dri-devel.lists.freedesktop.org archive mirror
 help / color / mirror / Atom feed
* [PATCH 4.19.y] drm/vkms: call drm_atomic_helper_shutdown before drm_dev_put()
@ 2024-04-03  9:47 Guo Mengqi
  2024-04-05  9:30 ` Greg KH
  0 siblings, 1 reply; 4+ messages in thread
From: Guo Mengqi @ 2024-04-03  9:47 UTC (permalink / raw)
  To: airlied, dri-devel, stable; +Cc: xuqiang36, zhangchangzhong

commit 73a82b22963d ("drm/atomic: Fix potential use-after-free
in nonblocking commits") introduced drm_dev_get/put() to
drm_atomic_helper_shutdown(). And this cause problem in vkms driver exit
process.

vkms_exit()
  drm_dev_put()
    vkms_release()
      drm_atomic_helper_shutdown()
        drm_dev_get()
        drm_dev_put()
          vkms_release()    ------ null pointer access

Using 4.19 stable x86 image on qemu, below stacktrace can be triggered by
load and unload vkms.ko.

root:~ # insmod vkms.ko
[  142.135449] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[  142.138713] [drm] Driver supports precise vblank timestamp query.
[  142.142390] [drm] Initialized vkms 1.0.0 20180514 for virtual device on minor 0
root:~ # rmmod vkms.ko
[  144.093710] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0
[  144.097491] PGD 800000023624e067 P4D 800000023624e067 PUD 22ab59067 PMD 0
[  144.100802] Oops: 0000 [#1] SMP PTI
[  144.102502] CPU: 0 PID: 3615 Comm: rmmod Not tainted 4.19.310 #1
[  144.104452] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
[  144.107238] RIP: 0010:device_del+0x34/0x3a0
...
[  144.131323] Call Trace:
[  144.131962]  ? __die+0x7d/0xc0
[  144.132711]  ? no_context+0x152/0x3b0
[  144.133605]  ? wake_up_q+0x70/0x70
[  144.134436]  ? __do_page_fault+0x342/0x4b0
[  144.135445]  ? __switch_to_asm+0x41/0x70
[  144.136416]  ? __switch_to_asm+0x35/0x70
[  144.137366]  ? page_fault+0x1e/0x30
[  144.138214]  ? __drm_atomic_state_free+0x51/0x60
[  144.139331]  ? device_del+0x34/0x3a0
[  144.140197]  platform_device_del.part.14+0x19/0x70
[  144.141348]  platform_device_unregister+0xe/0x20
[  144.142458]  vkms_release+0x10/0x30 [vkms]
[  144.143449]  __drm_atomic_helper_disable_all.constprop.31+0x13b/0x150
[  144.144980]  drm_atomic_helper_shutdown+0x4b/0x90
[  144.146102]  vkms_release+0x18/0x30 [vkms]
[  144.147107]  vkms_exit+0x29/0x8ec [vkms]
[  144.148053]  __x64_sys_delete_module+0x155/0x220
[  144.149168]  do_syscall_64+0x43/0x100
[  144.150056]  entry_SYSCALL_64_after_hwframe+0x5c/0xc1

It seems that the proper unload sequence is:
	drm_atomic_helper_shutdown();
	drm_dev_put();

Just put drm_atomic_helper_shutdown() before drm_dev_put()
should solve the problem.

Note that vkms exit code is refactored by 53d77aaa3f76 ("drm/vkms: Use
devm_drm_dev_alloc") in tags/v5.10-rc1.

So this bug only exists on 4.19 and 5.4.

Fixes: 73a82b22963d ("drm/atomic: Fix potential use-after-free in nonblocking commits")
Signed-off-by: Guo Mengqi <guomengqi3@huawei.com>
---
 drivers/gpu/drm/vkms/vkms_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index b1201c18d3eb..d32e08f17427 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -39,7 +39,6 @@ static void vkms_release(struct drm_device *dev)
 	struct vkms_device *vkms = container_of(dev, struct vkms_device, drm);
 
 	platform_device_unregister(vkms->platform);
-	drm_atomic_helper_shutdown(&vkms->drm);
 	drm_mode_config_cleanup(&vkms->drm);
 	drm_dev_fini(&vkms->drm);
 }
@@ -137,6 +136,7 @@ static void __exit vkms_exit(void)
 	}
 
 	drm_dev_unregister(&vkms_device->drm);
+	drm_atomic_helper_shutdown(&vkms_device->drm);
 	drm_dev_put(&vkms_device->drm);
 
