diff --git a/kmod/src/Makefile.kernelcompat b/kmod/src/Makefile.kernelcompat
index 8e484301..6efcb1a6 100644
--- a/kmod/src/Makefile.kernelcompat
+++ b/kmod/src/Makefile.kernelcompat
@@ -572,6 +572,14 @@ ifneq (,$(shell grep -s 'int set_blocksize.struct file' include/linux/blkdev.h))
 ccflags-y += -DKC_BLKDEV_SET_BLOCKSIZE_FILE
 endif
 
+#
+# v5.1-rc3-29-gaa30f47cf666
+#
+# struct kobj_type now has member `default_groups`
+ifneq (,$(shell grep 'const struct attribute_group ..default_groups;' include/linux/kobject.h))
+ccflags-y += -DKC_KOBJECT_DEFAULT_GROUPS
+endif
+
 #
 # v6.15-13744-g41cb08555c41
 #
diff --git a/kmod/src/counters.c b/kmod/src/counters.c
index 5578ae26..9ba5b1a7 100644
--- a/kmod/src/counters.c
+++ b/kmod/src/counters.c
@@ -34,6 +34,17 @@ static struct attribute scoutfs_counter_attrs[] = {
 #define NR_ATTRS ARRAY_SIZE(scoutfs_counter_attrs)
 static struct attribute *scoutfs_counter_attr_ptrs[NR_ATTRS + 1];
 
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+static struct attribute_group scoutfs_counter_attr_group = {
+	.attrs = scoutfs_counter_attr_ptrs,
+};
+
+static const struct attribute_group *scoutfs_counter_attr_groups[] = {
+	&scoutfs_counter_attr_group,
+	NULL,
+};
+#endif
+
 static ssize_t scoutfs_counter_attr_show(struct kobject *kobj,
 				         struct attribute *attr, char *buf)
 {
@@ -45,7 +56,6 @@ static ssize_t scoutfs_counter_attr_show(struct kobject *kobj,
 	counters = container_of(kobj, struct scoutfs_counters, kobj);
 	index = attr - scoutfs_counter_attrs;
 	pcpu = &counters->FIRST_COUNTER + index;
-
 	return snprintf(buf, PAGE_SIZE, "%lld\n", percpu_counter_sum(pcpu));
 }
 
@@ -63,7 +73,7 @@ static const struct sysfs_ops scoutfs_counter_attr_ops = {
 };
 
 static struct kobj_type scoutfs_counters_ktype = {
-	.default_attrs  = scoutfs_counter_attr_ptrs,
+	.KC_KOBJ_DEFAULT_OP = KC_KOBJ_DEFAULT_PICK(scoutfs_counter_attr_groups, scoutfs_counter_attr_ptrs),
 	.sysfs_ops      = &scoutfs_counter_attr_ops,
 	.release        = scoutfs_counters_kobj_release,
 };
diff --git a/kmod/src/fence.c b/kmod/src/fence.c
index c63f27b4..67e693d0 100644
--- a/kmod/src/fence.c
+++ b/kmod/src/fence.c
@@ -217,6 +217,9 @@ static struct attribute *fence_attrs[] = {
 	SCOUTFS_ATTR_PTR(rid),
 	NULL,
 };
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+ATTRIBUTE_GROUPS(fence);
+#endif
 
 #define FENCE_TIMEOUT_MS (MSEC_PER_SEC * 30)
 
@@ -255,7 +258,8 @@ int scoutfs_fence_start(struct super_block *sb, u64 rid, __be32 ipv4_addr, int r
 	fence->rid = rid;
 
 	ret = scoutfs_sysfs_create_attrs_parent(sb, &fi->kset->kobj,
-						&fence->ssa, fence_attrs,
+						&fence->ssa,
+						KC_KOBJ_DEFAULT(fence),
 						"%016llx", rid);
 	if (ret < 0) {
 		kfree(fence);
diff --git a/kmod/src/kernelcompat.h b/kmod/src/kernelcompat.h
index e1a439f8..103fc5d8 100644
--- a/kmod/src/kernelcompat.h
+++ b/kmod/src/kernelcompat.h
@@ -639,6 +639,16 @@ static inline long inode_get_atime_nsec(const struct inode *inode)
 #define kc__assign_str(a, b) __assign_str(a)
 #endif
 
