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[PATCH] drm/tests: provide exit function

José Pekkarinen posted 1 patch 2 years, 5 months ago
There is a newer version of this series
drivers/gpu/drm/tests/drm_exec_test.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
[PATCH] drm/tests: provide exit function
Posted by José Pekkarinen 2 years, 5 months ago 
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
[  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.pekkarinen@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);
+
+	drm_dev_put(priv->drm);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->drm);
+
+	kunit_kfree(test, priv);
+}
+
 static void sanitycheck(struct kunit *test)
 {
 	struct drm_exec exec;
@@ -204,6 +217,7 @@ static struct kunit_case drm_exec_tests[] = {
 static struct kunit_suite drm_exec_test_suite = {
 	.name = "drm_exec",
 	.init = drm_exec_test_init,
+	.exit = drm_exec_test_exit,
 	.test_cases = drm_exec_tests,
 };
 
-- 
2.39.2
Re: [PATCH] drm/tests: provide exit function
Posted by Maxime Ripard 2 years, 5 months ago 
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.pekkarinen@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.

> +	drm_dev_put(priv->drm);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->drm);

This isn't needed with devm_drm_dev_alloc

> +	kunit_kfree(test, priv);

And that's not needed either, kunit actions will be run automatically.

Maxime
Re: [PATCH] drm/tests: provide exit function
Posted by José Pekkarinen 2 years, 5 months ago 
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.pekkarinen@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.
Re: [PATCH] drm/tests: provide exit function
Posted by mripard@kernel.org 2 years, 5 months ago 
On Wed, Sep 13, 2023 at 05:01:40PM +0300, José Pekkarinen wrote:
> 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.pekkarinen@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.

I mean, what is drm_kunit_helper_free_device calling?

Maxime
Re: [PATCH] drm/tests: provide exit function
Posted by José Pekkarinen 2 years, 5 months ago 
On 2023-09-13 17:41, mripard@kernel.org wrote:
> On Wed, Sep 13, 2023 at 05:01:40PM +0300, José Pekkarinen wrote:
>> 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.pekkarinen@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.
> 
> I mean, what is drm_kunit_helper_free_device calling?

     That seems to be triggering any registered release
action immediately, so it calls platform_device_del,
followed by platform_device_put, followed by
platform_driver_unregister. Reducing the patch to
just call the drm_dev_put that doesn't seem to happen
automatically still triggers this stacktrace:

