In the Linux kernel, the following vulnerability has been resolved:

nvmet-rdma: fix response resource leak on queue teardown

When an nvme target with rdma transport is removed while I/Os are in
flight, a response can be posted but its send completion is never
delivered before the connection is torn down. As a result
nvmet_rdma_send_done() and nvmet_rdma_release_rsp() are never called for
the response, and this leaks the allocated RDMA read/write context and
request SGLs.

These leaks are recreated by running blktests nvme/061 with the rdma
transport and the siw driver. Kernel kmemleak feature reports them as
follows:

  unreferenced object 0xffff88812bc490c0 (size 32):
    comm "kworker/2:1H", pid 409, jiffies 4307744490
    backtrace (crc 89afd339):
      __kmalloc_noprof+0x5f9/0x890
      sgl_alloc_order+0x7b/0x380
      nvmet_req_alloc_sgls+0x290/0x4f0 [nvmet]
      nvmet_rdma_map_sgl_keyed+0x241/0x12e0 [nvmet_rdma]
      nvmet_rdma_handle_command+0x73e/0xb80 [nvmet_rdma]
      __ib_process_cq+0x149/0x4c0 [ib_core]
      ib_cq_poll_work+0x49/0x160 [ib_core]
      process_one_work+0x8b2/0x1640
      worker_thread+0x5fd/0xfe0
      kthread+0x367/0x460
      ret_from_fork+0x655/0x9d0
      ret_from_fork_asm+0x1a/0x30

  unreferenced object 0xffff88814bd05e80 (size 64):
    comm "kworker/3:1H", pid 148, jiffies 4295195428
    backtrace (crc e35510cb):
      __kmalloc_noprof+0x5f9/0x890
      rdma_rw_ctx_init+0x333/0x1fa0 [ib_core]
      nvmet_rdma_map_sgl_keyed+0x5c8/0x12e0 [nvmet_rdma]
      nvmet_rdma_handle_command+0x73e/0xb80 [nvmet_rdma]
      __ib_process_cq+0x149/0x4c0 [ib_core]
      ib_cq_poll_work+0x49/0x160 [ib_core]
      process_one_work+0x8b2/0x1640
      worker_thread+0x5fd/0xfe0
      kthread+0x367/0x460
      ret_from_fork+0x655/0x9d0
      ret_from_fork_asm+0x1a/0x30

To avoid the memory leaks, reclaim the memory of the in-flight responses
when the queue QP is torn down. Call nvmet_rdma_free_rsp_resources()
that frees up the RDMA read/write context and the request SGLs of such
responses.