With CONFIG_DEBUG_SLAB=y:
# Subtest: input_core 1..3 input: Test input device as /devices/virtual/input/input1 8<--- cut here --- Unable to handle kernel paging request at virtual address 6b6b6dd7 when read ... __lock_acquire from lock_acquire+0x26c/0x300 lock_acquire from _raw_spin_lock_irqsave+0x50/0x64 _raw_spin_lock_irqsave from devres_remove+0x20/0x7c devres_remove from devres_destroy+0x8/0x24 devres_destroy from input_free_device+0x2c/0x60 input_free_device from kunit_try_run_case+0x70/0x94 [kunit]
Without CONFIG_DEBUG_SLAB=y:
KTAP version 1 # Subtest: input_core 1..3 input: Test input device as /devices/virtual/input/input1 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 694 at lib/refcount.c:28 refcount_warn_saturate+0x54/0x100 refcount_t: underflow; use-after-free. ... Call Trace: [<0037cad4>] dump_stack+0xc/0x10 [<00377614>] __warn+0x7e/0xb4 [<0037768c>] warn_slowpath_fmt+0x42/0x62 [<001eee1c>] refcount_warn_saturate+0x54/0x100 [<000b1d34>] kfree_const+0x0/0x20 [<0036290a>] __kobject_del+0x0/0x6e [<001eee1c>] refcount_warn_saturate+0x54/0x100 [<00362a1a>] kobject_put+0xa2/0xb6 [<11965770>] kunit_generic_run_threadfn_adapter+0x0/0x1c [kunit]
As per the comments for input_allocate_device() and input_register_device(), input_free_device() must be called only to free devices that have not been registered. input_unregister_device() already calls input_put_device(), thus leading to a use-after-free.
Moreover, the kunit_suite.exit() method is called after every test case, even on failures. As the test itself already does cleanups in its failure paths, this may lead to a second use-after-free.
Fix the first issue by dropping the call to input_allocate_device() from input_test_exit(). Fix the second issue by making the cleanup code conditional on a successful test.
Fixes: fdefcbdd6f361841 ("Input: Add KUnit tests for some of the input core helper functions") Signed-off-by: Geert Uytterhoeven geert+renesas@glider.be --- drivers/input/tests/input_test.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/input/tests/input_test.c b/drivers/input/tests/input_test.c index e5a6c1ad2167c103..8b8ac3412a70d3b4 100644 --- a/drivers/input/tests/input_test.c +++ b/drivers/input/tests/input_test.c @@ -43,8 +43,8 @@ static void input_test_exit(struct kunit *test) { struct input_dev *input_dev = test->priv;
- input_unregister_device(input_dev); - input_free_device(input_dev); + if (input_dev) + input_unregister_device(input_dev); }
static void input_test_poll(struct input_dev *input) { }