From: Jakub Kicinski Date: Wed, 10 Jun 2026 14:20:27 +0000 (-0700) Subject: Merge branch 'bonding-3ad-fix-carrier-state-with-no-usable-slaves' X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a1a69c667c0293c4e61be00d03430655188ff62e;p=thirdparty%2Flinux.git Merge branch 'bonding-3ad-fix-carrier-state-with-no-usable-slaves' Louis Scalbert says: ==================== bonding: 3ad: fix carrier state with no usable slaves This series addresses a blackholing issue and a subsequent link-flapping issue in the 802.3ad bonding driver when dealing with inactive slaves and the `min_links` parameter. When an 802.3ad (LACP) bonding interface has no slaves in the collecting/distributing state, the bonding master still reports carrier as up as long as at least 'min_links' slaves have carrier. In this situation, only one slave is effectively used for TX/RX, while traffic received on other slaves is dropped. Upper-layer daemons therefore consider the interface operational, even though traffic may be blackholed if the lack of LACP negotiation means the partner is not ready to deal with traffic. This patchset introduces an optional behavior, widely adopted across the industry, to address this issue. It consists of bringing the bonding master interface down to signal to upper-layer processes that it is not usable. This patchset depends on the following iproute2 change: ip/bond: add lacp_strict support Link: https://lore.kernel.org/netdev/20260408152409.276358-1-louis.scalbert@6wind.com/ Patch 1 adds the missing IFLA_BOND_BROADCAST_NEIGH in if_link UAPI header. Patch 2 adds missing broadcast-neigh to YAML rt-link specs. Patch 3 introduces the lacp_strict configuration knob, which is applied in the subsequent patch. The default (off) mode preserves the existing behavior, while the strict mode (on) is intended to force the bonding master carrier down in this situation. Patch 4 addresses the core issue when lacp_strict is set to strict. It ensures that carrier is asserted only when at least 'min_links' slaves are in the Collecting/Distributing state. Patch 5 fixes a side effect of the previous patch. Tightening the carrier logic exposes a state persistence bug: when a physical link goes down, the LACP collecting/distributing flags remain set. When the link returns, the interface briefly hallucinates that it is ready, bounces the carrier up, and then drops it again once LACP renegotiation starts. Fix by resetting Collecting and Distributing state as soon as the link goes down. Patch 6 adds a test for bonding lacp_strict both modes. ==================== Link: https://patch.msgid.link/20260603150331.1919611-1-louis.scalbert@6wind.com Signed-off-by: Jakub Kicinski --- a1a69c667c0293c4e61be00d03430655188ff62e