On 2023-09-13 12:50, Maxime Ripard wrote:
Hi,
On Wed, Sep 13, 2023 at 11:32:23AM +0300, José Pekkarinen wrote:
Running drm_exec_test by modprobing the module I
observe the following output:
[ 424.471936] KTAP version 1
[ 424.471942] 1..1
[ 424.472446] KTAP version 1
[ 424.472450] # Subtest: drm_exec
[ 424.472453] # module: drm_exec_test
[ 424.472459] 1..7
[ 424.479082]
==================================================================
[ 424.479095] BUG: KASAN: slab-use-after-free in
drm_dev_put.part.0+0x4b/0x90 [drm]
[ 424.479426] Read of size 8 at addr ffff888132d3e028 by task
kunit_try_catch/1866
[ 424.479436]
[ 424.479442] CPU: 1 PID: 1866 Comm: kunit_try_catch Tainted: G
N 6.6.0-rc1-dirty #2
That's suspicious
[ 424.479446] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
BIOS 0.0.0 02/06/2015
[ 424.479446] Call Trace:
[ 424.479446] <TASK>
[ 424.479446] dump_stack_lvl+0x43/0x60
[ 424.479446] print_report+0xcf/0x660
[ 424.479446] ? __virt_addr_valid+0xd9/0x160
[ 424.479446] ? drm_dev_put.part.0+0x4b/0x90 [drm]
[ 424.479446] kasan_report+0xda/0x110
[ 424.479446] ? drm_dev_put.part.0+0x4b/0x90 [drm]
[ 424.479446] drm_dev_put.part.0+0x4b/0x90 [drm]
[ 424.479446] release_nodes+0x83/0x160
[ 424.479446] devres_release_all+0xe6/0x130
[ 424.479446] ? __pfx_devres_release_all+0x10/0x10
[ 424.479446] ? mutex_unlock+0x80/0xd0
[ 424.479446] ? __pfx_mutex_unlock+0x10/0x10
[ 424.479446] device_unbind_cleanup+0x16/0xc0
[ 424.479446] device_release_driver_internal+0x28b/0x2e0
[ 424.479446] bus_remove_device+0x124/0x1d0
[ 424.479446] device_del+0x23d/0x580
[ 424.479446] ? __pfx_device_del+0x10/0x10
[ 424.479446] ? kasan_set_track+0x21/0x30
[ 424.479446] ? _raw_spin_lock_irqsave+0x98/0xf0
[ 424.479446] platform_device_del.part.0+0x19/0xe0
[ 424.479446] kunit_remove_resource+0xfa/0x140 [kunit]
[ 424.479446] kunit_cleanup+0x47/0xa0 [kunit]
[ 424.479446] ? __pfx_kunit_try_run_case_cleanup+0x10/0x10 [kunit]
[ 424.479446] ? __pfx_kunit_generic_run_threadfn_adapter+0x10/0x10
[kunit]
[ 424.479446] kunit_generic_run_threadfn_adapter+0x29/0x50 [kunit]
[ 424.479446] kthread+0x184/0x1c0
[ 424.479446] ? __pfx_kthread+0x10/0x10
[ 424.479446] ret_from_fork+0x30/0x50
[ 424.479446] ? __pfx_kthread+0x10/0x10
[ 424.479446] ret_from_fork_asm+0x1b/0x30
[ 424.479446] </TASK>
[ 424.479446]
[ 424.479446] Allocated by task 1865:
[ 424.479446] kasan_save_stack+0x2f/0x50
[ 424.479446] kasan_set_track+0x21/0x30
[ 424.479446] __kasan_kmalloc+0xa6/0xb0
[ 424.479446] __kmalloc+0x5d/0x160
[ 424.479446] kunit_kmalloc_array+0x1c/0x50 [kunit]
[ 424.479446] drm_exec_test_init+0xef/0x260 [drm_exec_test]
[ 424.479446] kunit_try_run_case+0x6e/0x100 [kunit]
[ 424.479446] kunit_generic_run_threadfn_adapter+0x29/0x50 [kunit]
[ 424.479446] kthread+0x184/0x1c0
[ 424.479446] ret_from_fork+0x30/0x50
[ 424.479446] ret_from_fork_asm+0x1b/0x30
[ 424.479446]
[ 424.479446] Freed by task 1866:
[ 424.479446] kasan_save_stack+0x2f/0x50
[ 424.479446] kasan_set_track+0x21/0x30
[ 424.479446] kasan_save_free_info+0x27/0x40
[ 424.479446] ____kasan_slab_free+0x166/0x1c0
[ 424.479446] slab_free_freelist_hook+0x9f/0x1e0
[ 424.479446] __kmem_cache_free+0x187/0x2d0
[ 424.479446] kunit_remove_resource+0xfa/0x140 [kunit]
[ 424.479446] kunit_cleanup+0x47/0xa0 [kunit]
[ 424.479446] kunit_generic_run_threadfn_adapter+0x29/0x50 [kunit]
[ 424.479446] kthread+0x184/0x1c0
[ 424.479446] ret_from_fork+0x30/0x50
[ 424.479446] ret_from_fork_asm+0x1b/0x30
[ 424.479446]
[ 424.479446] The buggy address belongs to the object at
ffff888132d3e000
[ 424.479446] which belongs to the cache kmalloc-256 of size 256
[ 424.479446] The buggy address is located 40 bytes inside of
[ 424.479446] freed 256-byte region [ffff888132d3e000,
ffff888132d3e100)
[ 424.479446]
[ 424.479446] The buggy address belongs to the physical page:
[ 424.479446] page:0000000092ff6551 refcount:1 mapcount:0
mapping:0000000000000000 index:0xffff888132d3f600 pfn:0x132d3c
[ 424.479446] head:0000000092ff6551 order:2 entire_mapcount:0
nr_pages_mapped:0 pincount:0
[ 424.479446] ksm flags:
0x17ffffc0000840(slab|head|node=0|zone=2|lastcpupid=0x1fffff)
[ 424.479446] page_type: 0xffffffff()
[ 424.479446] raw: 0017ffffc0000840 ffff888100042b40 ffffea00042c8000
dead000000000003
[ 424.479446] raw: ffff888132d3f600 000000008020001f 00000001ffffffff
0000000000000000
[ 424.479446] page dumped because: kasan: bad access detected
[ 424.479446]
[ 424.479446] Memory state around the buggy address:
[ 424.479446] ffff888132d3df00: fc fc fc fc fc fc fc fc fc fc fc fc
fc fc fc fc
[ 424.479446] ffff888132d3df80: fc fc fc fc fc fc fc fc fc fc fc fc
fc fc fc fc
[ 424.479446] >ffff888132d3e000: fa fb fb fb fb fb fb fb fb fb fb fb
fb fb fb fb
[ 424.479446] ^
[ 424.479446] ffff888132d3e080: fb fb fb fb fb fb fb fb fb fb fb fb
fb fb fb fb
[ 424.479446] ffff888132d3e100: fc fc fc fc fc fc fc fc fc fc fc fc
fc fc fc fc
[ 424.479446]
==================================================================
[ 424.481686] Disabling lock debugging due to kernel taint
[ 424.484124] not ok 1 sanitycheck
[ 424.492981] ok 2 test_lock
[ 424.503610] ok 3 test_lock_unlock
[ 424.515058] ok 4 test_duplicates
[ 424.530453] ok 5 test_prepare
[ 424.539099] ok 6 test_prepare_array
[ 424.550730] ok 7 test_multiple_loops
[ 424.550743] # drm_exec: pass:6 fail:1 skip:0 total:7
[ 424.550750] # Totals: pass:6 fail:1 skip:0 total:7
[ 424.550756] not ok 5 drm_exec
The ouptut suggest the init function is allocating a drm_device
that is not being freed. This patch provides the function and
add it to the kunit_suite to produce the following result of
the test:
[ 3363.342560] KTAP version 1
[ 3363.342571] 1..1
[ 3363.343090] KTAP version 1
[ 3363.343095] # Subtest: drm_exec
[ 3363.343098] # module: drm_exec_test
[ 3363.343103] 1..7
[ 3363.353659] ok 1 sanitycheck
[ 3363.364281] ok 2 test_lock
[ 3363.375616] ok 3 test_lock_unlock
[ 3363.388741] ok 4 test_duplicates
[ 3363.402544] ok 5 test_prepare
[ 3363.413163] ok 6 test_prepare_array
[ 3363.424614] ok 7 test_multiple_loops
[ 3363.424630] # drm_exec: pass:7 fail:0 skip:0 total:7
[ 3363.424637] # Totals: pass:7 fail:0 skip:0 total:7
[ 3363.424643] ok 1 drm_exec
Signed-off-by: José Pekkarinen <jose.pekkari...@foxhound.fi>
---
drivers/gpu/drm/tests/drm_exec_test.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/gpu/drm/tests/drm_exec_test.c
b/drivers/gpu/drm/tests/drm_exec_test.c
index 563949d777dd..7ff6bc6467d4 100644
--- a/drivers/gpu/drm/tests/drm_exec_test.c
+++ b/drivers/gpu/drm/tests/drm_exec_test.c
@@ -42,6 +42,19 @@ static int drm_exec_test_init(struct kunit *test)
return 0;
}
+static void drm_exec_test_exit(struct kunit *test)
+{
+ struct drm_exec_priv *priv = test->priv;
+
+ drm_kunit_helper_free_device(test, priv->dev);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev);
This shouldn't be necessary at all since 4f2b0b583baa.
Reading this suggested patch I see only references
to platform_driver_unregister, platform_device_put, and
platform_device_del, not the ones used in this patch.
Thanks!
José.
