> go version ## golang版本
go version go1.12 linux/amd64
> gdb -v ## gdb版本
GNU gdb (GDB) 8.3
> cat /etc/redhat-release ## centos版本
CentOS Linux release 7.7.1908 (Core)
golang官方是不推荐使用该方式调试golang程序的，因为gdb无法准确的诊断golang运行时的数据结构和表达式，官方文档链接戳这里
我个人使用的过程中也遇见了很多问题，比如说脚本无法加载导致groutine命令无法使用
程序例子
//测试死锁例子
package main
import (
"log"
"net/http"
_ "net/http/pprof"
"os"
"os/signal"
"sync"
"time"
)
func main() {
//启动pprof
go func() {
http.ListenAndServe(":9999", nil)
}()
//模拟死锁
mux := sync.Mutex{}
for j := 0; j < 10; j ++ {
go func(num int) {
for {
mux.Lock()
//defer mux.Unlock()
log.Printf("number %v get lock",num)
if num != 9 {
mux.Unlock()
}
time.Sleep(time.Millisecond*100)
}
}(j)
}
ShutDownHook()
}
// ShutDownHook 关闭勾子事件
func ShutDownHook() {
quit := make(chan os.Signal, 1)
signal.Notify(quit, os.Interrupt, os.Kill)
a := <-quit
log.Println("close ",a)
}
使用gdb诊断运行程序死锁状态
-
运行测试程序
- 源码运行
go run test.go - 二进制运行
禁用函数的内联调用和变量注册，因为这些会使gdb调试更加困难
go build -gcflags=all="-N -l" -o test test.go
- 源码运行
查找出进程id
ps aux|grep test-
查看进程树
> pstree -p <pid> test(12611)-+-{test}(12612) |-{test}(12613) |-{test}(12614) |-{test}(12615) |-{test}(12616) |-{test}(12617) |-{test}(12618) |-{test}(12619)
查看进程堆栈
pstack可以查看出当前进程下所有线程运行的当前栈信息
pstack <pid>-
gdb
- 连接运行的进程
不支持golang的python命令脚本，所以groutine这些没办法调试了> gdb attach <pid> (gdb) ...... warning: Unsupported auto-load script at offset 0 in section .debug_gdb_scripts of file /usr/local/go/bin/go. ...... (gdb) - 查看所有线程当前栈信息
可以查看到当前有8个线程处于锁状态，1一个线程处于epollwait状态，也证明了golang的tcp在centos中使用的是epoll模型(gdb) info threads ##查看所有线程，这个是内核线程，即golang调度器模型中的m，不是协程 Id Target Id Frame * 1 Thread 0x7f8f4fa00740 (LWP 12546) "go" runtime.futex () at /usr/local/go/src/runtime/sys_linux_amd64.s:536 ...... 9 Thread 0x7f8f49686700 (LWP 12554) "go" runtime.epollwait () at /usr/local/go/src/runtime/sys_linux_amd64.s:675- 查看当前线程详细栈
(gdb) info stack 0 runtime.futex () at /usr/local/go/src/runtime/sys_linux_amd64.s:536 1 0x000000000042b41b in runtime.futexsleep (addr=0xe474e8 <runtime.m0+328>, val=0, ns=-1) at /usr/local/go/src/runtime/os_linux.go:46 2 0x000000000040bc71 in runtime.notesleep (n=0xe474e8 <runtime.m0+328>) at /usr/local/go/src/runtime/lock_futex.go:151 3 0x000000000043372c in runtime.stoplockedm () at /usr/local/go/src/runtime/proc.go:2076 4 0x0000000000434f3c in runtime.schedule () at /usr/local/go/src/runtime/proc.go:2477 5 0x00000000004350b1 in runtime.park_m (gp=0xc0000ccf00) at /usr/local/go/src/runtime/proc.go:2605 6 0x000000000045775b in runtime.mcall () at /usr/local/go/src/runtime/asm_amd64.s:299 7 0x0000000000457679 in runtime.rt0_go () at /usr/local/go/src/runtime/asm_amd64.s:201 8 0x0000000000000000 in ?? ()- 切换线程
(gdb) thread 9 [Switching to thread 9 (Thread 0x7f8f49686700 (LWP 12554))] 0 runtime.epollwait () at /usr/local/go/src/runtime/sys_linux_amd64.s:675 675 MOVL AX, ret+24(FP)- 查看线程中运行函数信息
(gdb) info frame 1 Stack frame at 0x7f8f49685d68: rip = 0x42b2d6 in runtime.netpoll (/usr/local/go/src/runtime/netpoll_epoll.go:71); saved rip = 0x4341b5 called by frame at 0x7f8f49685e08, caller of frame at 0x7f8f49685720 source language unknown. Arglist at 0x7f8f49685718, args: block=true, ~r1=... Locals at 0x7f8f49685718, Previous frame is sp is 0x7f8f49685d68 Saved registers: rip at 0x7f8f49685d60
- 连接运行的进程