 	kfree(vkms_device);
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH 4.19.y] drm/vkms: call drm_atomic_helper_shutdown before drm_dev_put()
  2024-04-03  9:47 [PATCH 4.19.y] drm/vkms: call drm_atomic_helper_shutdown before drm_dev_put() Guo Mengqi
@ 2024-04-05  9:30 ` Greg KH
  2024-04-09  2:38   ` guomengqi (A)
  0 siblings, 1 reply; 4+ messages in thread
From: Greg KH @ 2024-04-05  9:30 UTC (permalink / raw)
  To: Guo Mengqi; +Cc: airlied, dri-devel, stable, xuqiang36, zhangchangzhong

On Wed, Apr 03, 2024 at 05:47:16PM +0800, Guo Mengqi wrote:
> commit 73a82b22963d ("drm/atomic: Fix potential use-after-free
> in nonblocking commits") introduced drm_dev_get/put() to
> drm_atomic_helper_shutdown(). And this cause problem in vkms driver exit
> process.
> 
> vkms_exit()
>   drm_dev_put()
>     vkms_release()
>       drm_atomic_helper_shutdown()
>         drm_dev_get()
>         drm_dev_put()
>           vkms_release()    ------ null pointer access
> 
> Using 4.19 stable x86 image on qemu, below stacktrace can be triggered by
> load and unload vkms.ko.
> 
> root:~ # insmod vkms.ko
> [  142.135449] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
> [  142.138713] [drm] Driver supports precise vblank timestamp query.
> [  142.142390] [drm] Initialized vkms 1.0.0 20180514 for virtual device on minor 0
> root:~ # rmmod vkms.ko
> [  144.093710] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0
> [  144.097491] PGD 800000023624e067 P4D 800000023624e067 PUD 22ab59067 PMD 0
> [  144.100802] Oops: 0000 [#1] SMP PTI
> [  144.102502] CPU: 0 PID: 3615 Comm: rmmod Not tainted 4.19.310 #1
> [  144.104452] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
> [  144.107238] RIP: 0010:device_del+0x34/0x3a0
> ...
> [  144.131323] Call Trace:
> [  144.131962]  ? __die+0x7d/0xc0
> [  144.132711]  ? no_context+0x152/0x3b0
> [  144.133605]  ? wake_up_q+0x70/0x70
> [  144.134436]  ? __do_page_fault+0x342/0x4b0
> [  144.135445]  ? __switch_to_asm+0x41/0x70
> [  144.136416]  ? __switch_to_asm+0x35/0x70
> [  144.137366]  ? page_fault+0x1e/0x30
> [  144.138214]  ? __drm_atomic_state_free+0x51/0x60
> [  144.139331]  ? device_del+0x34/0x3a0
> [  144.140197]  platform_device_del.part.14+0x19/0x70
> [  144.141348]  platform_device_unregister+0xe/0x20
> [  144.142458]  vkms_release+0x10/0x30 [vkms]
> [  144.143449]  __drm_atomic_helper_disable_all.constprop.31+0x13b/0x150
> [  144.144980]  drm_atomic_helper_shutdown+0x4b/0x90
> [  144.146102]  vkms_release+0x18/0x30 [vkms]
> [  144.147107]  vkms_exit+0x29/0x8ec [vkms]
> [  144.148053]  __x64_sys_delete_module+0x155/0x220
> [  144.149168]  do_syscall_64+0x43/0x100
> [  144.150056]  entry_SYSCALL_64_after_hwframe+0x5c/0xc1
> 
> It seems that the proper unload sequence is:
> 	drm_atomic_helper_shutdown();
> 	drm_dev_put();
> 
> Just put drm_atomic_helper_shutdown() before drm_dev_put()
> should solve the problem.
> 
> Note that vkms exit code is refactored by 53d77aaa3f76 ("drm/vkms: Use
> devm_drm_dev_alloc") in tags/v5.10-rc1.
> 
> So this bug only exists on 4.19 and 5.4.

Do we also need this for 5.4?  If so, can you send a version for that
tree with the correct Fixes: information, and I will be glad to queue
both of these up.

