On Thu, Apr 29, 2021 at 11:05 AM Gioh Kim [off-list ref] wrote:

On Thu, Apr 29, 2021 at 10:58 AM Dan Carpenter [off-list ref] wrote:

quoted

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   593ef1658ecf61d3619885bdbbcfffa3d1417891
commit: fa607fcb87f6e3dca38b9984c4ccde3e36a43721 [13667/14048] block/rnbd-clt: Support polling mode for IO latency optimization
config: x86_64-randconfig-m031-20210420 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>
Reported-by: Dan Carpenter <redacted>

smatch warnings:
drivers/infiniband/ulp/rtrs/rtrs-clt.c:2922 rtrs_clt_rdma_cq_direct() error: uninitialized symbol 'cnt'.

vim +/cnt +2922 drivers/infiniband/ulp/rtrs/rtrs-clt.c

fa607fcb87f6e3 Gioh Kim  2021-04-19  2901  int rtrs_clt_rdma_cq_direct(struct rtrs_clt *clt, unsigned int index)
fa607fcb87f6e3 Gioh Kim  2021-04-19  2902  {
fa607fcb87f6e3 Gioh Kim  2021-04-19  2903       int cnt;
fa607fcb87f6e3 Gioh Kim  2021-04-19  2904       struct rtrs_con *con;
fa607fcb87f6e3 Gioh Kim  2021-04-19  2905       struct rtrs_clt_sess *sess;
fa607fcb87f6e3 Gioh Kim  2021-04-19  2906       struct path_it it;
fa607fcb87f6e3 Gioh Kim  2021-04-19  2907
fa607fcb87f6e3 Gioh Kim  2021-04-19  2908       rcu_read_lock();
fa607fcb87f6e3 Gioh Kim  2021-04-19  2909       for (path_it_init(&it, clt);
fa607fcb87f6e3 Gioh Kim  2021-04-19  2910            (sess = it.next_path(&it)) && it.i < it.clt->paths_num; it.i++) {
fa607fcb87f6e3 Gioh Kim  2021-04-19  2911               if (READ_ONCE(sess->state) != RTRS_CLT_CONNECTED)
fa607fcb87f6e3 Gioh Kim  2021-04-19  2912                       continue;

What if no sessions are connected?  So we dont enter the loop or we
hit continue every time?

Hi Dan,

I just finished a internal process for the fix of that issue.
In short, I would like to initialize cnt with -1.
So rtrs_clt_rdma_cq_direct will return -1 if there is no session.
And the block layer will not call rtrs_clt_rdma_cq_direct again
because the return value is negative.

I am going to send the patch today with the tags above.
Thank you very much.

Hi Dan,

FYI, I just sent a patch including the tags.

quoted

fa607fcb87f6e3 Gioh Kim  2021-04-19  2913
fa607fcb87f6e3 Gioh Kim  2021-04-19  2914               con = sess->s.con[index + 1];
fa607fcb87f6e3 Gioh Kim  2021-04-19  2915               cnt = ib_process_cq_direct(con->cq, -1);
fa607fcb87f6e3 Gioh Kim  2021-04-19  2916               if (cnt)
fa607fcb87f6e3 Gioh Kim  2021-04-19  2917                       break;
fa607fcb87f6e3 Gioh Kim  2021-04-19  2918       }
fa607fcb87f6e3 Gioh Kim  2021-04-19  2919       path_it_deinit(&it);
fa607fcb87f6e3 Gioh Kim  2021-04-19  2920       rcu_read_unlock();
fa607fcb87f6e3 Gioh Kim  2021-04-19  2921
fa607fcb87f6e3 Gioh Kim  2021-04-19 @2922       return cnt;
fa607fcb87f6e3 Gioh Kim  2021-04-19  2923  }

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