From: Colin Ian King <colin.king@canonical.com>
Date: Sun, 29 Aug 2021 19:18:24 +0100
Subject: ceph: fix dereference of null pointer cf
Git-commit: 05a444d3f90a3c3e6362e88a1bf13e1a60f8cace
Patch-mainline: v5.15-rc1
References: bsc#1190451 stable-5.14.6

Currently in the case where kmem_cache_alloc fails the null pointer
cf is dereferenced when assigning cf->is_capsnap = false. Fix this
by adding a null pointer check and return path.

Cc: stable@vger.kernel.org
Addresses-coverity: ("Dereference null return")
Fixes: b2f9fa1f3bd8 ("ceph: correctly handle releasing an embedded cap flush")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>

---
 fs/ceph/caps.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 26c5029629a4..6c0e52fd0743 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1736,6 +1736,9 @@ struct ceph_cap_flush *ceph_alloc_cap_flush(void)
 	struct ceph_cap_flush *cf;
 
 	cf = kmem_cache_alloc(ceph_cap_flush_cachep, GFP_KERNEL);
+	if (!cf)
+		return NULL;
+
 	cf->is_capsnap = false;
 	return cf;
 }