From c4ffa69bdec932cf674d92355967ce2876296893 Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Tue, 6 Aug 2013 13:17:01 +0200 Subject: [PATCH 08/28] qemu-option: Fix qemu_opts_set_defaults() for corner cases RH-Author: Markus Armbruster Message-id: <1375795025-28674-3-git-send-email-armbru@redhat.com> Patchwork-id: 52990 O-Subject: [PATCH 7.0 qemu-kvm 2/6] qemu-option: Fix qemu_opts_set_defaults() for corner cases Bugzilla: 980782 RH-Acked-by: Laszlo Ersek RH-Acked-by: Michal Novotny RH-Acked-by: Orit Wasserman Commit 4f6dd9a changed the initialization of opts in opts_parse() to this: if (defaults) { if (!id && !QTAILQ_EMPTY(&list->head)) { opts = qemu_opts_find(list, NULL); } else { opts = qemu_opts_create(list, id, 0); } } else { opts = qemu_opts_create(list, id, 1); } Same as before for !defaults. If defaults is true, and params has no ID, and options exist, we use the first assignment. It sets opts to null if all options have an ID. opts_parse() then returns null. qemu_opts_set_defaults() asserts the value is non-null. It's the only caller that passes true for defaults. To reproduce, try "-M xenpv -machine id=foo" (yes, "id=foo" is silly, but it shouldn't crash). I believe the function attempts to do the following: If options don't yet exist, create new options Else, if defaults, modify the existing options Else, if list->merge_lists, modify the existing options Else, fail A straightforward call of qemu_opts_create() does exactly that. Cc: Jan Kiszka Signed-off-by: Markus Armbruster Message-id: 1372943363-24081-3-git-send-email-armbru@redhat.com Signed-off-by: Anthony Liguori (cherry picked from commit 6d4cd408686f5ae60b2b3b94b79f48ddedc2f39d) The upstream commit message's claim that a "straightforward call of qemu_opts_create() does exactly that" is wrong. When !list->merge_lists, and the option string doesn't contain id=, and options without ID exist, then we don't actually modify the existing options, we create new ones. Not reachable, because we never pass lists with !list->merge_lists to qemu_opts_set_defaults(). Patch adding a suitable assertion pending upstream. --- util/qemu-option.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) Signed-off-by: Miroslav Rezanina --- util/qemu-option.c | 10 +--------- 1 files changed, 1 insertions(+), 9 deletions(-) diff --git a/util/qemu-option.c b/util/qemu-option.c index b6d2ac0..bdfbdb4 100644 --- a/util/qemu-option.c +++ b/util/qemu-option.c @@ -944,15 +944,7 @@ static QemuOpts *opts_parse(QemuOptsList *list, const char *params, get_opt_value(value, sizeof(value), p+4); id = value; } - if (defaults) { - if (!id && !QTAILQ_EMPTY(&list->head)) { - opts = qemu_opts_find(list, NULL); - } else { - opts = qemu_opts_create(list, id, 0, &local_err); - } - } else { - opts = qemu_opts_create(list, id, 1, &local_err); - } + opts = qemu_opts_create(list, id, !defaults, &local_err); if (opts == NULL) { if (error_is_set(&local_err)) { qerror_report_err(local_err); -- 1.7.1