Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block patches for 2.1.0-rc0

# gpg: Signature made Fri 27 Jun 2014 19:50:32 BST using RSA key ID C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"

* remotes/kevin/tags/for-upstream: (47 commits)
  iotests: Fix 083 for out-of-tree builds
  iotests: Drop Python version from 065's Shebang
  iotests: Use $PYTHON for Python scripts
  iotests: Source common.env
  configure: Enable out-of-tree iotests
  iotests: Allow out-of-tree run
  block.c: Don't return success for bdrv_append_temp_snapshot() failure
  qemu-iotests: Add TestRepairQuorum to 041 to test drive-mirror node-name mode.
  block: Add replaces argument to drive-mirror
  blockjob: Fix recent BLOCK_JOB_ERROR regression
  blockjob: Fix recent BLOCK_JOB_READY regression
  virtio-blk: Rename complete_request_early to complete_request_vring
  virtio-blk: Unify {non-,}dataplane's request handlings
  virtio-blk: Schedule BH in the right context
  virtio-blk: Export request handling functions to dataplane
  virtio-blk: Make request completion function virtual
  block: acquire AioContext in qmp_query_blockstats()
  block: make bdrv_query_stats() static
  virtio-blk: Fix and clean up the in_sg and out_sg check
  virtio-blk: Fill in VirtIOBlockReq.out in dataplane code
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 10 insertions, 1 deletions

diff --git a/util/qemu-option.c b/util/qemu-option.c
index 43de3ad..6dc27ce 100644
--- a/util/qemu-option.c
+++ b/util/qemu-option.c
@@ -1111,6 +1111,7 @@ QemuOptsList *qemu_opts_append(QemuOptsList *dst,
     size_t num_opts, num_dst_opts;
     QemuOptDesc *desc;
     bool need_init = false;
+    bool need_head_update;
 
     if (!list) {
         return dst;
@@ -1121,6 +1122,12 @@ QemuOptsList *qemu_opts_append(QemuOptsList *dst,
      */
     if (!dst) {
         need_init = true;
+        need_head_update = true;
+    } else {
+        /* Moreover, even if dst is not NULL, the realloc may move it to a
+         * different address in which case we may get a stale tail pointer
+         * in dst->head. */
+        need_head_update = QTAILQ_EMPTY(&dst->head);
     }
 
     num_opts = count_opts_list(dst);
@@ -1131,9 +1138,11 @@ QemuOptsList *qemu_opts_append(QemuOptsList *dst,
     if (need_init) {
         dst->name = NULL;
         dst->implied_opt_name = NULL;
-        QTAILQ_INIT(&dst->head);
         dst->merge_lists = false;
     }
+    if (need_head_update) {
+        QTAILQ_INIT(&dst->head);
+    }
     dst->desc[num_dst_opts].name = NULL;
 
     /* append list->desc to dst->desc */