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    Subject[PATCH AUTOSEL 5.10 64/85] samples/bpf: Fix broken tracex1 due to kprobe argument change
    Date
    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
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