From: Yaqi Chen <chendotjs@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
songliubraving@fb.com, yhs@fb.com
Cc: bpf@vger.kernel.org, Yaqi Chen <chendotjs@gmail.com>
Subject: [PATCH bpf] samples/bpf: Fix broken tracex1 due to kprobe argument change
Date: Fri, 16 Apr 2021 23:48:03 +0800 [thread overview]
Message-ID: <20210416154803.37157-1-chendotjs@gmail.com> (raw)
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>
---
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);
--
2.18.4
next reply other threads:[~2021-04-16 15:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-16 15:48 Yaqi Chen [this message]
2021-04-16 17:47 ` [PATCH bpf] samples/bpf: Fix broken tracex1 due to kprobe argument change Yonghong Song
2021-04-20 4:33 ` Andrii Nakryiko
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