When main component is not probed, by example when the dw-hdmi module is
not loaded yet or in probe defer, the following crash appears on shutdown:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038
...
pc : meson_drv_shutdown+0x24/0x50
lr : platform_drv_shutdown+0x20/0x30
...
Call trace:
meson_drv_shutdown+0x24/0x50
platform_drv_shutdown+0x20/0x30
device_shutdown+0x158/0x360
kernel_restart_prepare+0x38/0x48
kernel_restart+0x18/0x68
__do_sys_reboot+0x224/0x250
__arm64_sys_reboot+0x24/0x30
...
Simply check if the priv struct has been allocated before using it.
Fixes: fa0c16caf3d7 ("drm: meson_drv add shutdown function")
Reported-by: Stefan Agner <[email protected]>
Signed-off-by: Neil Armstrong <[email protected]>
---
drivers/gpu/drm/meson/meson_drv.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 453d8b4c5763..07fcd12dca16 100644
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -485,11 +485,12 @@ static int meson_probe_remote(struct platform_device *pdev,
static void meson_drv_shutdown(struct platform_device *pdev)
{
struct meson_drm *priv = dev_get_drvdata(&pdev->dev);
- struct drm_device *drm = priv->drm;
- DRM_DEBUG_DRIVER("\n");
- drm_kms_helper_poll_fini(drm);
- drm_atomic_helper_shutdown(drm);
+ if (!priv)
+ return;
+
+ drm_kms_helper_poll_fini(priv->drm);
+ drm_atomic_helper_shutdown(priv->drm);
}
static int meson_drv_probe(struct platform_device *pdev)
--
2.25.1
On Fri, Apr 30, 2021 at 10:28 AM Neil Armstrong <[email protected]> wrote:
>
> When main component is not probed, by example when the dw-hdmi module is
> not loaded yet or in probe defer, the following crash appears on shutdown:
>
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038
> ...
> pc : meson_drv_shutdown+0x24/0x50
> lr : platform_drv_shutdown+0x20/0x30
> ...
> Call trace:
> meson_drv_shutdown+0x24/0x50
> platform_drv_shutdown+0x20/0x30
> device_shutdown+0x158/0x360
> kernel_restart_prepare+0x38/0x48
> kernel_restart+0x18/0x68
> __do_sys_reboot+0x224/0x250
> __arm64_sys_reboot+0x24/0x30
> ...
>
> Simply check if the priv struct has been allocated before using it.
>
> Fixes: fa0c16caf3d7 ("drm: meson_drv add shutdown function")
> Reported-by: Stefan Agner <[email protected]>
> Signed-off-by: Neil Armstrong <[email protected]>
Tested-by: Martin Blumenstingl <[email protected]>
Hi Neil,
since this has not received any Reviewed-by yet I tried my best to
review it myself
On Fri, Apr 30, 2021 at 10:28 AM Neil Armstrong <[email protected]> wrote:
[...]
> --- a/drivers/gpu/drm/meson/meson_drv.c
> +++ b/drivers/gpu/drm/meson/meson_drv.c
> @@ -485,11 +485,12 @@ static int meson_probe_remote(struct platform_device *pdev,
> static void meson_drv_shutdown(struct platform_device *pdev)
> {
> struct meson_drm *priv = dev_get_drvdata(&pdev->dev);
this part made it hard for me because I was wondering where the
matching dev_set_drvdata call is
it turns out platform_set_drvdata is used instead, meaning for me it
would have been easier to understand if platform_get_drvdata was used
here
that's however nothing which has changed with this patch
> - struct drm_device *drm = priv->drm;
>
> - DRM_DEBUG_DRIVER("\n");
> - drm_kms_helper_poll_fini(drm);
> - drm_atomic_helper_shutdown(drm);
> + if (!priv)
> + return;
> +
> + drm_kms_helper_poll_fini(priv->drm);
> + drm_atomic_helper_shutdown(priv->drm);
> }
then this part finally made sense to me (as non-drm person), as
platform_set_drvdata comes near the end of meson_drv_bind_master (so
any errors would cause the drvdata to be NULL).
with this I can also give me:
Reviewed-by: Martin Blumenstingl <[email protected]>
in addition to my:
Tested-by: Martin Blumenstingl <[email protected]>
Can you please queue this up for -fixes or do we need to ask someone to do it?
