main.bt

#!/usr/bin/env bpftrace

#include <linux/netdevice.h>
#include <linux/skbuff.h>

tracepoint:skb:kfree_skb {
    $skb = (struct sk_buff *)args->skbaddr;

    if ($skb->mark == 0x23456) {
        printf("------------------------------------------------------------\n");
        printf("$skb = %p\n", $skb);
        printf("$skb->dev->name = %s\n", $skb->dev->name);
        printf("$skb->mark = 0x%x\n", $skb->mark);
        printf("stacktrace: %s", kstack());
    }
}