On 11/21/2018 2:02 AM, Stephen Hemminger wrote:
On Tue, 20 Nov 2018 23:09:31 +0800
Jeff Guo <jia....@intel.com> wrote:
When device has been bound to igb_uio driver and application is running,
hot-unplugging the device may cause kernel crash.
Signed-off-by: Jeff Guo <jia....@intel.com>
---
doc/guides/rel_notes/known_issues.rst | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/doc/guides/rel_notes/known_issues.rst
b/doc/guides/rel_notes/known_issues.rst
index 95e4ce6..dfe0565 100644
--- a/doc/guides/rel_notes/known_issues.rst
+++ b/doc/guides/rel_notes/known_issues.rst
@@ -759,3 +759,24 @@ Netvsc driver and application restart
**Driver/Module**:
``uio_hv_generic`` module.
+
+
+kernel crash when hot-unplug igb_uio device while DPDK application is running
+-----------------------------------------------------------------------------
+
+**Description**:
+ When device has been bound to igb_uio driver and application is running,
hot-unplugging
+ the device may cause kernel crash.
+
+**Reason**:
+ When device is hot-unplugged, igb_uio driver will be removed which will
destroy uio resources.
+ Later trying to access any uio resource will cause kernel crash.
+
+**Resolution/Workaround**:
+ If using DPDK for PCI HW hot-unplug, prefer to bind device with VFIO
instead of IGB_UIO.
+
+**Affected Environment/Platform**:
+ ALL.
+
+**Driver/Module**:
+ ``igb_uio`` module.
Surely this is fixable. What is the back trace in the kernel? How can it be
reproduced with some
common hardware (or hypervisor). Will it happen with KVM?
I think the final fix should be at uio_module in the linux kernel, and
workaround could be in user space and igb_uio kernel driver if there is
a better one. So that is why we need a document here.
you could reference the back trace as below.
[ 1078.006709] RIP: 0010:uio_write+0x2e/0xc0 [uio]
[ 1078.006727] Call Trace: [ 1078.006765]
__vfs_write+0x18/0x40 [ 1078.006768]
vfs_write+0xb8/0x1b0 [ 1078.006770]
SyS_write+0x55/0xc0 [ 1078.006791]
entry_SYSCALL_64_fastpath+0x1e/0xad [ 1078.006793]
RIP: 0033:0x7f75a10224bd
you could check the whole info at below link which i have attach.
http://patches.dpdk.org/patch/47923/
The system env:
Host kernel: 4.17.0-041700rc1-generic
Vm kernel: Linux ubuntu 4.10.0-28-generic #32~16.04.2-Ubuntu.
QEMU emulator version: 2.5.0
DPDK: version: 18.11-rc4
NIC: ixgbe or i40e nic or other(igb_uio pci nic)
Reproduce step:
Host environment
1. Host: Bind port 0 to vfio-pci
modprobe vfio_pci
./usertools/dpdk-devbind.py -b vfio-pci 81:10.0
2. start qemu scripts
taskset -c 12-21 qemu-system-x86_64 \
-enable-kvm -m 8192 -smp cores=10,sockets=1 -cpu host -name dpdk1-vm1 \
-monitor stdio \
-drive file=/home/vm/ubuntu-14.04.img \
-device vfio-pci,host=0000:81:10.0,id=dev1 \
-netdev tap,id=ipvm1,ifname=tap5,script=/etc/qemu-ifup -device
rtl8139,netdev=ipvm1,id=net0,mac=00:00:00:00:00:01 \
-localtime -vnc :2
VM environment
1. Bind port 0 to igb_uio
./usertools/dpdk-devbind.py --st
./usertools/dpdk-devbind.py -b igb_uio 00:03.0
2. Start testpmd and enable hotplug feature
./x86_64-native-linuxapp-gcc/app/testpmd -c f -n 4 -- -i --hot-plug
3. testpmd>set fwd txonly
4. testpmd>start
5. Qemu: remove device for unplug:
(qemu) device_del dev1
6.Qemu : add device for plug:
(qemu) device_add vfio-pci,host=0000:81:10.0,id=dev1
7. Bind port 0 to igb_uio：
./usertools/dpdk-devbind.py -b igb_uio 00:03.0
8. testpmd>stop
9. testpmd>port attach 0000: 00:03.0
10. testpmd>port start all
11. testpmd>start
12. Repeat 5 -- 12 until the kernel crash occur.
