Re: [PATCH 2/7] cxl/memdev: Hold memdev lock during memdev poison injection/clear

[Dave Jiang]

On 3/10/26 8:57 AM, Li Ming wrote:
> CXL memdev poison injection/clearing debugfs interfaces are visible
> before the CXL memdev endpoint initialization, If user accesses the
> interfaces before cxlmd->endpoint updated, it is possible to access an
> invalid endpoint in cxl_dpa_to_region().
> 
> Hold CXL memdev lock at the beginning of the interfaces, this blocks the
> interfaces until CXL memdev probing completed.
> 
> The following patch will check the given endpoint validity in
> cxl_dpa_to_region().
> 
> Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> Signed-off-by: Li Ming <ming.li@xxxxxxxxxxxx>

Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>

> ---
>  drivers/cxl/core/memdev.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index 273c22118d3d..8ebaf9e96035 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -295,6 +295,7 @@ int cxl_inject_poison_locked(struct cxl_memdev *cxlmd, u64 dpa)
>  	if (!IS_ENABLED(CONFIG_DEBUG_FS))
>  		return 0;
>  
> +	device_lock_assert(&cxlmd->dev);
>  	lockdep_assert_held(&cxl_rwsem.dpa);
>  	lockdep_assert_held(&cxl_rwsem.region);
>  
> @@ -331,6 +332,10 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
>  {
>  	int rc;
>  
> +	ACQUIRE(device_intr, devlock)(&cxlmd->dev);
> +	if ((rc = ACQUIRE_ERR(device_intr, &devlock)))
> +		return rc;
> +
>  	ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region);
>  	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &region_rwsem)))
>  		return rc;
> @@ -355,6 +360,7 @@ int cxl_clear_poison_locked(struct cxl_memdev *cxlmd, u64 dpa)
>  	if (!IS_ENABLED(CONFIG_DEBUG_FS))
>  		return 0;
>  
> +	device_lock_assert(&cxlmd->dev);
>  	lockdep_assert_held(&cxl_rwsem.dpa);
>  	lockdep_assert_held(&cxl_rwsem.region);
>  
> @@ -400,6 +406,10 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
>  {
>  	int rc;
>  
> +	ACQUIRE(device_intr, devlock)(&cxlmd->dev);
> +	if ((rc = ACQUIRE_ERR(device_intr, &devlock)))
> +		return rc;
> +
>  	ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region);
>  	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &region_rwsem)))
>  		return rc;
>