In __drm_kunit_helper_alloc_drm_device_with_driver(), a drm_driver is allocated with kunit_kzalloc. If the dev argument was allocated by drm_kunit_helper_alloc_device, its deferred actions would access the already deallocated drm_driver. To fix that, move the deferred to the top of the resource stack. ================================================================== BUG: KASAN: slab-use-after-free in devm_drm_dev_init_release+0x54/0xb0 Read of size 8 at addr 0000000063194e28 by task kunit_try_catch/127 CPU: 0 PID: 127 Comm: kunit_try_catch Tainted: G W N 6.5.0-rc2-00620-g4f77e58c6017 #35 Stack: 606c9a22 606c9a22 00000000 606c9a22 6056b8fe 63033b10 00000000 60040850 63033a80 60574ca4 60574c4a 63033b10 Call Trace: [<600295a2>] show_stack+0x202/0x220 [<6056b8fe>] ? _printk+0x0/0x78 [<60040850>] ? um_set_signals+0x0/0x40 [<60574ca4>] dump_stack_lvl+0x5a/0x6b [<60574c4a>] ? dump_stack_lvl+0x0/0x6b [<6019d40d>] print_report+0x1bd/0x670 [<6056b96b>] ? _printk+0x6d/0x78 [<6056b8fe>] ? _printk+0x0/0x78 [<6019f0e6>] ? kasan_complete_mode_report_info+0x116/0x180 [<603d16d4>] ? devm_drm_dev_init_release+0x54/0xb0 [<6019db14>] kasan_report+0x184/0x1b0 [<603d16d4>] ? devm_drm_dev_init_release+0x54/0xb0 [<6019e770>] ? __asan_load8+0x0/0x80 [<6019e770>] ? __asan_load8+0x0/0x80 [<6019e7ec>] __asan_load8+0x7c/0x80 [<603d16d4>] devm_drm_dev_init_release+0x54/0xb0 [<6019e770>] ? __asan_load8+0x0/0x80 [<603d1680>] ? devm_drm_dev_init_release+0x0/0xb0 [<604b0bde>] devm_action_release+0x2e/0x40 [<604afd60>] devres_release_all+0x100/0x170 [<6019e770>] ? __asan_load8+0x0/0x80 [<6019e770>] ? __asan_load8+0x0/0x80 [<604a7f7d>] device_release_driver_internal+0x39d/0x510 [<6027d7f0>] ? sysfs_remove_link+0x0/0x50 [<6019e770>] ? __asan_load8+0x0/0x80 [<604a8104>] device_release_driver+0x14/0x20 [<604a3592>] bus_remove_device+0x1e2/0x200 [<6019e770>] ? __asan_load8+0x0/0x80 [<6049de5a>] device_del+0x3ba/0x850 [<6019f790>] ? kasan_quarantine_put+0x0/0x170 [<60137bad>] ? kfree+0x5d/0x80 [<6019e7f0>] ? __asan_store8+0x0/0x90 [<6019e770>] ? __asan_load8+0x0/0x80 [<604475a0>] ? kunit_action_platform_device_del+0x0/0x20 [<604ad4b0>] platform_device_del+0x40/0x140 [<601957f3>] ? __kmem_cache_free+0xc3/0x230 [<6019e7f0>] ? __asan_store8+0x0/0x90 [<6019e770>] ? __asan_load8+0x0/0x80 [<604475a0>] ? kunit_action_platform_device_del+0x0/0x20 [<604475b0>] kunit_action_platform_device_del+0x10/0x20 [<6031bf80>] __kunit_action_free+0x30/0x40 [<6031bf50>] ? __kunit_action_free+0x0/0x40 [<6031bae4>] kunit_remove_resource+0xf4/0x150 [<6019e770>] ? __asan_load8+0x0/0x80 [<6019e770>] ? __asan_load8+0x0/0x80 [<60040850>] ? um_set_signals+0x0/0x40 [<6019e770>] ? __asan_load8+0x0/0x80 [<6031b396>] kunit_cleanup+0xb6/0x140 [<605848cd>] ? __schedule+0x6bd/0x7a0 [<6019e7f0>] ? __asan_store8+0x0/0x90 [<6019e770>] ? __asan_load8+0x0/0x80 [<6031b715>] kunit_try_run_case_cleanup+0x95/0xb0 [<6019e770>] ? __asan_load8+0x0/0x80 [<6019e770>] ? __asan_load8+0x0/0x80 [<6031b680>] ? kunit_try_run_case_cleanup+0x0/0xb0 [<6031e240>] kunit_generic_run_threadfn_adapter+0x30/0x60 [<6008d15e>] kthread+0x28e/0x2e0 [<6031e210>] ? kunit_generic_run_threadfn_adapter+0x0/0x60 [<6019e7f0>] ? __asan_store8+0x0/0x90 [<6008ced0>] ? kthread+0x0/0x2e0 [<6019e770>] ? __asan_load8+0x0/0x80 [<600270e6>] new_thread_handler+0x136/0x1a0 Allocated by task 126: save_stack_trace+0x5b/0x70 stack_trace_save+0x7a/0xa0 kasan_set_track+0x6c/0xa0 kasan_save_alloc_info+0x26/0x30 __kasan_kmalloc+0x91/0xa0 __kmalloc+0xb9/0x110 kunit_kmalloc_array+0x23/0x60 drm_test_fb_build_fourcc_list+0x8b/0x390 kunit_try_run_case+0xab/0x140 kunit_generic_run_threadfn_adapter+0x30/0x60 kthread+0x28e/0x2e0 new_thread_handler+0x136/0x1a0 Freed by task 127: save_stack_trace+0x5b/0x70 stack_trace_save+0x7a/0xa0 kasan_set_track+0x6c/0xa0 kasan_save_free_info+0x30/0x50 ____kasan_slab_free+0x12c/0x190 __kasan_slab_free+0x18/0x20 __kmem_cache_free+0xc3/0x230 kfree+0x5d/0x80 __kunit_action_free+0x30/0x40 kunit_remove_resource+0xf4/0x150 kunit_cleanup+0xb6/0x140 kunit_try_run_case_cleanup+0x95/0xb0 kunit_generic_run_threadfn_adapter+0x30/0x60 kthread+0x28e/0x2e0 new_thread_handler+0x136/0x1a0 The buggy address belongs to the object at 0000000063194e00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 40 bytes inside of freed 256-byte region [0000000063194e00, 0000000063194f00) The buggy address belongs to the physical page: page:00000000d99927cc refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3194 flags: 0x200(slab|zone=0) page_type: 0xffffffff() raw: 0000000000000200 0000000062401900 0000000000000122 0000000000000000 raw: 0000000000000000 0000000080080008 00000001ffffffff page dumped because: kasan: bad access detected Memory state around the buggy address: 0000000063194d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc 0000000063194d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >0000000063194e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ 0000000063194e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 0000000063194f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Signed-off-by: Arthur Grillo <arthurgrillo@xxxxxxxxxx> --- drivers/gpu/drm/tests/drm_kunit_helpers.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/gpu/drm/tests/drm_kunit_helpers.c b/drivers/gpu/drm/tests/drm_kunit_helpers.c index 3150dbc647ee..655cedf7ab13 100644 --- a/drivers/gpu/drm/tests/drm_kunit_helpers.c +++ b/drivers/gpu/drm/tests/drm_kunit_helpers.c @@ -129,6 +129,7 @@ __drm_kunit_helper_alloc_drm_device_with_driver(struct kunit *test, const struct drm_driver *driver) { struct drm_device *drm; + struct platform_device *pdev = to_platform_device(dev); void *container; int ret; @@ -143,6 +144,21 @@ __drm_kunit_helper_alloc_drm_device_with_driver(struct kunit *test, if (ret) return ERR_PTR(ret); + ret = kunit_move_action_to_top_or_reset(test, + kunit_action_platform_driver_unregister, + &fake_platform_driver); + KUNIT_ASSERT_EQ(test, ret, 0); + + ret = kunit_move_action_to_top_or_reset(test, + kunit_action_platform_device_put, + pdev); + KUNIT_ASSERT_EQ(test, ret, 0); + + ret = kunit_move_action_to_top_or_reset(test, + kunit_action_platform_device_del, + pdev); + KUNIT_ASSERT_EQ(test, ret, 0); + return drm; } EXPORT_SYMBOL_GPL(__drm_kunit_helper_alloc_drm_device_with_driver); -- 2.41.0