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH 4.19.y] drm/vkms: call drm_atomic_helper_shutdown before drm_dev_put()
  2024-04-05  9:30 ` Greg KH
@ 2024-04-09  2:38   ` guomengqi (A)
  2024-04-11  7:42     ` Greg KH
  0 siblings, 1 reply; 4+ messages in thread
From: guomengqi (A) @ 2024-04-09  2:38 UTC (permalink / raw)
  To: Greg KH; +Cc: airlied, dri-devel, stable, xuqiang36, zhangchangzhong


在 2024/4/5 17:30, Greg KH 写道:
> On Wed, Apr 03, 2024 at 05:47:16PM +0800, Guo Mengqi wrote:
>> commit 73a82b22963d ("drm/atomic: Fix potential use-after-free
>> in nonblocking commits") introduced drm_dev_get/put() to
>> drm_atomic_helper_shutdown(). And this cause problem in vkms driver exit
>> process.
>>
>> vkms_exit()
>>    drm_dev_put()
>>      vkms_release()
>>        drm_atomic_helper_shutdown()
>>          drm_dev_get()
>>          drm_dev_put()
>>            vkms_release()    ------ null pointer access
>>
>> Using 4.19 stable x86 image on qemu, below stacktrace can be triggered by
>> load and unload vkms.ko.
>>
>> root:~ # insmod vkms.ko
>> [  142.135449] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
>> [  142.138713] [drm] Driver supports precise vblank timestamp query.
>> [  142.142390] [drm] Initialized vkms 1.0.0 20180514 for virtual device on minor 0
>> root:~ # rmmod vkms.ko
>> [  144.093710] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0
>> [  144.097491] PGD 800000023624e067 P4D 800000023624e067 PUD 22ab59067 PMD 0
>> [  144.100802] Oops: 0000 [#1] SMP PTI
>> [  144.102502] CPU: 0 PID: 3615 Comm: rmmod Not tainted 4.19.310 #1
>> [  144.104452] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
>> [  144.107238] RIP: 0010:device_del+0x34/0x3a0
>> ...
>> [  144.131323] Call Trace:
>> [  144.131962]  ? __die+0x7d/0xc0
>> [  144.132711]  ? no_context+0x152/0x3b0
>> [  144.133605]  ? wake_up_q+0x70/0x70
>> [  144.134436]  ? __do_page_fault+0x342/0x4b0
>> [  144.135445]  ? __switch_to_asm+0x41/0x70
>> [  144.136416]  ? __switch_to_asm+0x35/0x70
>> [  144.137366]  ? page_fault+0x1e/0x30
>> [  144.138214]  ? __drm_atomic_state_free+0x51/0x60
>> [  144.139331]  ? device_del+0x34/0x3a0
>> [  144.140197]  platform_device_del.part.14+0x19/0x70
>> [  144.141348]  platform_device_unregister+0xe/0x20
>> [  144.142458]  vkms_release+0x10/0x30 [vkms]
>> [  144.143449]  __drm_atomic_helper_disable_all.constprop.31+0x13b/0x150
>> [  144.144980]  drm_atomic_helper_shutdown+0x4b/0x90
>> [  144.146102]  vkms_release+0x18/0x30 [vkms]
>> [  144.147107]  vkms_exit+0x29/0x8ec [vkms]
>> [  144.148053]  __x64_sys_delete_module+0x155/0x220
>> [  144.149168]  do_syscall_64+0x43/0x100
>> [  144.150056]  entry_SYSCALL_64_after_hwframe+0x5c/0xc1
>>
>> It seems that the proper unload sequence is:
>> 	drm_atomic_helper_shutdown();
>> 	drm_dev_put();
>>
>> Just put drm_atomic_helper_shutdown() before drm_dev_put()
>> should solve the problem.
>>
>> Note that vkms exit code is refactored by 53d77aaa3f76 ("drm/vkms: Use
>> devm_drm_dev_alloc") in tags/v5.10-rc1.
>>
>> So this bug only exists on 4.19 and 5.4.
> Do we also need this for 5.4?  If so, can you send a version for that
> tree with the correct Fixes: information, and I will be glad to queue
> both of these up.

I sent a patch to 5.4.y too. Please check it at 
https://lore.kernel.org/all/20240409022647.1821-1-guomengqi3@huawei.com/T/#u

Thanks,

Mengqi

> thanks,
>
> greg k-h
> .

