the first bad commit:
commit 374f2981d1f10bc4307f250f24b2a7ddb9b14be0
Author: Paolo Bonzini <pbonz...@redhat.com>
Date: Fri May 17 12:37:03 2013 +0200
memory: protect current_map by RCU
Replace the flat_view_mutex with RCU, avoiding futex contention for
dataplane on large systems and many iothreads.
Reviewed-by: Fam Zheng <f...@redhat.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
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https://bugs.launchpad.net/bugs/1422285
Title:
The guest will be destroyed when hot plug the VF to guest for the
second time.
Status in QEMU:
New
Bug description:
Environment:
------------
Host OS (ia32/ia32e/IA64):ia32e
Guest OS (ia32/ia32e/IA64):ia32e
Guest OS Type (Linux/Windows):linux
kvm.git Commit: 6557bada461afeaa920a189fae2cff7c8fdce39f
qemu.kvm Commit: cd2d5541271f1934345d8ca42f5fafff1744eee7
Host Kernel Version:3.19.0-rc3
Hardware:Haswell_EP,Ivytown_EP
Bug detailed description:
--------------------------
create guest , then hot plug the VF to the guest for the second time, the
guest will be destroyed.
note:
1. hot plug the device to guest with vfio, the guest works fine
2.this should be a qemu bug:
kvm + qemu = result
6557bada + cd2d5541 = bad
6557bada + a805ca54 = good
Reproduce steps:
----------------
1. qemu-system-x86_64 -enable-kvm -m 2G -net none -monitor pty rhel6u5.qcow
2. echo "device_add pci-assign,host=03:10.1,id=nic" >/dev/pts/2
3. cat /dev/pts/2 &
4. echo "device_del nic" >/dev/pts/2
5. echo "device_add pci-assign,host=03:10.0,id=nic" >/dev/pts/2
Current result:
----------------
guest will be destroyed when hot plug the vf to guest for the second time.
Expected result:
----------------
guest works fine when hot plug the vf to guest for the second time
Basic root-causing log:
----------------------
[root@vt-hsw2 cathy]# qemu-system-x86_64 -enable-kvm -m 2G -net none -monitor
pty rhel6u5.qcow
char device redirected to /dev/pts/2 (label compat_monitor0)
Segmentation fault (core dumped)
some dmesg log:
pci-stub 0000:03:10.1: kvm deassign device
pci-stub 0000:03:10.1: enabling device (0000 -> 0002)
qemu-system-x86[9894]: segfault at 0 ip (null) sp 00007fa73df0cae8
error 14
pci-stub 0000:03:10.1: kvm assign device
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