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#!/usr/bin/env bcc-lua
--[[
Copyright 2016 GitHub, Inc
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
]]
local bpf_source = [[
#include <uapi/linux/ptrace.h>
struct alloc_info_t {
u64 size;
u64 timestamp_ns;
int stack_id;
};
BPF_HASH(sizes, u64);
BPF_HASH(allocs, u64, struct alloc_info_t);
BPF_STACK_TRACE(stack_traces, 10240);
int alloc_enter(struct pt_regs *ctx, size_t size)
{
SIZE_FILTER
if (SAMPLE_EVERY_N > 1) {
u64 ts = bpf_ktime_get_ns();
if (ts % SAMPLE_EVERY_N != 0)
return 0;
}
u64 pid = bpf_get_current_pid_tgid();
u64 size64 = size;
sizes.update(&pid, &size64);
if (SHOULD_PRINT)
bpf_trace_printk("alloc entered, size = %u\n", size);
return 0;
}
int alloc_exit(struct pt_regs *ctx)
{
u64 address = PT_REGS_RC(ctx);
u64 pid = bpf_get_current_pid_tgid();
u64* size64 = sizes.lookup(&pid);
struct alloc_info_t info = {0};
if (size64 == 0)
return 0; // missed alloc entry
info.size = *size64;
sizes.delete(&pid);
info.timestamp_ns = bpf_ktime_get_ns();
info.stack_id = stack_traces.get_stackid(ctx, STACK_FLAGS);
allocs.update(&address, &info);
if (SHOULD_PRINT) {
bpf_trace_printk("alloc exited, size = %lu, result = %lx\n",
info.size, address);
}
return 0;
}
int free_enter(struct pt_regs *ctx, void *address)
{
u64 addr = (u64)address;
struct alloc_info_t *info = allocs.lookup(&addr);
if (info == 0)
return 0;
allocs.delete(&addr);
if (SHOULD_PRINT) {
bpf_trace_printk("free entered, address = %lx, size = %lu\n",
address, info->size);
}
return 0;
}
]]
return function(BPF, utils)
local parser = utils.argparse("memleak", "Catch memory leaks")
parser:flag("-t --trace")
parser:flag("-a --show-allocs")
parser:option("-p --pid"):convert(tonumber)
parser:option("-i --interval", "", 5):convert(tonumber)
parser:option("-o --older", "", 500):convert(tonumber)
parser:option("-s --sample-rate", "", 1):convert(tonumber)
parser:option("-z --min-size", ""):convert(tonumber)
parser:option("-Z --max-size", ""):convert(tonumber)
parser:option("-T --top", "", 10):convert(tonumber)
local args = parser:parse()
local size_filter = ""
if args.min_size and args.max_size then
size_filter = "if (size < %d || size > %d) return 0;" % {args.min_size, args.max_size}
elseif args.min_size then
size_filter = "if (size < %d) return 0;" % args.min_size
elseif args.max_size then
size_filter = "if (size > %d) return 0;" % args.max_size
end
local stack_flags = "0"
if args.pid then
stack_flags = stack_flags .. "|BPF_F_USER_STACK"
end
local text = bpf_source
text = text:gsub("SIZE_FILTER", size_filter)
text = text:gsub("STACK_FLAGS", stack_flags)
text = text:gsub("SHOULD_PRINT", args.trace and "1" or "0")
text = text:gsub("SAMPLE_EVERY_N", tostring(args.sample_rate))
local bpf = BPF:new{text=text, debug=0}
local syms = nil
local min_age_ns = args.older * 1e6
if args.pid then
print("Attaching to malloc and free in pid %d, Ctrl+C to quit." % args.pid)
bpf:attach_uprobe{name="c", sym="malloc", fn_name="alloc_enter", pid=args.pid}
bpf:attach_uprobe{name="c", sym="malloc", fn_name="alloc_exit", pid=args.pid, retprobe=true}
bpf:attach_uprobe{name="c", sym="free", fn_name="free_enter", pid=args.pid}
else
print("Attaching to kmalloc and kfree, Ctrl+C to quit.")
bpf:attach_kprobe{event="__kmalloc", fn_name="alloc_enter"}
bpf:attach_kprobe{event="__kmalloc", fn_name="alloc_exit", retprobe=true} -- TODO
bpf:attach_kprobe{event="kfree", fn_name="free_enter"}
end
local syms = BPF.SymbolCache(args.pid)
local allocs = bpf:get_table("allocs")
local stack_traces = bpf:get_table("stack_traces")
local function resolve(addr)
local sym = syms:resolve(addr)
if args.pid == nil then
sym = sym .. " [kernel]"
end
return string.format("%s (%p)", sym, addr)
end
local function print_outstanding()
local alloc_info = {}
local now = utils.posix.time_ns()
print("[%s] Top %d stacks with outstanding allocations:" %
{os.date("%H:%M:%S"), args.top})
for address, info in allocs:items() do
if now - min_age_ns >= tonumber(info.timestamp_ns) then
local stack_id = tonumber(info.stack_id)
if stack_id >= 0 then
if alloc_info[stack_id] then
local s = alloc_info[stack_id]
s.count = s.count + 1
s.size = s.size + tonumber(info.size)
else
local stack = stack_traces:get(stack_id, resolve)
alloc_info[stack_id] = { stack=stack, count=1, size=tonumber(info.size) }
end
end
if args.show_allocs then
print("\taddr = %p size = %s" % {address, tonumber(info.size)})
end
end
end
local top = table.values(alloc_info)
table.sort(top, function(a, b) return a.size > b.size end)
for n, alloc in ipairs(top) do
print("\t%d bytes in %d allocations from stack\n\t\t%s" %
{alloc.size, alloc.count, table.concat(alloc.stack, "\n\t\t")})
if n == args.top then break end
end
end
if args.trace then
local pipe = bpf:pipe()
while true do
print(pipe:trace_fields())
end
else
while true do
utils.posix.sleep(args.interval)
syms:refresh()
print_outstanding()
end
end
end
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