| Message ID | 20221101065156.41584-3-yuancan@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/vkms: Fix some memory related bug | expand |
On 11/01, Yuan Can wrote: > 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> > --- > drivers/gpu/drm/vkms/vkms_drv.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c > index dfe983eaa07f..f716c5796f5f 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); Reviewed-by: Melissa Wen <mwen@igalia.com> > } > > static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state) > -- > 2.17.1 >
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c index dfe983eaa07f..f716c5796f5f 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)
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> --- drivers/gpu/drm/vkms/vkms_drv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)