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authorYaqi Chen <chendotjs@gmail.com>2021-04-16 23:48:03 +0800
committerAlexei Starovoitov <ast@kernel.org>2021-04-19 18:19:49 -0700
commit137733d08f4ab14a354dacaa9a8fc35217747605 (patch)
treedb597015b653b9a2ba76a5d94e296018255761b8 /samples
parent900367b208ee04768bb4323d0051ba11c434bafc (diff)
downloadlinux-137733d08f4ab14a354dacaa9a8fc35217747605.tar.gz
samples/bpf: Fix broken tracex1 due to kprobe argument change
>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
Diffstat (limited to 'samples')
-rw-r--r--samples/bpf/tracex1_kern.c4
1 files 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);