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[PULL,1/2] 9pfs: fix multiple flush for same request

Message ID 1491322410-24532-2-git-send-email-groug@kaod.org (mailing list archive)
State New, archived
Headers show

Commit Message

Greg Kurz April 4, 2017, 4:13 p.m. UTC 
If a client tries to flush the same outstanding request several times, only
the first flush completes. Subsequent ones keep waiting for the request
completion in v9fs_flush() and, therefore, leak a PDU. This will cause QEMU
to hang when draining active PDUs the next time the device is reset.

Let have each flush request wake up the next one if any. The last waiter
frees the cancelled PDU.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 hw/9pfs/9p.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 48babce836b6..ef47a0a5ad6f 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -2387,8 +2387,10 @@  static void coroutine_fn v9fs_flush(void *opaque)
          * Wait for pdu to complete.
          */
         qemu_co_queue_wait(&cancel_pdu->complete, NULL);
-        cancel_pdu->cancelled = 0;
-        pdu_free(cancel_pdu);
+        if (!qemu_co_queue_next(&cancel_pdu->complete)) {
+            cancel_pdu->cancelled = 0;
+            pdu_free(cancel_pdu);
+        }
     }
     pdu_complete(pdu, 7);
 }