If the stars are in the right position and you're building with VBox >= 4.2.0 it will happen that compiler thinks an array allocated on the stack may be unbound: In file included from vbox/vbox_V4_2.c:13:0: vbox/vbox_tmpl.c: In function '_virtualboxCreateMachine': vbox/vbox_tmpl.c:2811:1: error: stack usage might be unbounded [-Werror=stack-usage=] _virtualboxCreateMachine(vboxGlobalData *data, virDomainDefPtr def, IMachine **machine, char *uuidstr ATTRIBUTE_UNUSED) ^ Well, given how the variable is declared, I had some hard time seeing it is actually bounded. Surprisingly compiler does not complain because of -Wframe-larger-than. This is because variable length arrays do not count into that warning. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/vbox/vbox_tmpl.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/src/vbox/vbox_tmpl.c b/src/vbox/vbox_tmpl.c index 0fbd5b3..7a8205d 100644 --- a/src/vbox/vbox_tmpl.c +++ b/src/vbox/vbox_tmpl.c @@ -2812,7 +2812,7 @@ _virtualboxCreateMachine(vboxGlobalData *data, virDomainDefPtr def, IMachine **m { vboxIID iid = VBOX_IID_INITIALIZER; PRUnichar *machineNameUtf16 = NULL; - nsresult rc; + nsresult rc = -1; VBOX_UTF8_TO_UTF16(def->name, &machineNameUtf16); vboxIIDFromUUID(&iid, def->uuid); @@ -2843,18 +2843,12 @@ _virtualboxCreateMachine(vboxGlobalData *data, virDomainDefPtr def, IMachine **m override, machine); #else /* VBOX_API_VERSION >= 4002000 */ - const char *flagsUUIDPrefix = "UUID="; - const char *flagsForceOverwrite = "forceOverwrite=0"; - const char *flagsSeparator = ","; - char createFlags[strlen(flagsUUIDPrefix) + VIR_UUID_STRING_BUFLEN + strlen(flagsSeparator) + strlen(flagsForceOverwrite) + 1]; + char *createFlags = NULL; PRUnichar *createFlagsUtf16 = NULL; - snprintf(createFlags, sizeof(createFlags), "%s%s%s%s", - flagsUUIDPrefix, - uuidstr, - flagsSeparator, - flagsForceOverwrite - ); + if (virAsprintf(&createFlags, + "UUID=%s,forceOverwrite=0", uuidstr) < 0) + goto cleanup; VBOX_UTF8_TO_UTF16(createFlags, &createFlagsUtf16); rc = data->vboxObj->vtbl->CreateMachine(data->vboxObj, NULL, @@ -2864,6 +2858,8 @@ _virtualboxCreateMachine(vboxGlobalData *data, virDomainDefPtr def, IMachine **m nsnull, createFlagsUtf16, machine); + cleanup: + VIR_FREE(createFlags); #endif /* VBOX_API_VERSION >= 4002000 */ } VBOX_UTF16_FREE(machineNameUtf16); -- 2.4.10