[PATCH v2] mmc: mxs: Initialize the spinlock prior to using it

[PATCH v2] mmc: mxs: Initialize the spinlock prior to using it

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam@nxp.com>

An interrupt may occur right after devm_request_irq() is called and
prior to the spinlock initialization, leading to a kernel oops,
as the interrupt handler uses the spinlock.

In order to prevent this problem, move the spinlock initialization 
prior to requesting the interrupts.

Cc: <stable@vger.kernel.org>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Marek Vasut <marex@denx.de>
---
Changes since v1:
- Make it a standalone patch instead of patch series
- Cc stable as suggested by Stefan

 drivers/mmc/host/mxs-mmc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/mxs-mmc.c b/drivers/mmc/host/mxs-mmc.c
index d839147..44ecebd 100644
--- a/drivers/mmc/host/mxs-mmc.c
+++ b/drivers/mmc/host/mxs-mmc.c
@@ -661,13 +661,13 @@ static int mxs_mmc_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, mmc);
 
+	spin_lock_init(&host->lock);
+
 	ret = devm_request_irq(&pdev->dev, irq_err, mxs_mmc_irq_handler, 0,
 			       dev_name(&pdev->dev), host);
 	if (ret)
 		goto out_free_dma;
 
-	spin_lock_init(&host->lock);
-
 	ret = mmc_add_host(mmc);
 	if (ret)
 		goto out_free_dma;
-- 
2.7.4

Re: [PATCH v2] mmc: mxs: Initialize the spinlock prior to using it

[Stefan Wahren]

Hi Fabio,

> Fabio Estevam <festevam@gmail.com> hat am 5. November 2016 um 20:23
> geschrieben:
> 
> 
> From: Fabio Estevam <fabio.estevam@nxp.com>
> 
> An interrupt may occur right after devm_request_irq() is called and
> prior to the spinlock initialization, leading to a kernel oops,
> as the interrupt handler uses the spinlock.
> 
> In order to prevent this problem, move the spinlock initialization 
> prior to requesting the interrupts.
> 
> Cc: <stable@vger.kernel.org>

my intention was to add something like this:

Fixes: e4243f13d10e (mmc: mxs-mmc: add mmc host driver for i.MX23/28)

because it's a bugfix. I wasn't absolutly sure it's a stable candidate.

Thanks
Stefan

> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
> Reviewed-by: Marek Vasut <marex@denx.de>
> ---
> Changes since v1:
> - Make it a standalone patch instead of patch series
> - Cc stable as suggested by Stefan
> 
>  drivers/mmc/host/mxs-mmc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/host/mxs-mmc.c b/drivers/mmc/host/mxs-mmc.c
> index d839147..44ecebd 100644
> --- a/drivers/mmc/host/mxs-mmc.c
> +++ b/drivers/mmc/host/mxs-mmc.c
> @@ -661,13 +661,13 @@ static int mxs_mmc_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, mmc);
>  
> +	spin_lock_init(&host->lock);
> +
>  	ret = devm_request_irq(&pdev->dev, irq_err, mxs_mmc_irq_handler, 0,
>  			       dev_name(&pdev->dev), host);
>  	if (ret)
>  		goto out_free_dma;
>  
> -	spin_lock_init(&host->lock);
> -
>  	ret = mmc_add_host(mmc);
>  	if (ret)
>  		goto out_free_dma;
> -- 
> 2.7.4
>