From 18adde86ddc6dbef865a3d360bf8e15dce85756d Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Tue, 4 Apr 2017 18:06:01 +0200 Subject: [PATCH] 9pfs: fix multiple flush for same request 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 Reviewed-by: Eric Blake --- hw/9pfs/9p.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index 48babce836..ef47a0a5ad 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); }