From: Shixiong Ou <oushixiong@xxxxxxxxxx>
If Calling hibmc_mm_init() failed in hibmc_load(), the hibmc_unload()
will access a NULL pointer, as it don't call ww_mutex_init() to
initialize mode_config.connection_mutex but try to lock it when
calling drm_atomic_helper_shutdown().
[ 50.939211][ 0] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018
......
[ 51.149882][ 0] Call trace:
[ 51.152750][ 0] ww_mutex_lock+0xf0/0x1e0
[ 51.156829][ 0] drm_modeset_lock+0x184/0x2c0
[ 51.161254][ 0] drm_modeset_lock_all_ctx+0x98/0x188
[ 51.166284][ 0] drm_atomic_helper_shutdown+0xa4/0x128
[ 51.171487][ 0] hibmc_unload+0x50/0x2f0
[ 51.175479][ 0] hibmc_load+0x5d8/0x888
[ 51.179386][ 0] drm_dev_register+0x280/0x558
[ 51.183811][ 0] drm_get_pci_dev+0x140/0x3c8
[ 51.188150][ 0] hibmc_pci_probe+0x148/0x190
[ 51.192489][ 0] local_pci_probe+0xc4/0x180
[ 51.196742][ 0] pci_device_probe+0x328/0x530
[ 51.201167][ 0] really_probe+0x498/0x9a0
[ 51.205248][ 0] driver_probe_device+0x224/0x308
[ 51.209932][ 0] device_driver_attach+0xec/0x128
[ 51.214616][ 0] __driver_attach+0x144/0x280
[ 51.218955][ 0] bus_for_each_dev+0x120/0x1a0
[ 51.223380][ 0] driver_attach+0x48/0x60
[ 51.227372][ 0] bus_add_driver+0x328/0x578
[ 51.231625][ 0] driver_register+0x148/0x398
[ 51.235965][ 0] __pci_register_driver+0x15c/0x1c8
[ 51.240823][ 0] hibmc_init+0x2c/0x34
[ 51.244557][ 0] do_one_initcall+0xc8/0x4a8
[ 51.248810][ 0] kernel_init_freeable+0x678/0x75c
[ 51.253582][ 0] kernel_init+0x18/0x128
[ 51.257489][ 0] ret_from_fork+0x10/0x18
Add a initialized flag to avoid this.
Signed-off-by: Shixiong Ou <oushixiong@xxxxxxxxxx>
---
drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 8 ++++++--
drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h | 1 +
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
index 57c21ec452b7..343f64d66e75 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
@@ -99,6 +99,7 @@ static int hibmc_kms_init(struct hibmc_drm_private *priv)
ret = drmm_mode_config_init(dev);
if (ret)
return ret;
+ priv->mode_config_initialized = true;
dev->mode_config.min_width = 0;
dev->mode_config.min_height = 0;
@@ -240,9 +241,12 @@ static int hibmc_hw_init(struct hibmc_drm_private *priv)
static int hibmc_unload(struct drm_device *dev)
{
struct pci_dev *pdev = to_pci_dev(dev->dev);
+ struct hibmc_drm_private *priv = to_hibmc_drm_private(dev);
- drm_atomic_helper_shutdown(dev);
-
+ if(priv->mode_config_initialized){
+ drm_atomic_helper_shutdown(dev);
+ priv->mode_config_initialized = false;
+ }
free_irq(pdev->irq, dev);
pci_disable_msi(to_pci_dev(dev->dev));
diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
index 207aa3f660b0..08fd7cb59bb5 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.h
@@ -37,6 +37,7 @@ struct hibmc_drm_private {
struct drm_crtc crtc;
struct drm_encoder encoder;
struct hibmc_connector connector;
+ bool mode_config_initialized;
};
static inline struct hibmc_connector *to_hibmc_connector(struct drm_connector *connector)
--
2.25.1
