Re: [PATCH] migration/rdma: Fix cm event use after free

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Dr. David Alan Gilbert (dgilbert@redhat.com) wrote:
> * Li Zhijian (lizhijian@cn.fujitsu.com) wrote:
> > Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
> 
> Thanks! I don't think I understood that 'ack' actually meant 'free'!
> 
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Queued

> 
> > ---
> >  migration/rdma.c | 11 ++++++++---
> >  1 file changed, 8 insertions(+), 3 deletions(-)
> > 
> > diff --git a/migration/rdma.c b/migration/rdma.c
> > index 1cdb4561f32..d90b29a4b51 100644
> > --- a/migration/rdma.c
> > +++ b/migration/rdma.c
> > @@ -1539,16 +1539,20 @@ static int qemu_rdma_wait_comp_channel(RDMAContext *rdma)
> >  
> >                  if (pfds[1].revents) {
> >                      ret = rdma_get_cm_event(rdma->channel, &cm_event);
> > -                    if (!ret) {
> > -                        rdma_ack_cm_event(cm_event);
> > +                    if (ret) {
> > +                        error_report("failed to get cm event while wait "
> > +                                     "completion channel");
> > +                        return -EPIPE;
> >                      }
> >  
> >                      error_report("receive cm event while wait comp channel,"
> >                                   "cm event is %d", cm_event->event);
> >                      if (cm_event->event == RDMA_CM_EVENT_DISCONNECTED ||
> >                          cm_event->event == RDMA_CM_EVENT_DEVICE_REMOVAL) {
> > +                        rdma_ack_cm_event(cm_event);
> >                          return -EPIPE;
> >                      }
> > +                    rdma_ack_cm_event(cm_event);
> >                  }
> >                  break;
> >  
> > @@ -3285,7 +3289,6 @@ static void rdma_cm_poll_handler(void *opaque)
> >          error_report("get_cm_event failed %d", errno);
> >          return;
> >      }
> > -    rdma_ack_cm_event(cm_event);
> >  
> >      if (cm_event->event == RDMA_CM_EVENT_DISCONNECTED ||
> >          cm_event->event == RDMA_CM_EVENT_DEVICE_REMOVAL) {
> > @@ -3298,12 +3301,14 @@ static void rdma_cm_poll_handler(void *opaque)
> >                  rdma->return_path->error_state = -EPIPE;
> >              }
> >          }
> > +        rdma_ack_cm_event(cm_event);
> >  
> >          if (mis->migration_incoming_co) {
> >              qemu_coroutine_enter(mis->migration_incoming_co);
> >          }
> >          return;
> >      }
> > +    rdma_ack_cm_event(cm_event);
> >  }
> >  
> >  static int qemu_rdma_accept(RDMAContext *rdma)
> > -- 
> > 2.30.2
> > 
> > 
> > 
> -- 
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> 
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK