diff --git a/userspace/units/fifo/pbdma/gm20b/nvgpu-pbdma-gm20b.c b/userspace/units/fifo/pbdma/gm20b/nvgpu-pbdma-gm20b.c
index 81f00c792..eb64eb1fb 100644
--- a/userspace/units/fifo/pbdma/gm20b/nvgpu-pbdma-gm20b.c
+++ b/userspace/units/fifo/pbdma/gm20b/nvgpu-pbdma-gm20b.c
@@ -145,6 +145,9 @@ int test_gm20b_pbdma_acquire_val(struct unit_module *m,
 	int i;
 	int err;
 
+	timeout = gm20b_pbdma_acquire_val(0);
+	assert(is_timeout_valid(m, timeout, 0));
+
 	for (i = 0; i < 32; i++) {
 		ms = (1ULL << i);
 		timeout = gm20b_pbdma_acquire_val(ms);
@@ -300,6 +303,7 @@ int test_gm20b_pbdma_handle_intr_0(struct unit_module *m,
 	u32 err_notifier;
 	bool recover;
 	int i;
+	int err;
 
 	assert((f->intr.pbdma.device_fatal_0 & pbdma_intr_0_memreq_pending_f()) != 0);
 
@@ -367,9 +371,19 @@ int test_gm20b_pbdma_handle_intr_0(struct unit_module *m,
 			assert(nvgpu_readl(g, pbdma_method2_r(pbdma_id)) != METHOD_SUBCH6);
 			assert(nvgpu_readl(g, pbdma_method3_r(pbdma_id)) != METHOD_SUBCH7);
 		}
-
 	}
 
+
+	/* trigger assert in pbdma_method1_r() */
+	pbdma_id = (0x100000000ULL - (u64)pbdma_method1_r(0) + 8191ULL) / 8192ULL;
+	err = EXPECT_BUG(
+		recover = gm20b_pbdma_handle_intr_0(g,
+			pbdma_id, /* invalid pbdma_id */
+			pbdma_intr_0_device_pending_f(),
+			&err_notifier)
+	);
+	assert(err != 0);
+
 	ret = UNIT_SUCCESS;
 done:
 	if (ret != UNIT_SUCCESS) {
diff --git a/userspace/units/fifo/pbdma/gm20b/nvgpu-pbdma-gm20b.h b/userspace/units/fifo/pbdma/gm20b/nvgpu-pbdma-gm20b.h
index b5fecc9c9..e38b3936d 100644
--- a/userspace/units/fifo/pbdma/gm20b/nvgpu-pbdma-gm20b.h
+++ b/userspace/units/fifo/pbdma/gm20b/nvgpu-pbdma-gm20b.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2019-2020, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -53,6 +53,8 @@ struct gk20a;
  * - Check that delta between expected and actual values is lower than
  *   1024 * (1 << exponent).
  * - Check that BUG_ON occurs on overflow while converting ms to ns.
+ * - Check that enable bit is not set when 0 is passed to
+ *   gm20b_pbdma_acquire_val.
  *
  * Output: Returns PASS if all branches gave expected results. FAIL otherwise.
  */
@@ -116,6 +118,8 @@ int test_gm20b_pbdma_handle_intr(struct unit_module *m,
  *   - pbdma_intr_0_device: Check that all pbdma subch methods and header
  *     have been reset and that recover is true.
  * - Check that recover is false, when none of above interrupt is raised.
+ * - Check that BUG() occurs when passing an invalid pbdma_id that
+ *   causes an overflow in register computation.
  *
  * Output: Returns PASS if all branches gave expected results. FAIL otherwise.
  */