diff mbox series

[5.6,021/118] net: bridge: vlan: Add a schedule point during VLAN processing

Message ID 20200513094419.579670715@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman May 13, 2020, 9:44 a.m. UTC 
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(+)
diff mbox series

Patch

--- 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)