diff --git a/lib/accel/accel_engine.c b/lib/accel/accel_engine.c
index 058e29ce1..c2e0e34af 100644
--- a/lib/accel/accel_engine.c
+++ b/lib/accel/accel_engine.c
@@ -298,7 +298,7 @@ spdk_accel_submit_fill(struct spdk_io_channel *ch, void *dst, uint8_t fill, uint
 	}
 
 	accel_task->dst = dst;
-	accel_task->fill_pattern = fill;
+	memset(&accel_task->fill_pattern, fill, sizeof(uint64_t));
 	accel_task->nbytes = nbytes;
 	accel_task->flags = flags;
 	accel_task->op_code = ACCEL_OPCODE_MEMFILL;
diff --git a/module/accel/idxd/accel_engine_idxd.c b/module/accel/idxd/accel_engine_idxd.c
index f6bf8e0af..330318501 100644
--- a/module/accel/idxd/accel_engine_idxd.c
+++ b/module/accel/idxd/accel_engine_idxd.c
@@ -144,7 +144,6 @@ _process_single_task(struct spdk_io_channel *ch, struct spdk_accel_task *task)
 {
 	struct idxd_io_channel *chan = spdk_io_channel_get_ctx(ch);
 	int rc = 0;
-	uint8_t fill_pattern = (uint8_t)task->fill_pattern;
 	struct iovec *iov;
 	uint32_t iovcnt;
 	struct iovec siov = {};
@@ -179,7 +178,6 @@ _process_single_task(struct spdk_io_channel *ch, struct spdk_accel_task *task)
 		rc = spdk_idxd_submit_compare(chan->chan, &siov, 1, &diov, 1, flags, idxd_done, task);
 		break;
 	case ACCEL_OPCODE_MEMFILL:
-		memset(&task->fill_pattern, fill_pattern, sizeof(uint64_t));
 		diov.iov_base = task->dst;
 		diov.iov_len = task->nbytes;
 		if (task->flags & ACCEL_FLAG_PERSISTENT) {
diff --git a/test/unit/lib/accel/accel.c/accel_engine_ut.c b/test/unit/lib/accel/accel.c/accel_engine_ut.c
index 06eef7ccd..c98d89645 100644
--- a/test/unit/lib/accel/accel.c/accel_engine_ut.c
+++ b/test/unit/lib/accel/accel.c/accel_engine_ut.c
@@ -461,6 +461,7 @@ test_spdk_accel_submit_fill(void)
 	void *dst;
 	void *src;
 	uint8_t fill = 0xf;
+	uint64_t fill64;
 	uint64_t nbytes = TEST_SUBMIT_SIZE;
 	void *cb_arg = NULL;
 	int rc;
@@ -473,6 +474,7 @@ test_spdk_accel_submit_fill(void)
 	src = calloc(1, TEST_SUBMIT_SIZE);
 	SPDK_CU_ASSERT_FATAL(src != NULL);
 	memset(src, fill, TEST_SUBMIT_SIZE);
+	memset(&fill64, fill, sizeof(uint64_t));
 
 	/* Fail with no tasks on _get_task() */
 	rc = spdk_accel_submit_fill(g_ch, dst, fill, nbytes, flags, dummy_submit_cb_fn, cb_arg);
@@ -492,7 +494,7 @@ test_spdk_accel_submit_fill(void)
 	rc = spdk_accel_submit_fill(g_ch, dst, fill, nbytes, flags, dummy_submit_cb_fn, cb_arg);
 	CU_ASSERT(rc == 0);
 	CU_ASSERT(task.dst == dst);
-	CU_ASSERT(task.fill_pattern == fill);
+	CU_ASSERT(task.fill_pattern == fill64);
 	CU_ASSERT(task.op_code == ACCEL_OPCODE_MEMFILL);
 	CU_ASSERT(task.nbytes == nbytes);
 	CU_ASSERT(task.flags == 0);
@@ -512,7 +514,7 @@ test_spdk_accel_submit_fill(void)
 	rc = spdk_accel_submit_fill(g_ch, dst, fill, nbytes, flags, dummy_submit_cb_fn, cb_arg);
 	CU_ASSERT(rc == 0);
 	CU_ASSERT(task.dst == dst);
-	CU_ASSERT(task.fill_pattern == fill);
+	CU_ASSERT(task.fill_pattern == fill64);
 	CU_ASSERT(task.op_code == ACCEL_OPCODE_MEMFILL);
 	CU_ASSERT(task.nbytes == nbytes);
 	CU_ASSERT(task.flags == 0);