rds: prevent dereference of a NULL device Binding might result in a NULL device, which is dereferenced causing this BUG: [ 1317.260548] BUG: unable to handle kernel NULL pointer dereference at 0000000000000974 [ 1317.261847] IP: [<ffffffff84225f52>] rds_ib_laddr_check+0x82/0x110 [ 1317.263315] PGD 418bcb067 PUD 3ceb21067 PMD 0 [ 1317.263502] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 1317.264179] Dumping ftrace buffer: [ 1317.264774] (ftrace buffer empty) [ 1317.265220] Modules linked in: [ 1317.265824] CPU: 4 PID: 836 Comm: trinity-child46 Tainted: G W 3.13.0-rc4- next-20131218-sasha-00013-g2cebb9b-dirty #4159 [ 1317.267415] task: ffff8803ddf33000 ti: ffff8803cd31a000 task.ti: ffff8803cd31a000 [ 1317.268399] RIP: 0010:[<ffffffff84225f52>] [<ffffffff84225f52>] rds_ib_laddr_check+ 0x82/0x110 [ 1317.269670] RSP: 0000:ffff8803cd31bdf8 EFLAGS: 00010246 [ 1317.270230] RAX: 0000000000000000 RBX: ffff88020b0dd388 RCX: 0000000000000000 [ 1317.270230] RDX: ffffffff8439822e RSI: 00000000000c000a RDI: 0000000000000286 [ 1317.270230] RBP: ffff8803cd31be38 R08: 0000000000000000 R09: 0000000000000000 [ 1317.270230] R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 [ 1317.270230] R13: 0000000054086700 R14: 0000000000a25de0 R15: 0000000000000031 [ 1317.270230] FS: 00007ff40251d700(0000) GS:ffff88022e200000(0000) knlGS:000000000000 0000 [ 1317.270230] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 1317.270230] CR2: 0000000000000974 CR3: 00000003cd478000 CR4: 00000000000006e0 [ 1317.270230] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1317.270230] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000090602 [ 1317.270230] Stack: [ 1317.270230] 0000000054086700 5408670000a25de0 5408670000000002 0000000000000000 [ 1317.270230] ffffffff84223542 00000000ea54c767 0000000000000000 ffffffff86d26160 [ 1317.270230] ffff8803cd31be68 ffffffff84223556 ffff8803cd31beb8 ffff8800c6765280 [ 1317.270230] Call Trace: [ 1317.270230] [<ffffffff84223542>] ? rds_trans_get_preferred+0x42/0xa0 [ 1317.270230] [<ffffffff84223556>] rds_trans_get_preferred+0x56/0xa0 [ 1317.270230] [<ffffffff8421c9c3>] rds_bind+0x73/0xf0 [ 1317.270230] [<ffffffff83e4ce62>] SYSC_bind+0x92/0xf0 [ 1317.270230] [<ffffffff812493f8>] ? context_tracking_user_exit+0xb8/0x1d0 [ 1317.270230] [<ffffffff8119313d>] ? trace_hardirqs_on+0xd/0x10 [ 1317.270230] [<ffffffff8107a852>] ? syscall_trace_enter+0x32/0x290 [ 1317.270230] [<ffffffff83e4cece>] SyS_bind+0xe/0x10 [ 1317.270230] [<ffffffff843a6ad0>] tracesys+0xdd/0xe2 [ 1317.270230] Code: 00 8b 45 cc 48 8d 75 d0 48 c7 45 d8 00 00 00 00 66 c7 45 d0 02 00 89 45 d4 48 89 df e8 78 49 76 ff 41 89 c4 85 c0 75 0c 48 8b 03 <80> b8 74 09 00 00 01 7 4 06 41 bc 9d ff ff ff f6 05 2a b6 c2 02 [ 1317.270230] RIP [<ffffffff84225f52>] rds_ib_laddr_check+0x82/0x110 [ 1317.270230] RSP <ffff8803cd31bdf8> [ 1317.270230] CR2: 0000000000000974 Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> diff --git a/net/rds/ib.c b/net/rds/ib.c index b4c8b00..ba2dffe 100644 --- a/net/rds/ib.c +++ b/net/rds/ib.c @@ -338,7 +338,8 @@ static int rds_ib_laddr_check(__be32 addr) ret = rdma_bind_addr(cm_id, (struct sockaddr *)&sin); /* due to this, we will claim to support iWARP devices unless we check node_type. */ - if (ret || cm_id->device->node_type != RDMA_NODE_IB_CA) + if (ret || !cm_id->device || + cm_id->device->node_type != RDMA_NODE_IB_CA) ret = -EADDRNOTAVAIL; rdsdebug("addr %pI4 ret %d node type %d\n",