From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:49202) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SQE9f-0006sw-CN for qemu-devel@nongnu.org; Fri, 04 May 2012 04:46:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SQE9a-0007KN-4Q for qemu-devel@nongnu.org; Fri, 04 May 2012 04:46:22 -0400 Received: from mail-pz0-f44.google.com ([209.85.210.44]:52841) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SQE9Z-0007F2-S3 for qemu-devel@nongnu.org; Fri, 04 May 2012 04:46:18 -0400 Received: by mail-pz0-f44.google.com with SMTP id x6so2969373dac.31 for ; Fri, 04 May 2012 01:46:16 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Fri, 4 May 2012 10:45:43 +0200 Message-Id: <1336121154-26517-4-git-send-email-pbonzini@redhat.com> In-Reply-To: <1336121154-26517-1-git-send-email-pbonzini@redhat.com> References: <1336121154-26517-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 03/14] scsi: fix refcounting for reads List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Recently introduced FUA support also gave us a use-after-free of the BlockAcctCookie within a SCSIDiskReq, due to unbalanced reference counting. The patch fixes this by making scsi_do_read look like a combination of scsi_*_complete + scsi_*_data. It does both a ref (like scsi_read_data) and an unref (like scsi_flush_complete). Reported-by: David Gibson Signed-off-by: Paolo Bonzini --- hw/scsi-disk.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c index a029ab6..eca00a6 100644 --- a/hw/scsi-disk.c +++ b/hw/scsi-disk.c @@ -296,6 +296,13 @@ static void scsi_do_read(void *opaque, int ret) } } + if (r->req.io_canceled) { + return; + } + + /* The request is used as the AIO opaque value, so add a ref. */ + scsi_req_ref(&r->req); + if (r->req.sg) { dma_acct_start(s->qdev.conf.bs, &r->acct, r->req.sg, BDRV_ACCT_READ); r->req.resid -= r->req.sg->size; -- 1.7.9.3