graphic: 0.847
permissions: 0.838
KVM: 0.827
architecture: 0.824
assembly: 0.819
register: 0.819
device: 0.812
PID: 0.804
risc-v: 0.802
kernel: 0.797
files: 0.795
virtual: 0.791
socket: 0.788
debug: 0.786
arm: 0.782
user-level: 0.778
hypervisor: 0.778
performance: 0.774
network: 0.767
x86: 0.760
semantic: 0.759
VMM: 0.756
vnc: 0.753
peripherals: 0.739
ppc: 0.738
boot: 0.725
TCG: 0.716
mistranslation: 0.704
i386: 0.483

guest can't get IP when create guest with bridge.

Environment:
------------
Host OS (ia32/ia32e/IA64):ia32e
Guest OS (ia32/ia32e/IA64):ia32e
Guest OS Type (Linux/Windows):linux
kvm.git Commit:aefbef10e3ae6e2c6e3c54f906f10b34c73a2c66
qemu.git Commit:dc1e1350f8061021df765b396295329797d66933
Host Kernel Version:4.1.0
Hardware:Ivytown_EP, Haswell_EP


Bug detailed description:
--------------------------
when create guest with bridge, the guest can not get ip.

note:
1. fail rate: 3/5
2. this is a qemu bug:
kvm      + qemu   =  result
aefbef10 + dc1e1350    =  bad 
aefbef10 + a4ef02fd   =  good

Reproduce steps:
----------------
1. create guest:
qemu-system-x86_64 -enable-kvm -m 2G -smp 4 -device virtio-net-pci,netdev=net0,mac=$random_mac -netdev tap,id=net0,script=/etc/kvm/qemu-ifup rhel6u5.qcow

Current result:
----------------
guest can't get IP

Expected result:
----------------
guest can get ip

Basic root-causing log:
----------------------

the first bad commit is
commit a90a7425cf592a3afeff3eaf32f543b83050ee5c
Author: Fam Zheng <email address hidden>
Date:   Thu Jun 4 14:45:17 2015 +0800

    tap: Drop tap_can_send
    
    This callback is called by main loop before polling s->fd, if it returns
    false, the fd will not be polled in this iteration.
    
    This is redundant with checks inside read callback. After this patch,
    the data will be sent to peer when it arrives. If the device can't
    receive, it will be queued to incoming_queue, and when the device status
    changes, this queue will be flushed.
    
    Signed-off-by: Fam Zheng <email address hidden>
    Message-id: <email address hidden>
    Signed-off-by: Stefan Hajnoczi <email address hidden>

On Tue, 06/30 03:41, chao zhou wrote:
> the first bad commit is
> commit a90a7425cf592a3afeff3eaf32f543b83050ee5c
> Author: Fam Zheng <email address hidden>
> Date:   Thu Jun 4 14:45:17 2015 +0800
> 
>     tap: Drop tap_can_send
>     
>     This callback is called by main loop before polling s->fd, if it returns
>     false, the fd will not be polled in this iteration.
>     
>     This is redundant with checks inside read callback. After this patch,
>     the data will be sent to peer when it arrives. If the device can't
>     receive, it will be queued to incoming_queue, and when the device status
>     changes, this queue will be flushed.
>     
>     Signed-off-by: Fam Zheng <email address hidden>
>     Message-id: <email address hidden>
>     Signed-off-by: Stefan Hajnoczi <email address hidden>

Could you try this patch?

http://lists.nongnu.org/archive/html/qemu-devel/2015-06/msg07377.html

Fam


after try the patch http://lists.nongnu.org/archive/html/qemu-devel/2015-06/msg07377.html with qemu.git commit(d2966f804d70a244f5dde395fc5d22a50ed3e74e)
the guest can get IP, but after save/retore or live migration, the guest is alive, but ping or ssh  guest's IP fail .

On Wed, 07/01 06:36, chao zhou wrote:
> after try the patch
> http://lists.nongnu.org/archive/html/qemu-devel/2015-06/msg07377.html with
> qemu.git commit(d2966f804d70a244f5dde395fc5d22a50ed3e74e) the guest can get
> IP, but after save/retore or live migration, the guest is alive, but ping or
> ssh  guest's IP fail .

Another fix is needed to handle stop/resume. I'm sending it now with you in the
Cc list. Please test!

