Re: [ndctl PATCH] libcxl: fix a segfault when memdev->pmem is absent

[Alison Schofield <alison.schofield@intel.com>]

On Thu, Jun 02, 2022 at 09:44:27AM -0600, Vishal Verma wrote:
> A CXL memdev may not have any persistent capacity, and in this case it
> is possible that a 'pmem' object never gets instantiated. Such a
> scenario would cause free_pmem () to dereference a NULL pointer and
> segfault.
> 
> Fix this by only proceeding in free_pmem() if 'pmem' was valid.
> 
> Fixes: cd1aed6cefe8 ("libcxl: add representation for an nvdimm bridge object")
> Reported-by: Steven Garcia <steven.garcia@intel.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
> ---

Reviewed-by: Alison Schofield <alison.schofield@intel.com>

>  cxl/lib/libcxl.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c
> index 1ad4a0b..2578a43 100644
> --- a/cxl/lib/libcxl.c
> +++ b/cxl/lib/libcxl.c
> @@ -50,9 +50,11 @@ struct cxl_ctx {
>  
>  static void free_pmem(struct cxl_pmem *pmem)
>  {
> -	free(pmem->dev_buf);
> -	free(pmem->dev_path);
> -	free(pmem);
> +	if (pmem) {
> +		free(pmem->dev_buf);
> +		free(pmem->dev_path);
> +		free(pmem);
> +	}
>  }
>  
>  static void free_memdev(struct cxl_memdev *memdev, struct list_head *head)
> 
> base-commit: 4229f2694e8887a47c636a54130cff0d65f2e995
> -- 
> 2.36.1
> 
>