diff options
| author | Yuan Can <yuancan@huawei.com> | 2022-11-01 09:51:56 +0300 |
|---|---|---|
| committer | Melissa Wen <melissa.srw@gmail.com> | 2022-11-30 02:08:49 +0300 |
| commit | 2fe2a8f40c21161ffe7653cc234e7934db5b7cc5 (patch) | |
| tree | c73116047c10beefc185e3619f5b8f31ba2708eb /drivers/gpu/drm/vkms/vkms_drv.c | |
| parent | 0d0b368b9d104b437e1f4850ae94bdb9a3601e89 (diff) | |
| download | linux-2fe2a8f40c21161ffe7653cc234e7934db5b7cc5.tar.xz | |
drm/vkms: Fix null-ptr-deref in vkms_release()
A null-ptr-deref is triggered when it tries to destroy the workqueue in
vkms->output.composer_workq in vkms_release().
KASAN: null-ptr-deref in range [0x0000000000000118-0x000000000000011f]
CPU: 5 PID: 17193 Comm: modprobe Not tainted 6.0.0-11331-gd465bff130bf #24
RIP: 0010:destroy_workqueue+0x2f/0x710
...
Call Trace:
<TASK>
? vkms_config_debugfs_init+0x50/0x50 [vkms]
__devm_drm_dev_alloc+0x15a/0x1c0 [drm]
vkms_init+0x245/0x1000 [vkms]
do_one_initcall+0xd0/0x4f0
do_init_module+0x1a4/0x680
load_module+0x6249/0x7110
__do_sys_finit_module+0x140/0x200
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
The reason is that an OOM happened which triggers the destroy of the
workqueue, however, the workqueue is alloced in the later process,
thus a null-ptr-deref happened. A simple call graph is shown as below:
vkms_init()
vkms_create()
devm_drm_dev_alloc()
__devm_drm_dev_alloc()
devm_drm_dev_init()
devm_add_action_or_reset()
devm_add_action() # an error happened
devm_drm_dev_init_release()
drm_dev_put()
kref_put()
drm_dev_release()
vkms_release()
destroy_workqueue() # null-ptr-deref happened
vkms_modeset_init()
vkms_output_init()
vkms_crtc_init() # where the workqueue get allocated
Fix this by checking if composer_workq is NULL before passing it to
the destroy_workqueue() in vkms_release().
Fixes: 6c234fe37c57 ("drm/vkms: Implement CRC debugfs API")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221101065156.41584-3-yuancan@huawei.com
Diffstat (limited to 'drivers/gpu/drm/vkms/vkms_drv.c')
| -rw-r--r-- | drivers/gpu/drm/vkms/vkms_drv.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c index 8a74f37d5912..69346906ec81 100644 --- a/drivers/gpu/drm/vkms/vkms_drv.c +++ b/drivers/gpu/drm/vkms/vkms_drv.c @@ -57,7 +57,8 @@ static void vkms_release(struct drm_device *dev) { struct vkms_device *vkms = drm_device_to_vkms_device(dev); - destroy_workqueue(vkms->output.composer_workq); + if (vkms->output.composer_workq) + destroy_workqueue(vkms->output.composer_workq); } static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state) |