcryptd using 100% IO load
https://bugs.launchpad.net/bugs/529510
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