[PATCH] cxl/core: Fix cxl_device_lock() class detection

[PATCH] cxl/core: Fix cxl_device_lock() class detection

[Dan Williams]

If cxl_device_lock() is used on a non-CXL device the expectation is that
the lock class will fall back to CXL_ANON_LOCK. Instead it crashes when
trying to determine if the device is a 'decoder'. Specifically when the
device has a NULL type pointer. Just check for NULL before
de-referencing ->release.

Fixes: 3c5b90395525 ("cxl: Prove CXL locking")
Reported-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/core/port.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 9b4bbd51fbaa..d29eb2abdbc2 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -284,7 +284,7 @@ EXPORT_SYMBOL_NS_GPL(is_root_decoder, CXL);
 
 bool is_cxl_decoder(struct device *dev)
 {
-	return dev->type->release == cxl_decoder_release;
+	return dev->type && dev->type->release == cxl_decoder_release;
 }
 EXPORT_SYMBOL_NS_GPL(is_cxl_decoder, CXL);
 

Re: [PATCH] cxl/core: Fix cxl_device_lock() class detection

[Ben Widawsky]

On 22-02-08 23:37:34, Dan Williams wrote:
> If cxl_device_lock() is used on a non-CXL device the expectation is that
> the lock class will fall back to CXL_ANON_LOCK. Instead it crashes when
> trying to determine if the device is a 'decoder'. Specifically when the
> device has a NULL type pointer. Just check for NULL before
> de-referencing ->release.
> 
> Fixes: 3c5b90395525 ("cxl: Prove CXL locking")
> Reported-by: Ben Widawsky <ben.widawsky@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>

> ---
>  drivers/cxl/core/port.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index 9b4bbd51fbaa..d29eb2abdbc2 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -284,7 +284,7 @@ EXPORT_SYMBOL_NS_GPL(is_root_decoder, CXL);
>  
>  bool is_cxl_decoder(struct device *dev)
>  {
> -	return dev->type->release == cxl_decoder_release;
> +	return dev->type && dev->type->release == cxl_decoder_release;
>  }
>  EXPORT_SYMBOL_NS_GPL(is_cxl_decoder, CXL);
>  
>