[PATCH 7/7] iommu/arm-smmu-v3-test: Fix UBSAN error

[Mostafa Saleh]

struct arm_smmu_invs marks its flexible array member inv[] with the
__counted_by(max_invs).

arm_smmu_v3_invs_test() uses invs1 to invs5 which has num_invs = 3
but omit max_invs.

This causes the following UBSAN error:
[    2.333240] UBSAN: array-index-out-of-bounds in drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c:1116:21
[    2.333604]     # arm_smmu_v3_invs_test: lib/ubsan.c:228: array-index-out-of-bounds in drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
[    2.334129] index 1 is out of range for type 'struct arm_smmu_inv[] __counted_by(max_invs)' (aka 'struct arm_smmu_inv[]')
[    2.335375] CPU: 6 UID: 0 PID: 155 Comm: kunit_try_catch Tainted: G                 N  7.2.0-g8dcb331fbb72 #2 PREEMPT
[    2.335759] Tainted: [N]=TEST
[    2.335791] Hardware name: linux,dummy-virt (DT)
[    2.336254] Call trace:
[    2.336932]  show_stack+0x18/0x24 (C)
[    2.338443]  __dump_stack+0x28/0x38
[    2.338494]  dump_stack_lvl+0x54/0x6c
[    2.338518]  dump_stack+0x18/0x24
[    2.338541]  ubsan_epilogue+0x10/0x44
[    2.338565]  __ubsan_handle_out_of_bounds+0xb8/0xbc
[    2.338834]  arm_smmu_invs_merge+0x688/0x8ac
[    2.338862]  arm_smmu_v3_invs_test+0xd4/0x598
[    2.338890]  kunit_try_run_case+0x64/0x160
[    2.338914]  kunit_generic_run_threadfn_adapter+0x28/0x4c
[    2.338955]  kthread+0x10c/0x12c
[    2.338984]  ret_from_fork+0x10/0x20
[    2.339433] ---[ end trace ]---

Explicitly set max_invs = 3 on the test arrays to match the number of
elements.

Fixes: 15a2a5645ad7 ("iommu/arm-smmu-v3: Introduce a per-domain arm_smmu_invs array")
Signed-off-by: Mostafa Saleh <smostafa at google.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c
index 244cf34e5a0b..e52a7d95c919 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c
@@ -654,6 +654,7 @@ static void arm_smmu_v3_invs_test_verify(struct kunit *test,
 }
 
 static struct arm_smmu_invs invs1 = {
+	.max_invs = 3,
 	.num_invs = 3,
 	.inv = { { .type = INV_TYPE_S2_VMID, .id = 1, },
 		 { .type = INV_TYPE_S2_VMID_S1_CLEAR, .id = 1, },
@@ -661,6 +662,7 @@ static struct arm_smmu_invs invs1 = {
 };
 
 static struct arm_smmu_invs invs2 = {
+	.max_invs = 3,
 	.num_invs = 3,
 	.inv = { { .type = INV_TYPE_S2_VMID, .id = 1, }, /* duplicated */
 		 { .type = INV_TYPE_ATS, .id = 4, },
@@ -668,6 +670,7 @@ static struct arm_smmu_invs invs2 = {
 };
 
 static struct arm_smmu_invs invs3 = {
+	.max_invs = 3,
 	.num_invs = 3,
 	.inv = { { .type = INV_TYPE_S2_VMID, .id = 1, }, /* duplicated */
 		 { .type = INV_TYPE_ATS, .id = 5, }, /* recover a trash */
@@ -675,6 +678,7 @@ static struct arm_smmu_invs invs3 = {
 };
 
 static struct arm_smmu_invs invs4 = {
+	.max_invs = 3,
 	.num_invs = 3,
 	.inv = { { .type = INV_TYPE_ATS, .id = 10, .ssid = 1 },
 		 { .type = INV_TYPE_ATS, .id = 10, .ssid = 3 },
@@ -682,6 +686,7 @@ static struct arm_smmu_invs invs4 = {
 };
 
 static struct arm_smmu_invs invs5 = {
+	.max_invs = 3,
 	.num_invs = 3,
 	.inv = { { .type = INV_TYPE_ATS, .id = 10, .ssid = 2 },
 		 { .type = INV_TYPE_ATS, .id = 10, .ssid = 3 }, /* duplicate */
-- 
2.55.0.897.gb25b4bd76c-goog