[ 3300.409436] refcount_t: underflow; use-after-free.
[ 3300.409483] WARNING: CPU: 6 PID: 13758 at lib/refcount.c:28 
refcount_warn_saturate+0xcd/0x120
[ 3300.409504] Modules linked in: drm_exec_test drm_exec 
drm_kunit_helpers kunit snd_usb_audio snd_usbmidi_lib uvcvideo snd_ump 
snd_hwdep videobuf2_vmalloc snd_pcm videobuf2_memops snd
_rawmidi uvc videobuf2_v4l2 snd_seq_device snd_timer videodev snd 
soundcore videobuf2_common mc rfkill binfmt_misc intel_rapl_msr 
intel_rapl_common kvm_amd ccp rng_core kvm nls_ascii irqbypass nls_cp437 
crct10dif_pclmul crct10dif_common
  vfat crc32_pclmul fat ghash_clmulni_intel sha512_ssse3 sha512_generic 
aesni_intel crypto_simd cryptd iTCO_wdt pcspkr intel_pmc_bxt 
virtio_console iTCO_vendor_support intel_agp joydev evdev intel_gtt 
watchdog button serio_raw sg nft_ct
msr nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 parport_pc nf_tables 
ppdev lp libcrc32c parport nfnetlink loop fuse efi_pstore configfs 
efivarfs qemu_fw_cfg ip_tables x_tables autofs4 ext4 crc32c_generic 
crc16 mbcache jbd2 hid_generic us
bhid hid dm_mod virtio_gpu virtio_dma_buf drm_shmem_helper 
drm_kms_helper sr_mod virtio_net cdrom net_failover drm failover 
virtio_blk ahci
2023-09-13T18:21:01.438934+03:00 woodpecker kernel: [ 3300.410013]  
libahci virtio_pci libata xhci_pci virtio xhci_hcd i2c_i801 crc32c_intel 
virtio_pci_legacy_dev scsi_mod usbcore virtio_pci_modern_dev psmouse 
i2c_smbus scsi_common lpc_
ich usb_common virtio_ring
[ 3300.410081] CPU: 6 PID: 13758 Comm: kunit_try_catch Tainted: G    B   
          N 6.6.0-rc1+ #3
[ 3300.410092] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 
0.0.0 02/06/2015
[ 3300.410098] RIP: 0010:refcount_warn_saturate+0xcd/0x120
[ 3300.410113] Code: 0a 21 fc 01 01 e8 03 9d 7f ff 0f 0b eb 95 80 3d f9 
20 fc 01 00 75 8c 48 c7 c7 e0 10 a8 b9 c6 05 e9 20 fc 01 01 e8 e3 9c 7f 
ff <0f> 0b e9 72 ff ff ff 80 3d d4 20 fc
  01 00 0f 85 65 ff ff ff 48 c7
[ 3300.410122] RSP: 0018:ffff888284397bf0 EFLAGS: 00010286
[ 3300.410132] RAX: 0000000000000000 RBX: 0000000000000003 RCX: 
0000000000000000
[ 3300.410138] RDX: 0000000000000002 RSI: ffffffffb8567c64 RDI: 
ffffffffbb90c7a0
[ 3300.410145] RBP: ffff888271e3d004 R08: 0000000000000001 R09: 
ffffed1062726081
[ 3300.410151] R10: ffff88831393040b R11: 0000000000000001 R12: 
ffff888124145c80
[ 3300.410158] R13: ffff888284397c78 R14: ffffffffc0c11b20 R15: 
0000000000000010
[ 3300.410168] FS:  0000000000000000(0000) GS:ffff888313900000(0000) 
knlGS:0000000000000000
[ 3300.410176] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3300.410182] CR2: 00007ffdbe910148 CR3: 0000000119c3c000 CR4: 
0000000000350ee0
[ 3300.410191] Call Trace:
[ 3300.410197]  <TASK>
[ 3300.410203]  ? __warn+0xa1/0x1a0
[ 3300.410221]  ? refcount_warn_saturate+0xcd/0x120
[ 3300.410239]  ? report_bug+0x1f2/0x220
[ 3300.410258]  ? handle_bug+0x41/0x80
[ 3300.410272]  ? exc_invalid_op+0x13/0x40
[ 3300.410285]  ? asm_exc_invalid_op+0x16/0x20
[ 3300.410304]  ? preempt_count_sub+0x14/0xc0
[ 3300.410316]  ? refcount_warn_saturate+0xcd/0x120
[ 3300.410323]  release_nodes+0x83/0x160
[ 3300.410332]  devres_release_all+0xe6/0x130
[ 3300.410338]  ? __pfx_devres_release_all+0x10/0x10
[ 3300.410343]  ? mutex_unlock+0x80/0xd0
[ 3300.410349]  ? __pfx_mutex_unlock+0x10/0x10
[ 3300.410356]  device_unbind_cleanup+0x16/0xc0
[ 3300.410364]  device_release_driver_internal+0x28b/0x2e0
[ 3300.410372]  bus_remove_device+0x124/0x1d0
[ 3300.410378]  device_del+0x23d/0x580
[ 3300.410384]  ? __pfx_device_del+0x10/0x10
[ 3300.410389]  ? kasan_set_track+0x21/0x30
[ 3300.410395]  ? _raw_spin_lock_irqsave+0x98/0xf0
[ 3300.410402]  platform_device_del.part.0+0x19/0xe0
[ 3300.410408]  kunit_remove_resource+0xfa/0x140 [kunit]
[ 3300.410427]  kunit_cleanup+0x47/0xa0 [kunit]
[ 3300.410443]  ? __pfx_kunit_try_run_case_cleanup+0x10/0x10 [kunit]
[ 3300.410460]  ? __pfx_kunit_generic_run_threadfn_adapter+0x10/0x10 
[kunit]
[ 3300.410477]  kunit_generic_run_threadfn_adapter+0x29/0x50 [kunit]
[ 3300.410494]  kthread+0x184/0x1c0
[ 3300.410499]  ? __pfx_kthread+0x10/0x10
[ 3300.410503]  ret_from_fork+0x30/0x50
[ 3300.410509]  ? __pfx_kthread+0x10/0x10
[ 3300.410513]  ret_from_fork_asm+0x1b/0x30
[ 3300.410522]  </TASK>
[ 3300.410524] ---[ end trace 0000000000000000 ]---
[ 3300.411310]     ok 1 sanitycheck
[ 3300.422160]     ok 2 test_lock
[ 3300.433030]     ok 3 test_lock_unlock
[ 3300.443877]     ok 4 test_duplicates
[ 3300.454591]     ok 5 test_prepare
[ 3300.467181]     ok 6 test_prepare_array
[ 3300.479030]     ok 7 test_multiple_loops
[ 3300.479052] # drm_exec: pass:7 fail:0 skip:0 total:7
[ 3300.479065] # Totals: pass:7 fail:0 skip:0 total:7
[ 3300.479076] ok 1 drm_exec

