We cannot process a power_down if the power state is DISABLED. There is
no valid mhi_ctxt in that case, so attepting to process the power_down
will likely result in a null pointer dereference. If the power state is
DISABLED, there is nothing to do anyways, so just bail early.
Signed-off-by: Jeffrey Hugo <[email protected]>
---
drivers/bus/mhi/core/pm.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index 56ba3ab..dc69074 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -1144,6 +1144,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
mhi_deinit_dev_ctxt(mhi_cntrl);
error_dev_ctxt:
+ mhi_cntrl->pm_state = MHI_PM_DISABLE;
mutex_unlock(&mhi_cntrl->pm_mutex);
return ret;
@@ -1155,6 +1156,12 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
enum mhi_pm_state cur_state, transition_state;
struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ mutex_lock(&mhi_cntrl->pm_mutex);
+ cur_state = mhi_cntrl->pm_state;
+ mutex_unlock(&mhi_cntrl->pm_mutex);
+ if (cur_state == MHI_PM_DISABLE)
+ return; /* Already powered down */
+
/* If it's not a graceful shutdown, force MHI to linkdown state */
transition_state = (graceful) ? MHI_PM_SHUTDOWN_PROCESS :
MHI_PM_LD_ERR_FATAL_DETECT;
--
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
On 2021-02-16 01:38 PM, Jeffrey Hugo wrote:
> We cannot process a power_down if the power state is DISABLED. There
> is
> no valid mhi_ctxt in that case, so attepting to process the power_down
> will likely result in a null pointer dereference. If the power state
> is
> DISABLED, there is nothing to do anyways, so just bail early.
>
> Signed-off-by: Jeffrey Hugo <[email protected]>
> ---
> drivers/bus/mhi/core/pm.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index 56ba3ab..dc69074 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -1144,6 +1144,7 @@ int mhi_async_power_up(struct mhi_controller
> *mhi_cntrl)
> mhi_deinit_dev_ctxt(mhi_cntrl);
>
> error_dev_ctxt:
> + mhi_cntrl->pm_state = MHI_PM_DISABLE;
> mutex_unlock(&mhi_cntrl->pm_mutex);
>
> return ret;
> @@ -1155,6 +1156,12 @@ void mhi_power_down(struct mhi_controller
> *mhi_cntrl, bool graceful)
> enum mhi_pm_state cur_state, transition_state;
> struct device *dev = &mhi_cntrl->mhi_dev->dev;
>
> + mutex_lock(&mhi_cntrl->pm_mutex);
> + cur_state = mhi_cntrl->pm_state;
> + mutex_unlock(&mhi_cntrl->pm_mutex);
> + if (cur_state == MHI_PM_DISABLE)
Let's unlock the mutex here and not at the top. We acquire it below
anyway.
> + return; /* Already powered down */
> +
> /* If it's not a graceful shutdown, force MHI to linkdown state */
> transition_state = (graceful) ? MHI_PM_SHUTDOWN_PROCESS :
> MHI_PM_LD_ERR_FATAL_DETECT;
Thanks,
Bhaumik
---
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
Forum,
a Linux Foundation Collaborative Project
On Tue, Feb 16, 2021 at 02:38:16PM -0700, Jeffrey Hugo wrote:
> We cannot process a power_down if the power state is DISABLED. There is
> no valid mhi_ctxt in that case, so attepting to process the power_down
> will likely result in a null pointer dereference. If the power state is
> DISABLED, there is nothing to do anyways, so just bail early.
>
> Signed-off-by: Jeffrey Hugo <[email protected]>
> ---
> drivers/bus/mhi/core/pm.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index 56ba3ab..dc69074 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -1144,6 +1144,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
> mhi_deinit_dev_ctxt(mhi_cntrl);
>
> error_dev_ctxt:
> + mhi_cntrl->pm_state = MHI_PM_DISABLE;
> mutex_unlock(&mhi_cntrl->pm_mutex);
pm_lock is supposed to protect the PM state. The current code needs a cleanup
interms of locking. It's been on my TODO list for sometime...
>
> return ret;
> @@ -1155,6 +1156,12 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
> enum mhi_pm_state cur_state, transition_state;
> struct device *dev = &mhi_cntrl->mhi_dev->dev;
>
> + mutex_lock(&mhi_cntrl->pm_mutex);
> + cur_state = mhi_cntrl->pm_state;
> + mutex_unlock(&mhi_cntrl->pm_mutex);
Same here.
Thanks,
Mani
> + if (cur_state == MHI_PM_DISABLE)
> + return; /* Already powered down */
> +
> /* If it's not a graceful shutdown, force MHI to linkdown state */
> transition_state = (graceful) ? MHI_PM_SHUTDOWN_PROCESS :
> MHI_PM_LD_ERR_FATAL_DETECT;
> --
> Qualcomm Technologies, Inc. is a member of the
> Code Aurora Forum, a Linux Foundation Collaborative Project.
>