From: Vitaly Kuznetsov Date: Fri, 27 Feb 2015 19:25:51 +0000 (-0800) Subject: Drivers: hv: vmbus: prevent cpu offlining on newer hypervisors X-Git-Tag: omap-for-v4.1/fixes-rc1~73^2~125 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e513229b4c38;p=pandora-kernel.git Drivers: hv: vmbus: prevent cpu offlining on newer hypervisors When an SMP Hyper-V guest is running on top of 2012R2 Server and secondary cpus are sent offline (with echo 0 > /sys/devices/system/cpu/cpu$cpu/online) the system freeze is observed. This happens due to the fact that on newer hypervisors (Win8, WS2012R2, ...) vmbus channel handlers are distributed across all cpus (see init_vp_index() function in drivers/hv/channel_mgmt.c) and on cpu offlining nobody reassigns them to CPU0. Prevent cpu offlining when vmbus is loaded until the issue is fixed host-side. This patch also disables hibernation but it is OK as it is also broken (MCE error is hit on resume). Suspend still works. Tested with WS2008R2 and WS2012R2. Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed