Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Roman Gushchin <guro@fb.com>
To:     <netdev@vger.kernel.org>
CC:     <linux-kernel@vger.kernel.org>, <kernel-team@fb.com>,
        Roman Gushchin <guro@fb.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH v2 bpf 4/5] bpf: add missing rcu_dereference() in bpf_prog_array_delete_safe()
Date:   Fri, 13 Jul 2018 12:41:13 -0700
Message-ID: <20180713194114.2711-4-guro@fb.com>
In-Reply-To: <20180713194114.2711-1-guro@fb.com>
References: <20180713194114.2711-1-guro@fb.com>
MIME-Version: 1.0
Content-Type: text/plain
Received-SPF: None (protection.outlook.com: fb.com does not designate
 permitted sender hosts)
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Jul 2018 19:41:32.3875 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 1bef757c-6858-4b07-2bc6-08d5e8f8a33d
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1PR15MB0171
X-OriginatorOrg: fb.com
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-07-13_07:,,
 signatures=0
X-Proofpoint-Spam-Reason: safe
X-FB-Internal: Safe
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

There is a missing rcu_dereference() in bpf_prog_array_delete_safe().
The progs argument is a __rcu pointer, so dereferencing should be
performed using rcu_dereference(), as, for example, in
bpf_prog_array_length().

This patch helps to remove the following sparse warning:
kernel/bpf/core.c:1629:34: warning: incorrect type in initializer (different address spaces)

Fixes: 324bda9e6c5a ("bpf: multi program support for cgroup+bpf")
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
---
 kernel/bpf/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index fdf961f70deb..722ae6913dc0 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1625,7 +1625,7 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,
 void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs,
 				struct bpf_prog *old_prog)
 {
-	struct bpf_prog **prog = progs->progs;
+	struct bpf_prog **prog = rcu_dereference(progs)->progs;
 
 	for (; *prog; prog++)
 		if (*prog == old_prog) {
-- 
2.14.4