Re: [dpdk-dev] [PATCH] vhost: fix segfault as handle set_mem_table message

[Yuanhan Liu <yliu@fridaylinux.org>]

On Tue, Nov 28, 2017 at 01:09:29PM +0100, Maxime Coquelin wrote:
> 
> 
> On 11/15/2017 12:41 PM, Jianfeng Tan wrote:
> >In a running VM, operations (like device attach/detach) will
> >trigger the QEMU to resend set_mem_table to vhost-user backend.
> >
> >DPDK vhost-user handles this message rudely by unmap all existing
> >regions and map new ones. This might lead to segfault if there
> >is pmd thread just trying to touch those unmapped memory regions.
> >
> >But for most cases, except VM memory hotplug, QEMU still sends the
> >set_mem_table message even the memory regions are not changed as
> >QEMU vhost-user filters out those not backed by file (fd > 0).
> >
> >To fix this case, we add a check in the handler to see if the
> >memory regions are really changed; if not, we just keep old memory
> >regions.
> >
> >Fixes: 8f972312b8f4 ("vhost: support vhost-user")
> >
> >CC: stable@dpdk.org
> >
> >CC: Yuanhan Liu <yliu@fridaylinux.org>
> >CC: Maxime Coquelin <maxime.coquelin@redhat.com>
> >
> >Reported-by: Yang Zhang <zy107165@alibaba-inc.com>
> >Reported-by: Xin Long <longxin.xl@alibaba-inc.com>
> >Signed-off-by: Yi Yang <yi.y.yang@intel.com>
> >Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
> >---
> >  lib/librte_vhost/vhost_user.c | 33 +++++++++++++++++++++++++++++++++
> >  1 file changed, 33 insertions(+)
> 
> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Applied to dpdk-next-virtio.

Thanks.

	--yliu