From: Ido Schimmel idosch@mellanox.com
[ Upstream commit 7979457b1d3a069cd857f5bd69e070e30223dd0c ]
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 idosch@mellanox.com Reported-by: Stefan Priebe - Profihost AG s.priebe@profihost.ag Tested-by: Stefan Priebe - Profihost AG s.priebe@profihost.ag Acked-by: Nikolay Aleksandrov nikolay@cumulusnetworks.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/bridge/br_netlink.c | 1 + 1 file changed, 1 insertion(+)
--- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -612,6 +612,7 @@ int br_process_vlan_info(struct net_brid 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)