From: Kinglong Mee kinglongmee@gmail.com
[ Upstream commit 11270e7ca268e8d61b5d9e5c3a54bd1550642c9c ]
When a rdma server returns a fault format reply, nfs v3 client may treats it as a bcall when bc service is not exist.
The debug message at rpcrdma_bc_receive_call are,
[56579.837169] RPC: rpcrdma_bc_receive_call: callback XID 00000001, length=20 [56579.837174] RPC: rpcrdma_bc_receive_call: 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04
After that, rpcrdma_bc_receive_call will meets NULL pointer as,
[ 226.057890] BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8 ... [ 226.058704] RIP: 0010:_raw_spin_lock+0xc/0x20 ... [ 226.059732] Call Trace: [ 226.059878] rpcrdma_bc_receive_call+0x138/0x327 [rpcrdma] [ 226.060011] __ib_process_cq+0x89/0x170 [ib_core] [ 226.060092] ib_cq_poll_work+0x26/0x80 [ib_core] [ 226.060257] process_one_work+0x1a7/0x360 [ 226.060367] ? create_worker+0x1a0/0x1a0 [ 226.060440] worker_thread+0x30/0x390 [ 226.060500] ? create_worker+0x1a0/0x1a0 [ 226.060574] kthread+0x116/0x130 [ 226.060661] ? kthread_flush_work_fn+0x10/0x10 [ 226.060724] ret_from_fork+0x35/0x40 ...
Signed-off-by: Kinglong Mee kinglongmee@gmail.com Reviewed-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Anna Schumaker Anna.Schumaker@Netapp.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/sunrpc/xprtrdma/rpc_rdma.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index c091417bd799..60aaed9457e4 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -1042,6 +1042,7 @@ static bool rpcrdma_is_bcall(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep) #if defined(CONFIG_SUNRPC_BACKCHANNEL) { + struct rpc_xprt *xprt = &r_xprt->rx_xprt; struct xdr_stream *xdr = &rep->rr_stream; __be32 *p;
@@ -1065,6 +1066,10 @@ rpcrdma_is_bcall(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep) if (*p != cpu_to_be32(RPC_CALL)) return false;
+ /* No bc service. */ + if (xprt->bc_serv == NULL) + return false; + /* Now that we are sure this is a backchannel call, * advance to the RPC header. */