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH 4.19.y] drm/vkms: call drm_atomic_helper_shutdown before drm_dev_put()
  2024-04-09  2:38   ` guomengqi (A)
@ 2024-04-11  7:42     ` Greg KH
  0 siblings, 0 replies; 4+ messages in thread
From: Greg KH @ 2024-04-11  7:42 UTC (permalink / raw)
  To: guomengqi (A); +Cc: airlied, dri-devel, stable, xuqiang36, zhangchangzhong

On Tue, Apr 09, 2024 at 10:38:34AM +0800, guomengqi (A) wrote:
> 
> 在 2024/4/5 17:30, Greg KH 写道:
> > On Wed, Apr 03, 2024 at 05:47:16PM +0800, Guo Mengqi wrote:
> > > commit 73a82b22963d ("drm/atomic: Fix potential use-after-free
> > > in nonblocking commits") introduced drm_dev_get/put() to
> > > drm_atomic_helper_shutdown(). And this cause problem in vkms driver exit
> > > process.
> > > 
> > > vkms_exit()
> > >    drm_dev_put()
> > >      vkms_release()
> > >        drm_atomic_helper_shutdown()
> > >          drm_dev_get()
> > >          drm_dev_put()
> > >            vkms_release()    ------ null pointer access
> > > 
> > > Using 4.19 stable x86 image on qemu, below stacktrace can be triggered by
> > > load and unload vkms.ko.
> > > 
> > > root:~ # insmod vkms.ko
> > > [  142.135449] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
> > > [  142.138713] [drm] Driver supports precise vblank timestamp query.
> > > [  142.142390] [drm] Initialized vkms 1.0.0 20180514 for virtual device on minor 0
> > > root:~ # rmmod vkms.ko
> > > [  144.093710] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0
> > > [  144.097491] PGD 800000023624e067 P4D 800000023624e067 PUD 22ab59067 PMD 0
> > > [  144.100802] Oops: 0000 [#1] SMP PTI
> > > [  144.102502] CPU: 0 PID: 3615 Comm: rmmod Not tainted 4.19.310 #1
> > > [  144.104452] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
> > > [  144.107238] RIP: 0010:device_del+0x34/0x3a0
> > > ...
> > > [  144.131323] Call Trace:
> > > [  144.131962]  ? __die+0x7d/0xc0
> > > [  144.132711]  ? no_context+0x152/0x3b0
> > > [  144.133605]  ? wake_up_q+0x70/0x70
> > > [  144.134436]  ? __do_page_fault+0x342/0x4b0
> > > [  144.135445]  ? __switch_to_asm+0x41/0x70
> > > [  144.136416]  ? __switch_to_asm+0x35/0x70
> > > [  144.137366]  ? page_fault+0x1e/0x30
> > > [  144.138214]  ? __drm_atomic_state_free+0x51/0x60
> > > [  144.139331]  ? device_del+0x34/0x3a0
> > > [  144.140197]  platform_device_del.part.14+0x19/0x70
> > > [  144.141348]  platform_device_unregister+0xe/0x20
> > > [  144.142458]  vkms_release+0x10/0x30 [vkms]
> > > [  144.143449]  __drm_atomic_helper_disable_all.constprop.31+0x13b/0x150
> > > [  144.144980]  drm_atomic_helper_shutdown+0x4b/0x90
> > > [  144.146102]  vkms_release+0x18/0x30 [vkms]
> > > [  144.147107]  vkms_exit+0x29/0x8ec [vkms]
> > > [  144.148053]  __x64_sys_delete_module+0x155/0x220
> > > [  144.149168]  do_syscall_64+0x43/0x100
> > > [  144.150056]  entry_SYSCALL_64_after_hwframe+0x5c/0xc1
> > > 
> > > It seems that the proper unload sequence is:
> > > 	drm_atomic_helper_shutdown();
> > > 	drm_dev_put();
> > > 
> > > Just put drm_atomic_helper_shutdown() before drm_dev_put()
> > > should solve the problem.
> > > 
> > > Note that vkms exit code is refactored by 53d77aaa3f76 ("drm/vkms: Use
> > > devm_drm_dev_alloc") in tags/v5.10-rc1.
> > > 
> > > So this bug only exists on 4.19 and 5.4.
> > Do we also need this for 5.4?  If so, can you send a version for that
> > tree with the correct Fixes: information, and I will be glad to queue
> > both of these up.
> 
> I sent a patch to 5.4.y too. Please check it at
> https://lore.kernel.org/all/20240409022647.1821-1-guomengqi3@huawei.com/T/#u

Both now queued up, thanks.

greg k-h

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-04-11  7:51 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-04-03  9:47 [PATCH 4.19.y] drm/vkms: call drm_atomic_helper_shutdown before drm_dev_put() Guo Mengqi
2024-04-05  9:30 ` Greg KH
2024-04-09  2:38   ` guomengqi (A)
2024-04-11  7:42     ` Greg KH

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).