On 14/05/2021 01.15, Dr. David Alan Gilbert wrote: > * Li Zhijian (lizhij...@cn.fujitsu.com) wrote: >> A segmentation fault was triggered when i try to abort a postcopy + rdma >> migration. >> >> since rdma_ack_cm_event releases a uninitialized cm_event in thise case. >> >> like below: >> 2496 ret = rdma_get_cm_event(rdma->channel, &cm_event); >> 2497 if (ret) { >> 2498 perror("rdma_get_cm_event after rdma_connect"); >> 2499 ERROR(errp, "connecting to destination!"); >> 2500 rdma_ack_cm_event(cm_event); <<<< cause segmentation fault >> 2501 goto err_rdma_source_connect; >> 2502 } >> >> Signed-off-by: Li Zhijian <lizhij...@cn.fujitsu.com> > OK, that's an easy fix then; but I wonder if we should perhaps remove > that rdma_ack_cm_event, if it's the get_cm_event that's failed?
I also wondered, i checked the man page get_cm_event(3) which has not documented and checked some rdma examples, some of them try to ack it[1], but some not[2]. [1]: https://github.com/linux-rdma/rdma-core/blob/e381334c2915a5290565694947790d4aebaf2222/librdmacm/examples/mckey.c#L451 [2]: https://github.com/linux-rdma/rdma-core/blob/e381334c2915a5290565694947790d4aebaf2222/librdmacm/examples/mckey.c#L342 Thanks > > Still, > > > Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > >> --- >> migration/rdma.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/migration/rdma.c b/migration/rdma.c >> index 00eac34232..2dadb62aed 100644 >> --- a/migration/rdma.c >> +++ b/migration/rdma.c >> @@ -2466,7 +2466,7 @@ static int qemu_rdma_connect(RDMAContext *rdma, Error >> **errp) >> .private_data = &cap, >> .private_data_len = sizeof(cap), >> }; >> - struct rdma_cm_event *cm_event; >> + struct rdma_cm_event *cm_event = NULL; >> int ret; >> >> /* >> -- >> 2.30.2 >> >> >>