Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yaqi Chen <chendotjs@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Yonghong Song <yhs@fb.com>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.12 100/363] samples/bpf: Fix broken tracex1 due to kprobe argument change
Date:   Mon, 17 May 2021 15:59:26 +0200
Message-Id: <20210517140305.967244875@linuxfoundation.org>
In-Reply-To: <20210517140302.508966430@linuxfoundation.org>
References: <20210517140302.508966430@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Yaqi Chen <chendotjs@gmail.com>

[ Upstream commit 137733d08f4ab14a354dacaa9a8fc35217747605 ]

>From commit c0bbbdc32feb ("__netif_receive_skb_core: pass skb by
reference"), the first argument passed into __netif_receive_skb_core
has changed to reference of a skb pointer.

This commit fixes by using bpf_probe_read_kernel.

Signed-off-by: Yaqi Chen <chendotjs@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210416154803.37157-1-chendotjs@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 samples/bpf/tracex1_kern.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/samples/bpf/tracex1_kern.c b/samples/bpf/tracex1_kern.c
index 3f4599c9a202..ef30d2b353b0 100644
--- a/samples/bpf/tracex1_kern.c
+++ b/samples/bpf/tracex1_kern.c
@@ -26,7 +26,7 @@
 SEC("kprobe/__netif_receive_skb_core")
 int bpf_prog1(struct pt_regs *ctx)
 {
-	/* attaches to kprobe netif_receive_skb,
+	/* attaches to kprobe __netif_receive_skb_core,
 	 * looks for packets on loobpack device and prints them
 	 */
 	char devname[IFNAMSIZ];
@@ -35,7 +35,7 @@ int bpf_prog1(struct pt_regs *ctx)
 	int len;
 
 	/* non-portable! works for the given kernel only */
-	skb = (struct sk_buff *) PT_REGS_PARM1(ctx);
+	bpf_probe_read_kernel(&skb, sizeof(skb), (void *)PT_REGS_PARM1(ctx));
 	dev = _(skb->dev);
 	len = _(skb->len);
 
-- 
2.30.2