Message ID | 20240223085653.1255438-5-zhao1.liu@linux.intel.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | Cleanup and fix @errp dereference | expand |
On 23/2/24 09:56, Zhao Liu wrote: > From: Zhao Liu <zhao1.liu@intel.com> > > As the comment in qapi/error, dereferencing @errp requires > ERRP_GUARD(): > > * = Why, when and how to use ERRP_GUARD() = > * > * Without ERRP_GUARD(), use of the @errp parameter is restricted: > * - It must not be dereferenced, because it may be null. > ... > * ERRP_GUARD() lifts these restrictions. > * > * To use ERRP_GUARD(), add it right at the beginning of the function. > * @errp can then be used without worrying about the argument being > * NULL or &error_fatal. > * > * Using it when it's not needed is safe, but please avoid cluttering > * the source with useless code. > > But in trng_prop_fault_event_set, @errp is dereferenced without > ERRP_GUARD(): > > visit_type_uint32(v, name, events, errp); > if (*errp) { > return; > } > > Currently, since trng_prop_fault_event_set() doesn't get the NULL @errp > parameter as a "set" method of object property, it hasn't triggered the > bug that dereferencing the NULL @errp. > > And since visit_type_uint32() returns bool, check the returned bool > directly instead of dereferencing @errp, then we needn't the add missing > ERRP_GUARD(). > > Suggested-by: Markus Armbruster <armbru@redhat.com> > Signed-off-by: Zhao Liu <zhao1.liu@intel.com> > --- > Suggested by credit: > Markus: Referred his explanation about ERRP_GUARD(). > --- > v2: > * Add the @errp dereference code in commit message to make review > easier. (Markus) > * Check the returned bool instead of dereferencing @errp. (Markus) > --- > hw/misc/xlnx-versal-trng.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
diff --git a/hw/misc/xlnx-versal-trng.c b/hw/misc/xlnx-versal-trng.c index b8111b8b6626..6495188dc748 100644 --- a/hw/misc/xlnx-versal-trng.c +++ b/hw/misc/xlnx-versal-trng.c @@ -644,8 +644,7 @@ static void trng_prop_fault_event_set(Object *obj, Visitor *v, Property *prop = opaque; uint32_t *events = object_field_prop_ptr(obj, prop); - visit_type_uint32(v, name, events, errp); - if (*errp) { + if (!visit_type_uint32(v, name, events, errp)) { return; }