[PATCH 6.6.y] kunit/overflow: Fix UB in overflow_allocation_test

[jianqi.ren.cn]

From: Ivan Orlov <ivan.orlov0322@xxxxxxxxx>

[ Upstream commit 92e9bac18124682c4b99ede9ee3bcdd68f121e92 ]

The 'device_name' array doesn't exist out of the
'overflow_allocation_test' function scope. However, it is being used as
a driver name when calling 'kunit_driver_create' from
'kunit_device_register'. It produces the kernel panic with KASAN
enabled.

Since this variable is used in one place only, remove it and pass the
device name into kunit_device_register directly as an ascii string.

Signed-off-by: Ivan Orlov <ivan.orlov0322@xxxxxxxxx>
Reviewed-by: David Gow <davidgow@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240815000431.401869-1-ivan.orlov0322@xxxxxxxxx
Signed-off-by: Kees Cook <kees@xxxxxxxxxx>
Signed-off-by: Jianqi Ren <jianqi.ren.cn@xxxxxxxxxxxxx>
Signed-off-by: He Zhe <zhe.he@xxxxxxxxxxxxx>
---
Verified the build test
---
 lib/overflow_kunit.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/overflow_kunit.c b/lib/overflow_kunit.c
index 34db0b3aa502..9493a1b28b9e 100644
--- a/lib/overflow_kunit.c
+++ b/lib/overflow_kunit.c
@@ -608,7 +608,6 @@ DEFINE_TEST_ALLOC(devm_kzalloc,  devm_kfree, 1, 1, 0);
 
 static void overflow_allocation_test(struct kunit *test)
 {
-	const char device_name[] = "overflow-test";
 	struct device *dev;
 	int count = 0;
 
@@ -618,7 +617,7 @@ static void overflow_allocation_test(struct kunit *test)
 } while (0)
 
 	/* Create dummy device for devm_kmalloc()-family tests. */
-	dev = root_device_register(device_name);
+	dev = root_device_register("overflow-test");
 	KUNIT_ASSERT_FALSE_MSG(test, IS_ERR(dev),
 			       "Cannot register test device\n");
 
-- 
2.34.1