I'm running KVM on a hardened gentoo system with PAX enabled. It happens sometimes (pretty often) that the ZFS module will crash when a KVM guest is cleanly shut down if the guest uses a ZVOL for storage. I have reproduced this issue running both ZFS 0.6.2-r3 from the ebuild and git master from the ebuild as well. So far I have tried disabling kernel-space ASLR but it didn't help. I will attach two dmesg outputs (while running zfs 0.6.2-r3 and zfs 9999) that I received and my kernel .config. Reproducible: Sometimes Steps to Reproduce: 1. Start a VM backed by ZFS storage 2. Shut it down cleanly (i.e. using poweroff in the guest) Actual Results: The ZFS module crashes. prometheus ~ # uname -a Linux prometheus 3.11.7-hardened-r1 #6 SMP PREEMPT Thu Jan 2 15:06:51 EST 2014 x86_64 Quad-Core AMD Opteron(tm) Processor 8356 AuthenticAMD GNU/Linux
Created attachment 366850 [details] dmesg output while using 0.6.2
Created attachment 366852 [details] dmesg output while using 9999
Created attachment 366854 [details] kernel configuration
There is an upstream issue for this: https://github.com/zfsonlinux/spl/commit/a3c1eb77721a0d511b4fe7111bb2314686570c4b This commit is believed to have fixed this: https://github.com/zfsonlinux/zfs/commit/a16878805388c4d96cb8a294de965071d138a47b In the future, I suggest filing kernel NULL pointer dereference reports upstream. I have been spending the time that I have for working on non-Gentoo specific ZFS bugs at the upstream tracker.