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+#define KC_KOBJ_DEFAULT_OP default_groups
+#define KC_KOBJ_DEFAULT(name) (name##_groups)
+#define KC_KOBJ_DEFAULT_PICK(group, attrs) (group)
+#else
+#define KC_KOBJ_DEFAULT_OP default_attrs
+#define KC_KOBJ_DEFAULT(name) (name##_attrs)
+#define KC_KOBJ_DEFAULT_PICK(group, attrs) (attrs)
+#endif
+
 #ifndef KC_TIMER_CONTAINER_OF
 #define timer_container_of(var, callback_timer, timer_fieldname) \
 	from_timer(var, callback_timer, timer_fieldname)
diff --git a/kmod/src/options.c b/kmod/src/options.c
index b7565d76..6812a7db 100644
--- a/kmod/src/options.c
+++ b/kmod/src/options.c
@@ -752,13 +752,18 @@ static struct attribute *options_attrs[] = {
 	SCOUTFS_ATTR_PTR(quorum_slot_nr),
 	NULL,
 };
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+ATTRIBUTE_GROUPS(options);
+#endif
 
 int scoutfs_options_setup(struct super_block *sb)
 {
 	DECLARE_OPTIONS_INFO(sb, optinf);
 	int ret;
 
-	ret = scoutfs_sysfs_create_attrs(sb, &optinf->sysfs_attrs, options_attrs, "mount_options");
+	ret = scoutfs_sysfs_create_attrs(sb, &optinf->sysfs_attrs,
+					 KC_KOBJ_DEFAULT_PICK(options_groups, options_attrs),
+					 "mount_options");
 	if (ret < 0)
 		scoutfs_options_destroy(sb);
 	return ret;
diff --git a/kmod/src/quorum.c b/kmod/src/quorum.c
index abb331cc..5541465d 100644
--- a/kmod/src/quorum.c
+++ b/kmod/src/quorum.c
@@ -1192,6 +1192,9 @@ static struct attribute *quorum_attrs[] = {
 	SCOUTFS_ATTR_PTR(is_leader),
 	NULL,
 };
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+ATTRIBUTE_GROUPS(quorum);
+#endif
 
 static inline bool valid_ipv4_unicast(__be32 addr)
 {
@@ -1352,7 +1355,7 @@ int scoutfs_quorum_setup(struct super_block *sb)
 	if (ret < 0)
 		goto out;
 
-	ret = scoutfs_sysfs_create_attrs(sb, &qinf->ssa, quorum_attrs,
+	ret = scoutfs_sysfs_create_attrs(sb, &qinf->ssa, KC_KOBJ_DEFAULT(quorum),
 					 "quorum");
 	if (ret < 0)
 		goto out;
diff --git a/kmod/src/srch.c b/kmod/src/srch.c
index d6ffc10f..efd72061 100644
--- a/kmod/src/srch.c
+++ b/kmod/src/srch.c
@@ -2350,6 +2350,9 @@ static struct attribute *srch_attrs[] = {
 	SCOUTFS_ATTR_PTR(compact_delay_ms),
 	NULL,
 };
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+ATTRIBUTE_GROUPS(srch);
+#endif
 
 void scoutfs_srch_destroy(struct super_block *sb)
 {
@@ -2391,7 +2394,8 @@ int scoutfs_srch_setup(struct super_block *sb)
 
 	sbi->srch_info = srinf;
 
-	ret = scoutfs_sysfs_create_attrs(sb, &srinf->ssa, srch_attrs, "srch");
+	ret = scoutfs_sysfs_create_attrs(sb, &srinf->ssa, KC_KOBJ_DEFAULT(srch),
+					 "srch");
 	if (ret < 0)
 		goto out;
 
diff --git a/kmod/src/sysfs.c b/kmod/src/sysfs.c
index b3c7ddbf..3b7e176f 100644
--- a/kmod/src/sysfs.c
+++ b/kmod/src/sysfs.c
@@ -103,12 +103,11 @@ static ssize_t attr_funcs_show(struct kobject *kobj, struct attribute *attr,
 	};								\
 									\
 	static struct kobj_type _name##_ktype = {			\
-		.default_attrs  = _name##_attrs,			\
+		.KC_KOBJ_DEFAULT_OP = KC_KOBJ_DEFAULT(_name),		\
 		.sysfs_ops      = &_name##_sysfs_ops,			\
 		.release        = _name##_release,			\
 	};
 
