From 42e9488971f26c07719e99e33d14811488d31632 Mon Sep 17 00:00:00 2001 From: Simon Horman Date: Thu, 21 May 2015 12:40:15 +0900 Subject: [PATCH] rocker: do not modify fdb table in rocker_port_fdb() when preparing transactions rocker_port_fdb_flush() may be called be called with trans == SWITCHDEV_TRANS_PREPARE and then trans == SWITCHDEV_TRANS_COMMIT from switchdev_port_attr_set() via switchdev_port_obj_add(). Adding the new entry to the FDB table when trans == SWITCHDEV_TRANS_PREPARE may result in a memory leak because when trans == SWITCHDEV_TRANS_PREPARE rocker_flow_tbl_bridge() will allocate memory when called via rocker_port_fdb_learn(). However, when trans == SWITCHDEV_TRANS_COMMIT the presence of the FDB entry in the FDB table causes rocker_port_fdb() to set the ROCKER_OP_FLAG_REFRESH flag which results in rocker_port_fdb_learn() skipping the call to rocker_flow_tbl_bridge() which would free the memory allocated by it when trans == SWITCHDEV_TRANS_PREPARE. ip link add br0 type bridge ip link set up dev eth0 ip link set dev eth0 master br0 bridge fdb add 52:54:00:12:35:08 dev eth0 bridge fdb add 52:54:00:12:35:09 dev eth0 [ 2.600730] ------------[ cut here ]------------ [ 2.601002] kernel BUG at drivers/net/ethernet/rocker/rocker.c:4369! [ 2.601373] invalid opcode: 0000 [#1] SMP [ 2.601963] Modules linked in: [ 2.602355] CPU: 0 PID: 64 Comm: bridge Not tainted 4.1.0-rc3-01048-g6d0f50c50211-dirty #1075 [ 2.602721] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.0-0-g4c59f5d-20150219_092859-nilsson.home.kraxel.org 04/01/2014 [ 2.602721] task: ffff880019facef0 ti: ffff88001f96c000 task.ti: ffff88001f96c000 [ 2.602721] RIP: 0010:[] [] rocker_port_obj_add+0x150/0x160 [ 2.602721] RSP: 0018:ffff88001f96fa98 EFLAGS: 00000212 [ 2.602721] RAX: ffff880019d4fa68 RBX: ffff88001f96fb18 RCX: 0000000000000000 [ 2.602721] RDX: ffff880019d4f000 RSI: ffff88001f96fb18 RDI: ffff880019d4f000 [ 2.602721] RBP: 0000000000000001 R08: 0000000000000000 R09: ffff88001f904620 [ 2.602721] R10: ffff88001f96fb60 R11: ffff880019e9d100 R12: ffff88001f96fb18 [ 2.602721] R13: ffff880019d4f680 R14: ffff88001f904610 R15: ffff8800198f7b80 [ 2.602721] FS: 00007f3eee917700(0000) GS:ffff88001b000000(0000) knlGS:0000000000000000 [ 2.602721] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2.602721] CR2: 00007f3eee4a15cb CR3: 000000001f933000 CR4: 00000000000006b0 [ 2.602721] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2.602721] DR3: 0000000000000000 DR6: 0000000000000000 DR7: 0000000000000000 [ 2.602721] Stack: [ 2.602721] 0000000000000000 ffff88001f96fb18 ffff880019d4f000 ffff88001f96fb18 [ 2.602721] ffff880019d4f000 ffffffff81332105 ffff88001f96fb50 ffffffff814464c0 [ 2.602721] ffff88001f96fb18 ffff88001f904600 ffff880019d4f000 ffffffff813326e5 [ 2.602721] Call Trace: [ 2.602721] [] ? __switchdev_port_obj_add+0x25/0x90 [ 2.602721] [] ? switchdev_port_obj_add+0x25/0xc0 [ 2.602721] [] ? switchdev_port_fdb_add+0x31/0x40 [ 2.602721] [] ? rtnl_fdb_add+0xff/0x1e0 [ 2.602721] [] ? rtnetlink_rcv_msg+0x7e/0x250 [ 2.602721] [] ? __skb_recv_datagram+0xfe/0x4b0 [ 2.602721] [] ? rtnetlink_rcv+0x30/0x30 [ 2.602721] [] ? netlink_rcv_skb+0xa8/0xd0 [ 2.602721] [] ? rtnetlink_rcv+0x1f/0x30 [ 2.602721] [] ? netlink_unicast+0x150/0x200 [ 2.602721] [] ? netlink_sendmsg+0x374/0x3e0 [ 2.602721] [] ? sock_sendmsg+0xf/0x30 [ 2.602721] [] ? ___sys_sendmsg+0x1f3/0x200 [ 2.602721] [] ? ___sys_recvmsg+0x105/0x140 [ 2.602721] [] ? SyS_readahead+0x90/0x90 [ 2.602721] [] ? filemap_map_pages+0x1ed/0x210 [ 2.602721] [] ? handle_mm_fault+0x5fc/0xe50 [ 2.602721] [] ? __sys_sendmsg+0x39/0x70 [ 2.602721] [] ? system_call_fastpath+0x12/0x6a [ 2.602721] Code: b7 8f a0 06 00 00 48 83 bf 88 06 00 00 00 74 1d 48 83 c4 08 89 ee 4c 89 ef 5b 5d 41 5c 41 5d 0f b7 c9 45 31 c0 e9 51 db ff ff 90 <0f> 0b b8 ea ff ff ff e9 cf fe ff ff 0f 1f 40 00 41 57 41 56 b9 [ 2.602721] RIP [] rocker_port_obj_add+0x150/0x160 [ 2.602721] RSP [ 2.615848] ---[ end trace 4f7b4f1c98077108 ]--- The above is resolved by not adding the new FDB entry to the FDB table if trans == SWITCHDEV_TRANS_PREPARE. For symmetry this patch also skips deleting FDB entries from the FDB table trans == SWITCHDEV_TRANS_PREPARE. However, my analysis is that this never occurs as trans is always SWITCHDEV_TRANS_NONE when removing FDB entries. Fixes: c4f20321d968 ("rocker: support prepare-commit transaction model") Acked-by: Scott Feldman Acked-by: Jiri Pirko Signed-off-by: Simon Horman Signed-off-by: David S. Miller --- drivers/net/ethernet/rocker/rocker.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c index ce1bfab077a7..89d22bdcbdc4 100644 --- a/drivers/net/ethernet/rocker/rocker.c +++ b/drivers/net/ethernet/rocker/rocker.c @@ -3612,9 +3612,11 @@ static int rocker_port_fdb(struct rocker_port *rocker_port, if (removing && found) { rocker_port_kfree(rocker_port, trans, fdb); - hash_del(&found->entry); + if (trans != SWITCHDEV_TRANS_PREPARE) + hash_del(&found->entry); } else if (!removing && !found) { - hash_add(rocker->fdb_tbl, &fdb->entry, fdb->key_crc32); + if (trans != SWITCHDEV_TRANS_PREPARE) + hash_add(rocker->fdb_tbl, &fdb->entry, fdb->key_crc32); } spin_unlock_irqrestore(&rocker->fdb_tbl_lock, lock_flags);