Comment 28 for bug 359447

I'm running jaunty with everything up-to-date.

I was experiencing segfaults similar to those described in this ticket when disk I/O was high. For example, when dd'ing a raw image file to an LVM volume, when the image was about 60G, caused several kvm processes to crash.

I was able to reproduce these crashes in an interesting way:

I gave a FreeBSD VM an AoE volume, with the following command line:

/usr/bin/kvm -S -M pc -m 256 -smp 1 -name freebsd-test -uuid fa4f4230-ff42-012b-cef0-00163ec95f4c -monitor pty -boot c -drive file=/dev/mapper/vol1-freebsd--test,if=ide,index=0,boot=on -drive file=/dev/etherd/e0.1,if=ide,index=1 -net none -serial pty -parallel none -usb

Slightly prior to booting this VM, I would turn off the AoE volume where it was exported from. When FreeBSD would try to mount it, the kvm process would crash within about 30 seconds.

After installing the following ppa:

1:84+dfsg-0ubuntu12.1~rc2ppa3

I have not been able to reproduce the problem. Instead of the kvm process crashing, FreeBSD just reports a crap load of DMA errors:

[root@beta ~]# fsck /dev/ad1s1a
** /dev/ad1s1a
** Last Mounted on /backup
** Phase 1 - Check Blocks and Sizes
** Phase 2 - Check Pathnames
** Phase 3 - Check Connectivity
** Phase 4 - Check Reference Counts
** Phase 5 - Check Cyl groups
5939 files, 145406 used, 108409 free (2713 frags, 13212 blocks, 1.1% fragmentation)
ad1: FAILURE - WRITE_DMA status=41<READY,ERROR> error=4<ABORTED> LBA=191

CANNOT WRITE BLK: 128
CONTINUE? [yn] y

ad1: FAILURE - WRITE_DMA status=41<READY,ERROR> error=4<ABORTED> LBA=191
ad1: FAILURE - WRITE_DMA status=41<READY,ERROR> error=4<ABORTED> LBA=192
ad1: FAILURE - WRITE_DMA status=41<READY,ERROR> error=4<ABORTED> LBA=193
ad1: FAILURE - WRITE_DMA status=41<READY,ERROR> error=4<ABORTED> LBA=194
ad1: FAILURE - WRITE_DMA status=41<READY,ERROR> error=4<ABORTED> LBA=195
ad1: FAILURE - WRITE_DMA status=41<READY,ERROR> error=4<ABORTED> LBA=196
ad1: FAILURE - WRITE_DMA status=41<READY,ERROR> error=4<ABORTED> LBA=197

Since I pulled the rug from under it (probably equivalent to unplugging a real hard drive if this was a physical machine), I would expect these kinda of DMA errors.

So, all in all, +1 on this PPA.