From 7979457b1d3a069cd857f5bd69e070e30223dd0c Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Thu, 30 Apr 2020 22:38:45 +0300 Subject: [PATCH] net: bridge: vlan: Add a schedule point during VLAN processing User space can request to delete a range of VLANs from a bridge slave in one netlink request. For each deleted VLAN the FDB needs to be traversed in order to flush all the affected entries. If a large range of VLANs is deleted and the number of FDB entries is large or the FDB lock is contented, it is possible for the kernel to loop through the deleted VLANs for a long time. In case preemption is disabled, this can result in a soft lockup. Fix this by adding a schedule point after each VLAN is deleted to yield the CPU, if needed. This is safe because the VLANs are traversed in process context. Fixes: bdced7ef7838 ("bridge: support for multiple vlans and vlan ranges in setlink and dellink requests") Signed-off-by: Ido Schimmel Reported-by: Stefan Priebe - Profihost AG Tested-by: Stefan Priebe - Profihost AG Acked-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- net/bridge/br_netlink.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index 43dab4066f91..a0f5dbee8f9c 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -612,6 +612,7 @@ int br_process_vlan_info(struct net_bridge *br, v - 1, rtm_cmd); v_change_start = 0; } + cond_resched(); } /* v_change_start is set only if the last/whole range changed */ if (v_change_start)