--- uts/common/fs/zfs/arc.c
+++ uts/common/fs/zfs/arc.c
@@ -1138,6 +1138,7 @@
 	buf->b_efunc = NULL;
 	buf->b_private = NULL;
 	buf->b_next = NULL;
+	rw_init(&buf->b_lock, NULL, RW_DEFAULT, NULL);
 	hdr->b_buf = buf;
 	arc_get_data_buf(buf);
 	hdr->b_datacnt = 1;
@@ -1161,6 +1162,7 @@
 	buf->b_efunc = NULL;
 	buf->b_private = NULL;
 	buf->b_next = hdr->b_buf;
+	rw_init(&buf->b_lock, NULL, RW_DEFAULT, NULL);
 	hdr->b_buf = buf;
 	arc_get_data_buf(buf);
 	bcopy(from->b_data, buf->b_data, size);
@@ -1283,6 +1285,7 @@
 
 	/* clean up the buf */
 	buf->b_hdr = NULL;
+	rw_destroy(&buf->b_lock);
 	kmem_cache_free(buf_cache, buf);
 }
 
@@ -1332,8 +1335,10 @@
 			ASSERT(buf->b_hdr != NULL);
 			arc_buf_destroy(hdr->b_buf, FALSE, FALSE);
 			hdr->b_buf = buf->b_next;
+			rw_enter(&buf->b_lock, RW_WRITER);
 			buf->b_hdr = &arc_eviction_hdr;
 			buf->b_next = arc_eviction_list;
+			rw_exit(&buf->b_lock);
 			arc_eviction_list = buf;
 			mutex_exit(&arc_eviction_mtx);
 		} else {
@@ -1497,8 +1502,10 @@
 					arc_buf_destroy(buf,
 					    buf->b_data == stolen, FALSE);
 					ab->b_buf = buf->b_next;
+					rw_enter(&buf->b_lock, RW_WRITER);
 					buf->b_hdr = &arc_eviction_hdr;
 					buf->b_next = arc_eviction_list;
+					rw_exit(&buf->b_lock);
 					arc_eviction_list = buf;
 					mutex_exit(&arc_eviction_mtx);
 				} else {
@@ -1697,7 +1704,9 @@
 	while (arc_eviction_list != NULL) {
 		arc_buf_t *buf = arc_eviction_list;
 		arc_eviction_list = buf->b_next;
+		rw_enter(&buf->b_lock, RW_WRITER);
 		buf->b_hdr = NULL;
+		rw_exit(&buf->b_lock);
 		mutex_exit(&arc_eviction_mtx);
 
 		if (buf->b_efunc != NULL)
@@ -1705,6 +1714,7 @@
 
 		buf->b_efunc = NULL;
 		buf->b_private = NULL;
+		rw_destroy(&buf->b_lock);
 		kmem_cache_free(buf_cache, buf);
 		mutex_enter(&arc_eviction_mtx);
 	}
@@ -2464,6 +2474,7 @@
 
 	ASSERT(!refcount_is_zero(&pbuf->b_hdr->b_refcnt));
 	ASSERT3U((char *)bp - (char *)pbuf->b_data, <, pbuf->b_hdr->b_size);
+	rw_enter(&pbuf->b_lock, RW_READER);
 	rw_enter(&pbuf->b_hdr->b_datalock, RW_READER);
 
 	err = arc_read_nolock(pio, spa, bp, done, private, priority,
@@ -2471,6 +2482,7 @@
 
 	ASSERT3P(hdr, ==, pbuf->b_hdr);
 	rw_exit(&pbuf->b_hdr->b_datalock);
+	rw_exit(&pbuf->b_lock);
 	return (err);
 }
 
@@ -2610,6 +2622,7 @@
 			buf->b_efunc = NULL;
 			buf->b_private = NULL;
 			buf->b_next = NULL;
+			rw_init(&buf->b_lock, NULL, RW_DEFAULT, NULL);
 			hdr->b_buf = buf;
 			arc_get_data_buf(buf);
 			ASSERT(hdr->b_datacnt == 0);
@@ -2865,6 +2878,7 @@
 	buf->b_efunc = NULL;
 	buf->b_private = NULL;
 	buf->b_hdr = NULL;
+	rw_destroy(&buf->b_lock);
 	kmem_cache_free(buf_cache, buf);
 	return (1);
 }
@@ -2951,7 +2965,9 @@
 		nhdr->b_datacnt = 1;
 		nhdr->b_freeze_cksum = NULL;
 		(void) refcount_add(&nhdr->b_refcnt, tag);
+		rw_enter(&buf->b_lock, RW_WRITER);
 		buf->b_hdr = nhdr;
+		rw_exit(&buf->b_lock);
 		atomic_add_64(&arc_anon->arcs_size, blksz);
 	} else {
 		ASSERT(refcount_count(&hdr->b_refcnt) == 1);

--- uts/common/fs/zfs/sys/arc.h
+++ uts/common/fs/zfs/sys/arc.h
@@ -53,6 +53,7 @@
 	void			*b_data;
 	arc_evict_func_t	*b_efunc;
 	void			*b_private;
+	krwlock_t		 b_lock;
 };
 
 typedef enum arc_buf_contents {