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#!/usr/bin/python
#
# mallocstacks Trace malloc() calls in a process and print the full
# stack trace for all callsites.
# For Linux, uses BCC, eBPF. Embedded C.
#
# This script is a basic example of the new Linux 4.6+ BPF_STACK_TRACE
# table API.
#
# Copyright 2016 GitHub, Inc.
# Licensed under the Apache License, Version 2.0 (the "License")
from __future__ import print_function
from bcc import BPF
from bcc.utils import printb
from time import sleep
import sys
if len(sys.argv) < 2:
print("USAGE: mallocstacks PID [NUM_STACKS=1024]")
exit()
pid = int(sys.argv[1])
if len(sys.argv) == 3:
try:
assert int(sys.argv[2]) > 0, ""
except (ValueError, AssertionError) as e:
print("USAGE: mallocstacks PID [NUM_STACKS=1024]")
print("NUM_STACKS must be a non-zero, positive integer")
exit()
stacks = sys.argv[2]
else:
stacks = "1024"
# load BPF program
b = BPF(text="""
#include <uapi/linux/ptrace.h>
BPF_HASH(calls, int);
BPF_STACK_TRACE(stack_traces, """ + stacks + """);
int alloc_enter(struct pt_regs *ctx, size_t size) {
int key = stack_traces.get_stackid(ctx, BPF_F_USER_STACK);
if (key < 0)
return 0;
// could also use `calls.increment(key, size);`
u64 zero = 0, *val;
val = calls.lookup_or_try_init(&key, &zero);
if (val) {
(*val) += size;
}
return 0;
};
""")
b.attach_uprobe(name="c", sym="malloc", fn_name="alloc_enter", pid=pid)
print("Attaching to malloc in pid %d, Ctrl+C to quit." % pid)
# sleep until Ctrl-C
try:
sleep(99999999)
except KeyboardInterrupt:
pass
calls = b.get_table("calls")
stack_traces = b.get_table("stack_traces")
for k, v in reversed(sorted(calls.items(), key=lambda c: c[1].value)):
print("%d bytes allocated at:" % v.value)
if k.value > 0 :
for addr in stack_traces.walk(k.value):
printb(b"\t%s" % b.sym(addr, pid, show_offset=True))
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