     Thanks!

     José.
Re: [PATCH] drm/tests: provide exit function
Posted by Maxime Ripard 2 years, 5 months ago 
On Wed, Sep 13, 2023 at 07:35:57PM +0300, José Pekkarinen wrote:
> On 2023-09-13 17:41, mripard@kernel.org wrote:
> > On Wed, Sep 13, 2023 at 05:01:40PM +0300, José Pekkarinen wrote:
> > > 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.pekkarinen@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.
> > 
> > I mean, what is drm_kunit_helper_free_device calling?
> 
>     That seems to be triggering any registered release
> action immediately, so it calls platform_device_del,
> followed by platform_device_put, followed by
> platform_driver_unregister.


Please test with:
https://lore.kernel.org/all/20230907135339.7971-2-thomas.hellstrom@linux.intel.com/

Maxime
Re: [PATCH] drm/tests: provide exit function
Posted by José Pekkarinen 2 years, 5 months ago 
On 2023-09-14 15:00, Maxime Ripard wrote:
> On Wed, Sep 13, 2023 at 07:35:57PM +0300, José Pekkarinen wrote:
>> On 2023-09-13 17:41, mripard@kernel.org wrote:
>> > On Wed, Sep 13, 2023 at 05:01:40PM +0300, José Pekkarinen wrote:
>> > > 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.pekkarinen@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.
>> >
>> > I mean, what is drm_kunit_helper_free_device calling?
>> 
>>     That seems to be triggering any registered release
>> action immediately, so it calls platform_device_del,
>> followed by platform_device_put, followed by
>> platform_driver_unregister.
> 
> 
> Please test with:
> https://lore.kernel.org/all/20230907135339.7971-2-thomas.hellstrom@linux.intel.com/
> 
> Maxime

     Hi,

     Yes, I was looking into that road, but Thomas
was faster, here is the output of my tests after
applying Thomas patch:

[  874.063255] KTAP version 1
[  874.063262] 1..1
[  874.064550]     KTAP version 1
[  874.064555]     # Subtest: drm_modes_analog_tv
[  874.064559]     # module: drm_modes_test
[  874.064565]     1..4
[  874.076778]     ok 1 drm_test_modes_analog_tv_ntsc_480i
[  874.091584]     ok 2 drm_test_modes_analog_tv_ntsc_480i_inlined
[  874.104682]     ok 3 drm_test_modes_analog_tv_pal_576i
[  874.116266]     ok 4 drm_test_modes_analog_tv_pal_576i_inlined
[  874.116285] # drm_modes_analog_tv: pass:4 fail:0 skip:0 total:4
[  874.116297] # Totals: pass:4 fail:0 skip:0 total:4
[  874.116305] ok 1 drm_modes_analog_tv
[  888.785690] KTAP version 1
[  888.785697] 1..1
[  888.786186]     KTAP version 1
[  888.786192]     # Subtest: drm_exec
[  888.786196]     # module: drm_exec_test
[  888.786202]     1..7
[  888.796416]     ok 1 sanitycheck
[  888.807215]     ok 2 test_lock
[  888.820305]     ok 3 test_lock_unlock
[  888.829242]     ok 4 test_duplicates
[  888.840362]     ok 5 test_prepare
[  888.851022]     ok 6 test_prepare_array
[  888.865011]     ok 7 test_multiple_loops
[  888.865034] # drm_exec: pass:7 fail:0 skip:0 total:7
[  888.865044] # Totals: pass:7 fail:0 skip:0 total:7
[  888.865053] ok 2 drm_exec

Tested-by: José Pekkarinen<jose.pekkarinen@foxhound.fi>

     Thanks!

     José.

Patchew 2.1-devel-b67e4c2

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