From 50e7a021314aa0365c9c85a359a31f26313fe93b Mon Sep 17 00:00:00 2001
From: Vishal Verma <vishal.l.verma@intel.com>
Date: Thu, 2 Jun 2022 09:44:27 -0600
Subject: [PATCH 171/217] libcxl: fix a segfault when memdev->pmem is absent

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.

Link: https://lore.kernel.org/r/20220602154427.462852-1-vishal.l.verma@intel.com
Fixes: cd1aed6cefe8 ("libcxl: add representation for an nvdimm bridge object")
Cc: Dan Williams <dan.j.williams@intel.com>
Reported-by: Steven Garcia <steven.garcia@intel.com>
Tested-by: Steven Garcia <steven.garcia@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@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 374b0f1..c988ce2 100644
--- a/cxl/lib/libcxl.c
+++ b/cxl/lib/libcxl.c
@@ -49,9 +49,11 @@ 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)
-- 
2.27.0