-
 static struct attribute *sb_id_attrs[] = {
 	&data_device_maj_min_attr_funcs.attr,
 	&format_version_attr_funcs.attr,
@@ -116,6 +115,9 @@ static struct attribute *sb_id_attrs[] = {
 	&rid_attr_funcs.attr,
 	NULL,
 };
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+ATTRIBUTE_GROUPS(sb_id);
+#endif
 KTYPE(sb_id);
 
 struct kobject *scoutfs_sysfs_sb_dir(struct super_block *sb)
@@ -155,7 +157,12 @@ void scoutfs_sysfs_init_attrs(struct super_block *sb,
 int scoutfs_sysfs_create_attrs_parent(struct super_block *sb,
 				      struct kobject *parent,
 				      struct scoutfs_sysfs_attrs *ssa,
-				      struct attribute **attrs, char *fmt, ...)
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+				      const struct attribute_group **groups,
+#else
+				      struct attribute **attrs,
+#endif
+				      char *fmt, ...)
 {
 	va_list args;
 	size_t name_len;
@@ -168,7 +175,11 @@ int scoutfs_sysfs_create_attrs_parent(struct super_block *sb,
 
 	ssa->sb = sb;
 	init_completion(&ssa->comp);
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+	ssa->ktype.default_groups = groups;
+#else
 	ssa->ktype.default_attrs = attrs;
+#endif
 	ssa->ktype.sysfs_ops = &kobj_sysfs_ops;
 	ssa->ktype.release = scoutfs_sysfs_release;
 
diff --git a/kmod/src/sysfs.h b/kmod/src/sysfs.h
index 70b85af8..177e98f7 100644
--- a/kmod/src/sysfs.h
+++ b/kmod/src/sysfs.h
@@ -39,10 +39,15 @@ void scoutfs_sysfs_init_attrs(struct super_block *sb,
 int scoutfs_sysfs_create_attrs_parent(struct super_block *sb,
 				      struct kobject *parent,
 				      struct scoutfs_sysfs_attrs *ssa,
-				      struct attribute **attrs, char *fmt, ...);
-#define scoutfs_sysfs_create_attrs(sb, ssa, attrs, fmt, args...)	\
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+				      const struct attribute_group **groups,
+#else
+				      struct attribute **attrs,
+#endif
+				      char *fmt, ...);
+#define scoutfs_sysfs_create_attrs(sb, ssa, group_or_attrs, fmt, args...)	\
 	scoutfs_sysfs_create_attrs_parent(sb, scoutfs_sysfs_sb_dir(sb),	\
-					  ssa, attrs, fmt, ##args)
+					  ssa, group_or_attrs, fmt, ##args)
 
 void scoutfs_sysfs_destroy_attrs(struct super_block *sb,
 				 struct scoutfs_sysfs_attrs *ssa);
diff --git a/kmod/src/volopt.c b/kmod/src/volopt.c
index 303d94b0..b87e4ac5 100644
--- a/kmod/src/volopt.c
+++ b/kmod/src/volopt.c
@@ -52,6 +52,15 @@ static struct volopt_nr_name {
 /* initialized by setup, pointer array is null terminated */
 static struct kobj_attribute volopt_attrs[ARRAY_SIZE(volopt_table)];
 static struct attribute *volopt_attr_ptrs[ARRAY_SIZE(volopt_table) + 1];
+#ifdef KC_KOBJECT_DEFAULT_GROUPS
+static const struct attribute_group volopt_group = {
+	.attrs = volopt_attr_ptrs,
+};
+static const struct attribute_group *volopt_groups[] = {
+	&volopt_group,
+	NULL,
+};
+#endif
 
 static void get_opt_data(struct kobj_attribute *attr, struct scoutfs_volume_options *volopt,
 			 u64 *bit, __le64 **opt)
@@ -164,7 +173,9 @@ int scoutfs_volopt_setup(struct super_block *sb)
 	BUILD_BUG_ON(ARRAY_SIZE(volopt_table) != ARRAY_SIZE(volopt_attr_ptrs) - 1);
 	volopt_attr_ptrs[i] = NULL;
 
-	ret = scoutfs_sysfs_create_attrs(sb, &vinf->ssa, volopt_attr_ptrs, "volume_options");
+	ret = scoutfs_sysfs_create_attrs(sb, &vinf->ssa,
+					 KC_KOBJ_DEFAULT_PICK(volopt_groups, volopt_attr_ptrs),
+					 "volume_options");
 	if (ret < 0)
 		goto out;