> -----Original Message-----
> From: [email protected] [mailto:ovs-dev-
> [email protected]] On Behalf Of Greg Rose
> Sent: Friday, May 26, 2017 11:51 PM
> To: [email protected]
> Subject: Re: [ovs-dev] [PATCH v2] netflow: Fix memory leak in
> netflow_unref.
>
> On Thu, 2017-05-25 at 21:05 -0700, Greg Rose wrote:
> > On Thu, 2017-05-25 at 09:53 -0700, Greg Rose wrote:
> > > On Mon, 2017-05-22 at 07:40 -0700, Greg Rose wrote:
> > > > On Mon, 2017-05-22 at 12:55 +0800, Yunjian Wang wrote:
> > > > > The memory leak was triggered each time on calling
> > > > > netflow_unref() with containing netflow_flows. And flows need to be
> removed and destroyed.
> > > > >
> > > > > Signed-off-by: Yunjian Wang <[email protected]>
> > > > > ---
> > > > > ofproto/netflow.c | 7 +++++++
> > > > > 1 file changed, 7 insertions(+)
> > > > >
> > > > > diff --git a/ofproto/netflow.c b/ofproto/netflow.c index
> > > > > 55f7814..29c5f3e 100644
> > > > > --- a/ofproto/netflow.c
> > > > > +++ b/ofproto/netflow.c
> > > > > @@ -409,10 +409,17 @@ netflow_ref(const struct netflow *nf_)
> > > > > void netflow_unref(struct netflow *nf) {
> > > > > + struct netflow_flow *nf_flow, *next;
> > > > > +
> > > > > if (nf && ovs_refcount_unref_relaxed(&nf->ref_cnt) == 1) {
> > > > > atomic_count_dec(&netflow_count);
> > > > > collectors_destroy(nf->collectors);
> > > > > ofpbuf_uninit(&nf->packet);
> > > > > + HMAP_FOR_EACH_SAFE (nf_flow, next, hmap_node, &nf-
> >flows) {
> > > > > + hmap_remove(&nf->flows, &nf_flow->hmap_node);
> > > > > + free(nf_flow);
> > > > > + }
> > > > > + hmap_destroy(&nf->flows);
> > > > > free(nf);
> > > > > }
> > > > > }
> > > >
> > > > This looks right to me. The only other place I see the flows
> > > > freed is when they're detected as idle. If the flow is never
> > > > detected as idle then I don't see anywhere else that they are
> > > > freed up after the xzalloc in netflow_flow_update().
> > > >
> > > > Reviewed-by: Greg Rose <[email protected]>
> > > >
> > >
> > > I'm trying to test this but the condition never seems to be met and
> > > thus the 4 lines of additional code free flows never executes. Is
> > > there some particular flow or type of network traffic that will execute
> > > this
> code?
> > >
> > > I'd like to add a Tested-by for this but unless I can get the code
> > > to execute I can't.
> > >
> > > - Greg
> >
> > OK, I've finally got my netflow configuration working right with
> > ntopng collecting the flows. I can test the patch tomorrow, it's
> > getting late for me now.
> >
> > Thanks,
> >
> > - Greg
>
> Actually, ntopng doesn't work as the flow collector itself (I spoke too
> soon) but I am successfully creating netflows which I can see with tcpdump.
> Then we are hitting the condition net netflow_unref() when I execute this
> command:
>
> ovs-vsctl clear Bridge int-br1 netflow
>
> However, the '*' marked lines of code are never executed when I place a gdb
> breakpoint on it:
>
> HMAP_FOR_EACH_SAFE (nf_flow, next, hmap_node, &nf->flows) {
> * hmap_remove(&nf->flows, &nf_flow->hmap_node);
> * free(nf_flow);
> }
>
> It seems the code is never reached. Unless we can see some example of the
> code being reached and executed I worry about this patch.
>
> Thanks,
>
> - Greg
It is probable that the need to test many times.
Thanks,
Yunjian
my ovs version: openvswitch-2.7.0
Test Script:
ovs-vsctl add-br ovs
ovs-vsctl add-port ovs eth1
for (( i=0; i<5000000; i=i+1 )); do
ovs-vsctl -- --id=@netflow create netflow targets=\"3.3.2.26:9996\"
active_timeout=30 -- set bridge ovs netflow=@netflow
sleep 3
ovs-vsctl clear bridge ovs netflow
sleep 1
done
Test results:
(gdb) b ofproto/netflow.c:419
Breakpoint 1 at 0x4aeb74: file ofproto/netflow.c, line 419.
(gdb) c
Continuing.
[Switching to Thread 0x7f09ed273700 (LWP 19046)]
Breakpoint 1, netflow_unref (nf=0x408dbd0) at ofproto/netflow.c:419
419 hmap_remove(&nf->flows, &nf_flow->hmap_node);
(gdb) bt
#0 netflow_unref (nf=0x408dbd0) at ofproto/netflow.c:419
#1 0x00000000004a4347 in xlate_cache_clear_netflow (netflow=0x408dbd0,
flow=0x7f09dc011a90) at ofproto/ofproto-dpif-xlate-cache.c:200
#2 0x00000000004a43e2 in xlate_cache_clear_entry (entry=0x7f09dc010d08) at
ofproto/ofproto-dpif-xlate-cache.c:221
#3 0x00000000004a44dc in xlate_cache_clear (xcache=0x7f09dc01ca90) at
ofproto/ofproto-dpif-xlate-cache.c:262
#4 0x00000000004a451e in xlate_cache_uninit (xcache=0x7f09dc01ca90) at
ofproto/ofproto-dpif-xlate-cache.c:271
#5 0x00000000004a4544 in xlate_cache_delete (xcache=0x7f09dc01ca90) at
ofproto/ofproto-dpif-xlate-cache.c:278
#6 0x00000000004911d9 in ukey_delete__ (ukey=0x40987d0) at
ofproto/ofproto-dpif-upcall.c:1801
#7 0x000000000056c9f5 in ovsrcu_call_postponed () at lib/ovs-rcu.c:323
#8 0x000000000056ca9b in ovsrcu_postpone_thread (arg=0x0) at lib/ovs-rcu.c:338
#9 0x000000000056efa0 in ovsthread_wrapper (aux_=0x3fa3c30) at
lib/ovs-thread.c:348
#10 0x00007f09f1e44dc5 in start_thread () from /usr/lib64/libpthread.so.0
#11 0x00007f09f0c0a71d in clone () from /usr/lib64/libc.so.6
(gdb) l
414 if (nf && ovs_refcount_unref_relaxed(&nf->ref_cnt) == 1) {
415 atomic_count_dec(&netflow_count);
416 collectors_destroy(nf->collectors);
417 ofpbuf_uninit(&nf->packet);
418 HMAP_FOR_EACH_SAFE (nf_flow, next, hmap_node,
&nf->flows) {
419 hmap_remove(&nf->flows, &nf_flow->hmap_node);
420 free(nf_flow);
421 }
422 free(nf);
423 }
(gdb) info b
Num Type Disp Enb Address What
1 breakpoint keep y 0x00000000004aeb74 in netflow_unref at
ofproto/netflow.c:419
breakpoint already hit 1 time
(gdb) p nf->flows
$1 = {buckets = 0x408dc50, one = 0x3fd1fd0, mask = 0, n = 1}
(gdb)
>
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