Need some pointers to debug a KASAN splat in NVMe over Fabrics with rdma-rxe

[jthumshirn@suse.de (Johannes Thumshirn)]

On 03/08/2017 04:35 PM, Johannes Thumshirn wrote:
> Hi Moni et al.,
> 
> I'm getting a KASAN stack-out-of-bounds in rxe_post_send+0xdfe/0x1830
> [rdma_rxe] at addr ffff8800187072e8 with v4.11-rc1
> 
> rxe_post_send+0xdfe is the following (note: the pr_err was inserted by
> me to aid debugging).

Quick follow up to my last mail

Slamming in a:
@@ -753,9 +757,18 @@ static int init_send_wqe(struct rxe_qp *qp, struct
ib_send_wr *ibwr,
                memcpy(wqe->dma.sge, ibwr->sg_list,
                       num_sge * sizeof(struct ib_sge));

-       wqe->iova               = (mask & WR_ATOMIC_MASK) ?
-                                       atomic_wr(ibwr)->remote_addr :
-                                       rdma_wr(ibwr)->remote_addr;
+
+       if (ibwr->opcode == IB_WR_RDMA_WRITE ||
+           ibwr->opcode == IB_WR_RDMA_WRITE_WITH_IMM ||
+           ibwr->opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
+           ibwr->opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
+               wqe->iova = (mask & WR_ATOMIC_MASK) ?
+                       atomic_wr(ibwr)->remote_addr :
+                       rdma_wr(ibwr)->remote_addr;
+
        wqe->mask               = mask;
        wqe->dma.length         = length;
        wqe->dma.resid          = length;


Gives me
[    4.286632] rdma_rxe: qp#17 moved to error state
[ ...hang... ]
[   64.847464] nvme nvme0: Connect command failed, error wo/DNR bit: 7
[   64.859829]
==================================================================
[   64.861048] BUG: KASAN: stack-out-of-bounds in
rxe_post_send+0x12f3/0x1880 [rdma_rxe] at addr ffff88001f787838

Which translates to:
(gdb) list *(rxe_post_send+0x12f3)
0x1e133 is in rxe_post_send (drivers/infiniband/sw/rxe/rxe_verbs.c:685).
680                     switch (wr->opcode) {
681                     case IB_WR_RDMA_WRITE_WITH_IMM:
682                             wr->ex.imm_data = ibwr->ex.imm_data;
683                     case IB_WR_RDMA_READ:
684                     case IB_WR_RDMA_WRITE:
685                             wr->wr.rdma.remote_addr =
rdma_wr(ibwr)->remote_addr;
686                             wr->wr.rdma.rkey        =
rdma_wr(ibwr)->rkey;
687                             break;
688                     case IB_WR_SEND_WITH_IMM:
689                             wr->ex.imm_data = ibwr->ex.imm_data;


-- 
Johannes Thumshirn                                          Storage
jthumshirn at suse.de                                +49 911 74053 689
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