Best regards,
Martin
Hi Martin,
On 20/05/2021 22:25, Martin Blumenstingl wrote:
> Hi Neil,
>
> since this has not received any Reviewed-by yet I tried my best to
> review it myself
>
> On Fri, Apr 30, 2021 at 10:28 AM Neil Armstrong <[email protected]> wrote:
> [...]
>> --- a/drivers/gpu/drm/meson/meson_drv.c
>> +++ b/drivers/gpu/drm/meson/meson_drv.c
>> @@ -485,11 +485,12 @@ static int meson_probe_remote(struct platform_device *pdev,
>> static void meson_drv_shutdown(struct platform_device *pdev)
>> {
>> struct meson_drm *priv = dev_get_drvdata(&pdev->dev);
> this part made it hard for me because I was wondering where the
> matching dev_set_drvdata call is
> it turns out platform_set_drvdata is used instead, meaning for me it
> would have been easier to understand if platform_get_drvdata was used
> here
> that's however nothing which has changed with this patch
OK sure, indeed, but since it's the same... but yeah it may be an issue if platform_set_drvdata changes.
>
>> - struct drm_device *drm = priv->drm;
>>
>> - DRM_DEBUG_DRIVER("\n");
>> - drm_kms_helper_poll_fini(drm);
>> - drm_atomic_helper_shutdown(drm);
>> + if (!priv)
>> + return;
>> +
>> + drm_kms_helper_poll_fini(priv->drm);
>> + drm_atomic_helper_shutdown(priv->drm);
>> }
> then this part finally made sense to me (as non-drm person), as
> platform_set_drvdata comes near the end of meson_drv_bind_master (so
> any errors would cause the drvdata to be NULL).
>
> with this I can also give me:
> Reviewed-by: Martin Blumenstingl <[email protected]>
> in addition to my:
> Tested-by: Martin Blumenstingl <[email protected]>
Thanks !
>
> Can you please queue this up for -fixes or do we need to ask someone to do it?
Yes, the drm-misc-next & drm-misc-fixes are aleays opened and merged each week in the corresponding drm-next and drm-fixes
branches, so we can push patches at anytime without thinking about the merge window (except drm-misc-fixes merged back with -rc1).
Neil
>
>
> Best regards,
> Martin
>
On 30/04/2021 10:27, Neil Armstrong wrote:
> When main component is not probed, by example when the dw-hdmi module is
> not loaded yet or in probe defer, the following crash appears on shutdown:
>
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038
> ...
> pc : meson_drv_shutdown+0x24/0x50
> lr : platform_drv_shutdown+0x20/0x30
> ...
> Call trace:
> meson_drv_shutdown+0x24/0x50
> platform_drv_shutdown+0x20/0x30
> device_shutdown+0x158/0x360
> kernel_restart_prepare+0x38/0x48
> kernel_restart+0x18/0x68
> __do_sys_reboot+0x224/0x250
> __arm64_sys_reboot+0x24/0x30
> ...
>
> Simply check if the priv struct has been allocated before using it.
>
> Fixes: fa0c16caf3d7 ("drm: meson_drv add shutdown function")
> Reported-by: Stefan Agner <[email protected]>
> Signed-off-by: Neil Armstrong <[email protected]>
> ---
> drivers/gpu/drm/meson/meson_drv.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
> index 453d8b4c5763..07fcd12dca16 100644
> --- a/drivers/gpu/drm/meson/meson_drv.c
> +++ b/drivers/gpu/drm/meson/meson_drv.c
> @@ -485,11 +485,12 @@ static int meson_probe_remote(struct platform_device *pdev,
> static void meson_drv_shutdown(struct platform_device *pdev)
> {
> struct meson_drm *priv = dev_get_drvdata(&pdev->dev);
> - struct drm_device *drm = priv->drm;
>
> - DRM_DEBUG_DRIVER("\n");
> - drm_kms_helper_poll_fini(drm);
> - drm_atomic_helper_shutdown(drm);
> + if (!priv)
> + return;
> +
> + drm_kms_helper_poll_fini(priv->drm);
> + drm_atomic_helper_shutdown(priv->drm);
> }
>
> static int meson_drv_probe(struct platform_device *pdev)
>
Applied to drm-misc-fixes
Neil