2021-01-08 20:58:17

by Bhaumik Bhatt

Subject: [PATCH v5 9/9] bus: mhi: core: Do not clear channel context more than once

When clearing the channel context, calling mhi_free_coherent()
more than once can result in kernel warnings such as "trying to
free invalid coherent area". Prevent extra work by adding a check
to skip calling mhi_deinit_chan_ctxt() if the client driver has
already disabled the channels.

Signed-off-by: Bhaumik Bhatt <[email protected]>
---
drivers/bus/mhi/core/init.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 30eef19..272f350 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -1314,6 +1314,7 @@ static int mhi_driver_remove(struct device *dev)

if ((ch_state[dir] == MHI_CH_STATE_ENABLED ||
ch_state[dir] == MHI_CH_STATE_STOP) &&
+ mhi_chan->ch_state != MHI_CH_STATE_DISABLED &&
!mhi_chan->offload_ch)
mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);

--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

2021-01-09 04:42:55

by Hemant Kumar

Subject: Re: [PATCH v5 9/9] bus: mhi: core: Do not clear channel context more than once

On 1/8/21 12:54 PM, Bhaumik Bhatt wrote:
> When clearing the channel context, calling mhi_free_coherent()
> more than once can result in kernel warnings such as "trying to
> free invalid coherent area". Prevent extra work by adding a check
> to skip calling mhi_deinit_chan_ctxt() if the client driver has
> already disabled the channels.
>
> Signed-off-by: Bhaumik Bhatt <[email protected]>
> ---
> drivers/bus/mhi/core/init.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 30eef19..272f350 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -1314,6 +1314,7 @@ static int mhi_driver_remove(struct device *dev)
>
> if ((ch_state[dir] == MHI_CH_STATE_ENABLED ||
> ch_state[dir] == MHI_CH_STATE_STOP) &&
> + mhi_chan->ch_state != MHI_CH_STATE_DISABLED &&
> !mhi_chan->offload_ch)
> mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
>
>
Reviewed-by: Hemant Kumar <[email protected]>
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

2021-01-21 15:22:28

by Manivannan Sadhasivam

Subject: Re: [PATCH v5 9/9] bus: mhi: core: Do not clear channel context more than once

On Fri, Jan 08, 2021 at 12:54:57PM -0800, Bhaumik Bhatt wrote:
> When clearing the channel context, calling mhi_free_coherent()
> more than once can result in kernel warnings such as "trying to
> free invalid coherent area". Prevent extra work by adding a check
> to skip calling mhi_deinit_chan_ctxt() if the client driver has
> already disabled the channels.
>

Again, please explain where and when exactly you spotted this issue.

Thanks,
Mani

> Signed-off-by: Bhaumik Bhatt <[email protected]>
> ---
> drivers/bus/mhi/core/init.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 30eef19..272f350 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -1314,6 +1314,7 @@ static int mhi_driver_remove(struct device *dev)
>
> if ((ch_state[dir] == MHI_CH_STATE_ENABLED ||
> ch_state[dir] == MHI_CH_STATE_STOP) &&
> + mhi_chan->ch_state != MHI_CH_STATE_DISABLED &&
> !mhi_chan->offload_ch)
> mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
>
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>