On Mon, May 11, 2020 at 07:03:06PM -0700, Hemant Kumar wrote:
> Mission mode transition is handled by state worker thread but
> power off is not. There is a possibility while mission mode
> transition is in progress which calls MHI client driver probe,
> power off is issued by MHI controller. This results into client
> driver probe and remove running in parallel and causes use after
> free situation. By queuing disable transition work when mission
> mode is in progress prevents the race condition.
>
> Signed-off-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
> Reviewed-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Thanks,
Mani
> ---
> drivers/bus/mhi/core/init.c | 1 +
> drivers/bus/mhi/core/internal.h | 1 +
> drivers/bus/mhi/core/pm.c | 11 ++++++++++-
> 3 files changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 3a853c5..12207cc 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -35,6 +35,7 @@
> [DEV_ST_TRANSITION_SBL] = "SBL",
> [DEV_ST_TRANSITION_MISSION_MODE] = "MISSION_MODE",
> [DEV_ST_TRANSITION_SYS_ERR] = "SYS_ERR",
> + [DEV_ST_TRANSITION_DISABLE] = "DISABLE",
> };
>
> const char * const mhi_state_str[MHI_STATE_MAX] = {
> diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
> index f01283b..b1f640b 100644
> --- a/drivers/bus/mhi/core/internal.h
> +++ b/drivers/bus/mhi/core/internal.h
> @@ -387,6 +387,7 @@ enum dev_st_transition {
> DEV_ST_TRANSITION_SBL,
> DEV_ST_TRANSITION_MISSION_MODE,
> DEV_ST_TRANSITION_SYS_ERR,
> + DEV_ST_TRANSITION_DISABLE,
> DEV_ST_TRANSITION_MAX,
> };
>
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index d9964d4..345f197 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -657,6 +657,10 @@ void mhi_pm_st_worker(struct work_struct *work)
> mhi_pm_disable_transition
> (mhi_cntrl, MHI_PM_SYS_ERR_PROCESS);
> break;
> + case DEV_ST_TRANSITION_DISABLE:
> + mhi_pm_disable_transition
> + (mhi_cntrl, MHI_PM_SHUTDOWN_PROCESS);
> + break;
> default:
> break;
> }
> @@ -1011,7 +1015,12 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
> to_mhi_pm_state_str(MHI_PM_LD_ERR_FATAL_DETECT),
> to_mhi_pm_state_str(mhi_cntrl->pm_state));
> }
> - mhi_pm_disable_transition(mhi_cntrl, MHI_PM_SHUTDOWN_PROCESS);
> +
> + mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE);
> +
> + /* Wait for shutdown to complete */
> + flush_work(&mhi_cntrl->st_worker);
> +
> mhi_deinit_free_irq(mhi_cntrl);
>
> if (!mhi_cntrl->pre_init) {
> --
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> a Linux Foundation Collaborative Project
