linux-kernel - [PATCH][next] ceph: Fix dereference of null pointer cf

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Date:   Sun, 29 Aug 2021 19:18:24 +0100
From:   Colin King <colin.king@...onical.com>
To:     Jeff Layton <jlayton@...nel.org>,
        Ilya Dryomov <idryomov@...il.com>,
        Xiubo Li <xiubli@...hat.com>, ceph-devel@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] ceph: Fix dereference of null pointer cf

From: Colin Ian King <colin.king@...onical.com>

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.

Addresses-Coverity: ("Dereference null return")
Fixes: b2f9fa1f3bd8 ("ceph: correctly handle releasing an embedded cap flush")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 fs/ceph/caps.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 39db97f149b9..eceb3ceaac48 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1746,6 +1746,8 @@ 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;
 }
-- 
2.32.0