Thanks,
Fam

> 
> -- 
> You received this bug notification because you are a member of qemu-
> devel-ml, which is subscribed to QEMU.
> https://bugs.launchpad.net/bugs/1469946
> 
> Title:
>   guest can't get IP when create guest with bridge.
> 
> 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:aefbef10e3ae6e2c6e3c54f906f10b34c73a2c66
>   qemu.git Commit:dc1e1350f8061021df765b396295329797d66933
>   Host Kernel Version:4.1.0
>   Hardware:Ivytown_EP, Haswell_EP
> 
>   
>   Bug detailed description:
>   --------------------------
>   when create guest with bridge, the guest can not get ip.
> 
>   note:
>   1. fail rate: 3/5
>   2. this is a qemu bug:
>   kvm      + qemu   =  result
>   aefbef10 + dc1e1350    =  bad 
>   aefbef10 + a4ef02fd   =  good
> 
>   Reproduce steps:
>   ----------------
>   1. create guest:
>   qemu-system-x86_64 -enable-kvm -m 2G -smp 4 -device virtio-net-pci,netdev=net0,mac=$random_mac -netdev tap,id=net0,script=/etc/kvm/qemu-ifup rhel6u5.qcow
> 
>   Current result:
>   ----------------
>   guest can't get IP
> 
>   Expected result:
>   ----------------
>   guest can get ip
> 
>   Basic root-causing log:
>   ----------------------
> 
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/qemu/+bug/1469946/+subscriptions
> 


Since commit 6e99c63 "net/socket: Drop net_socket_can_send" and friends, net queues need to be explicitly flushed after qemu_can_send_packet() returns false, because the netdev side will disable the polling of fd.

This fixes the case of "cont" after "stop" (or migration), i.e.
vm_running changes to true, by listening to vm state changes.

Signed-off-by: Fam Zheng <email address hidden>
---
 include/net/net.h |  2 ++
 net/net.c         | 14 +++++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/net/net.h b/include/net/net.h index 6a6cbef..619a6e1 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -8,6 +8,7 @@
 #include "net/queue.h"
 #include "migration/vmstate.h"
 #include "qapi-types.h"
+#include "sysemu/sysemu.h"
 
 #define MAX_QUEUE_NUM 1024
 
@@ -92,6 +93,7 @@ struct NetClientState {
     NetClientDestructor *destructor;
     unsigned int queue_index;
     unsigned rxfilter_notify_enabled:1;
+    VMChangeStateEntry *vmcse;
 };
 
 typedef struct NICState {
diff --git a/net/net.c b/net/net.c
index 6ff7fec..edfa6a0 100644
--- a/net/net.c
+++ b/net/net.c
@@ -43,7 +43,6 @@
 #include "qapi-visit.h"
 #include "qapi/opts-visitor.h"
 #include "qapi/dealloc-visitor.h"
-#include "sysemu/sysemu.h"
 
 /* Net bridge is currently not supported for W32. */  #if !defined(_WIN32) @@ -263,6 +262,16 @@ static void qemu_net_client_destructor(NetClientState *nc)
     g_free(nc);
 }
 
+static void qemu_net_client_handle_vmstate(void *opaque,
+                                           int running,
+                                           RunState state) {
+    NetClientState *nc = opaque;
+    if (running && qemu_can_send_packet(nc) && nc->peer) {
+        qemu_flush_queued_packets(nc->peer);
+    }
+}
+
 static void qemu_net_client_setup(NetClientState *nc,
                                   NetClientInfo *info,
                                   NetClientState *peer, @@ -287,6 +296,8 @@ static void qemu_net_client_setup(NetClientState *nc,
 
     nc->incoming_queue = qemu_new_net_queue(nc);
     nc->destructor = destructor;
+    nc->vmcse = qemu_add_vm_change_state_handler(qemu_net_client_handle_vmstate,
+                                                 nc);
 }
 
 NetClientState *qemu_new_net_client(NetClientInfo *info, @@ -395,6 +406,7 @@ void qemu_del_net_client(NetClientState *nc)
                                           MAX_QUEUE_NUM);
     assert(queues != 0);
 
+    qemu_del_vm_change_state_handler(nc->vmcse);
     /* If there is a peer NIC, delete and cleanup client, but do not free. */
     if (nc->peer && nc->peer->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {
         NICState *nic = qemu_get_nic(nc->peer);
--
2.4.3



after try this patch and http://lists.nongnu.org/archive/html/qemu-devel/2015-06/msg07377.html  with qemu.git d2966f804d70a244f5dde395fc5d22a50ed3e74e
 after save/retore or live migration, the guest is alive,  ping or ssh guest's IP , it is fine


Does the bug's patch has merged in qemu.git?
I test the latest qemu.git(commit:5b5e8cdd7da7a2214dd062afff5b866234aab228), the bug still can reproduce.

On Mon, Jul 20, 2015 at 07:46:55AM -0000, chao zhou wrote:
> Does the bug's patch has merged in qemu.git?
> I test the latest qemu.git(commit:5b5e8cdd7da7a2214dd062afff5b866234aab228), the bug still can reproduce.

Please git fetch origin and try again.


The patch mentioned earlier has been committed here:
https://git.qemu.org/?p=qemu.git;a=commitdiff;h=625de449fc5597f2e1aff
... so I think we can mark this as fixed now.