On 8/17/26 4:20 AM, Travis Wu via dev wrote:
> pflow_output_get_debug() null-checks debug, ovs_cfg and br_int but reads
> sb_global->options unconditionally via smap_get_uint(). When
> ovn-controller connects to a Southbound DB that has no SB_Global row yet
> -- e.g. an HA bootstrap or failover where a cluster manager starts the SB
> and ovn-northd creates SB_Global moments later -- the engine recompute
> dereferences a NULL sb_global and crashes:
>
> smap_find <- smap_get_uint <- pflow_output_get_debug
> <- en_pflow_output_run <- engine_recompute <- engine_run
>
> The controller then crash-loops into its systemd start limit until northd
> populates SB_Global. Guard the dereference, matching the existing NULL
> checks in the same function.
>
> Signed-off-by: Travis Wu <[email protected]>
> ---
Hi Travis,
Thanks for the patch!
I'm not sure I understand how this happen (at least on the most recent
OVN main branch). We don't call engine_run() if there's no SB_Global
first record:
const struct sbrec_sb_global *sbg =
sbrec_sb_global_first(ovnsb_idl_loop.idl);
if (chassis && sbg && ovs_feature_set_discovered()) {
[...]
bool recompute_allowed = (ovnsb_idl_txn &&
!ofctrl_has_backlog());
engine_run(recompute_allowed);
So we should never reach pflow_output_get_debug() without a sb_global
record.
Are you hitting this on a recent version of OVN? That is, something
that includes:
https://github.com/ovn-org/ovn/commit/fa72572
Regards,
Dumitru
> controller/ovn-controller.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/controller/ovn-controller.c b/controller/ovn-controller.c
> index 6551a4e..9da2365 100644
> --- a/controller/ovn-controller.c
> +++ b/controller/ovn-controller.c
> @@ -4240,6 +4240,10 @@ pflow_output_get_debug(struct engine_node *node,
> struct physical_debug *debug)
> const struct sbrec_sb_global *sb_global =
> sbrec_sb_global_table_first(sb_global_table);
>
> + if (!sb_global) {
> + return;
> + }
> +
> if (!debug) {
> return;
> }
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