Re: [PATCH for-rc v3 0/6] RDMA/rxe: Various bug fixes.

Bart Van Assche
2021-09-10T22:07:56Z

On 9/10/21 2:47 PM, Bob Pearson wrote:
> OK I checked out the kernel with the SHA number above and applied the patch series
> and rebuilt and reinstalled the kernel. I checked out v36.0 of rdma-core and rebuilt
> that. rdma is version 5.9.0 but I doubt that will have any effect. My startup script
> is
>
> export LD_LIBRARY_PATH=/home/bob/src/rdma-core/build/lib/:/usr/local/lib:/usr/lib
>
>
>
> sudo ip link set dev enp0s3 mtu 8500
>
> sudo ip addr add dev enp0s3 fe80::0a00:27ff:fe94:8a69/64
>
> sudo rdma link add rxe0 type rxe netdev enp0s3
>
>
> I am running on a Virtualbox VM instance of Ubuntu 21.04 with 20 cores and 8GB of RAM.
>
> The test looks like
>
> sudo ./check -q srp/001
>
> srp/001 (Create and remove LUNs) [passed]
>
> runtime 1.174s ... 1.236s
>
> There were no issues.
>
> Any guesses what else to look at?

The test I ran is different. I did not run any of the ip link / ip addr /
rdma link commands since the blktests scripts already run the rdma link
command. The bug I reported in my previous email is reproducible and
triggers a VM halt.

Are we using the same kernel config? I attached my kernel config to my
previous email. The source code location of the crash address is as
follows:

(gdb) list *(rxe_completer+0x96d)
0x228d is in rxe_completer (drivers/infiniband/sw/rxe/rxe_comp.c:149).
144 */
145 wqe = queue_head(qp->sq.queue, QUEUE_TYPE_FROM_CLIENT);
146 *wqe_p = wqe;
147
148 /* no WQE or requester has not started it yet */
149 if (!wqe || wqe->state == wqe_state_posted)
150 return pkt ? COMPST_DONE : COMPST_EXIT;
151
152 /* WQE does not require an ack */
153 if (wqe->state == wqe_state_done)

The disassembly output is as follows:

drivers/infiniband/sw/rxe/rxe_comp.c:
149 if (!wqe || wqe->state == wqe_state_posted)
0x0000000000002277 <+2391>: test %r12,%r12
0x000000000000227a <+2394>: je 0x2379 <rxe_completer+2649>
0x0000000000002280 <+2400>: lea 0x94(%r12),%rdi
0x0000000000002288 <+2408>: call 0x228d <rxe_completer+2413>
0x000000000000228d <+2413>: mov 0x94(%r12),%eax
0x0000000000002295 <+2421>: test %eax,%eax
0x0000000000002297 <+2423>: je 0x237c <rxe_completer+2652>

So the instruction that triggers the crash is "mov 0x94(%r12),%eax".
Does consumer_addr() perhaps return an invalid address under certain
circumstances?

Thanks,

Bart.