RDMA/rxe: Fix a race condition in rxe_requester()

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The rxe driver works as follows:
* The send queue, receive queue and completion queues are implemented as
  circular buffers.
* ib_post_send() and ib_post_recv() calls are serialized through a spinlock.
* Removing elements from various queues happens from tasklet
  context. Tasklets are guaranteed to run on at most one CPU. This serializes
  access to these queues. See also rxe_completer(), rxe_requester() and
  rxe_responder().
* rxe_completer() processes the skbs queued onto qp->resp_pkts.
* rxe_requester() handles the send queue (qp->sq.queue).
* rxe_responder() processes the skbs queued onto qp->req_pkts.

Since rxe_drain_req_pkts() processes qp->req_pkts, calling
rxe_drain_req_pkts() from rxe_requester() is racy. Hence this patch.

Reported-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: stable@vger.kernel.org
Signed-off-by: Doug Ledford <dledford@redhat.com>

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This commit is contained in:

Bart Van Assche 2018-01-12 15:11:58 -08:00 • committed by Doug Ledford

parent 37cb11acf1

commit 65567e4121

3 changed files with 2 additions and 10 deletions

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1

drivers/infiniband/sw/rxe/rxe_loc.h

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9

drivers/infiniband/sw/rxe/rxe_req.c

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2

drivers/infiniband/sw/rxe/rxe_resp.c

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