gcBgMarkStartWorkers引发无法正常运行的gc并导致nginx无响应

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$ go version
go version go1.19 linux/amd64
$ go env
go env
go111module="on"
goarch="amd64"
gobin=""
gocache="/root/.cache/go-build"
goenv="/root/.config/go/env"
goexe=""
goexperiment=""
goflags=""
gohostarch="amd64"
gohostos="linux"
goinsecure=""
gomodcache="/root/go/pkg/mod"
gonoproxy="*.qianxin-inc.cn"
gonosumdb="*.qianxin-inc.cn"
goos="linux"
gopath="/root/go"
goprivate="*.qianxin-inc.cn"
goproxy="https://goproxy.cn,direct"
goroot="/root/go"
gosumdb="sum.golang.org"
gotmpdir=""
gotooldir="/root/go/pkg/tool/linux_amd64"
govcs=""
goversion="go1.19"
gccgo="gccgo"
goamd64="v1"
ar="ar"
cc="gcc"
cxx="g++"
cgo_enabled="1"
gomod="/dev/null"
gowork=""
cgo_cflags="-g -o2"
cgo_cppflags=""
cgo_cxxflags="-g -o2"
cgo_fflags="-g -o2"
cgo_ldflags="-g -o2"
pkg_config="pkg-config"
gogccflags="-fpic -m64 -pthread -wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build273339992=/tmp/go-build -gno-record-gcc-switches"

我的程序抛出一些错误，但我无法解决。

它是用c编写的，而一些函数是用go编写的。

我使用 `go build -o libtest.so -buildmode=c-shared xxx.go xxx.go;``

执行命令后，得到一个libtest.so，然后在c程序中通过dlopen调用它。

我的 c 程序作为 nginx 中的插件运行。

调用go函数后，nginx没有任何响应。我使用gdb对其进行调试，并发现以下回溯：

(gdb) bt
#0 runtime.futex () at /usr/local/go/src/runtime/sys_linux_amd64.s:520
#1 0x00007fff23c550f6 in runtime.futexsleep (addr=0xfffffffffffffe00, val=0, ns=140733793710979) at /usr/local/go/src/runtime/os_linux.go:44
#2 0x00007fff23c35667 in runtime.notetsleep_internal (n=0x7fff23dc66e8 <runtime.work+232>, ns=-1) at /usr/local/go/src/runtime/lock_futex.go:183
#3 0x00007fff23c35785 in runtime.notetsleepg (n=0x7fff23dc66e8 <runtime.work+232>, ns=-1) at /usr/local/go/src/runtime/lock_futex.go:237
#4 0x00007fff23c41338 in runtime.gcBgMarkStartWorkers () at /usr/local/go/src/runtime/mgc.go:1126
#5 0x00007fff23c3fd92 in runtime.gcStart (trigger=...) at /usr/local/go/src/runtime/mgc.go:637
#6 0x00007fff23c36e3d in runtime.mallocgc (size=565248, typ=0x7fff23cfd160, needzero=true) at /usr/local/go/src/runtime/malloc.go:1174
#7 0x00007fff23c6dfaa in runtime.growslice (et=, old=..., cap=) at /usr/local/go/src/runtime/slice.go:267
#8 0x00007fff23c918ef in regexp/syntax.(*compiler).inst (c=0xc000044bf8, op=) at /usr/local/go/src/regexp/syntax/compile.go:164
#9 regexp/syntax.(*compiler).rune (c=0xc000044bf8, r=[]int32 = {...}, flags=212) at /usr/local/go/src/regexp/syntax/compile.go:273
#10 0x00007fff23c90f1e in regexp/syntax.(*compiler).compile (c=0xc000044bf8, re=0xc000190000) at /usr/local/go/src/regexp/syntax/compile.go:101
#11 0x00007fff23c8f805 in regexp/syntax.Compile (re=0xc000190000) at /usr/local/go/src/regexp/syntax/compile.go:74
#12 0x00007fff23ca4a9a in regexp.compile (expr=,
mode=, longest=false) at /usr/local/go/src/regexp/regexp.go:178
#13 0x00007fff23ca5591 in regexp.Compile (expr="") at /usr/local/go/src/regexp/regexp.go:133
#14 regexp.MustCompile (str="") at /usr/local/go/src/regexp/regexp.go:309
#15 0x00007fff23ca8e0a in main.CheckPostAddress (buf=, bufLen=) at /root/codes/di_rechk/rechk.go:540
#16 0x00007fff23ca9a88 in _cgoexp_67df0785bef2_CheckPostAddress (a=0x7fffffffc740) at _cgo_gotypes.go:162
#17 0x00007fff23c2e21a in runtime.cgocallbackg1 (fn=0x7fff23ca9a60 <_cgoexp_67df0785bef2_CheckPostAddress>, frame=0x7fffffffc740, ctxt=0)
at /usr/local/go/src/runtime/cgocall.go:306
#18 0x00007fff23c2dee9 in runtime.cgocallbackg (fn=0x7fff23ca9a60 <_cgoexp_67df0785bef2_CheckPostAddress>, frame=0x7fffffffc740, ctxt=0)
at /usr/local/go/src/runtime/cgocall.go:232
#19 0x00007fff23c83791 in runtime.cgocallbackg (fn=0x7fff23ca9a60 <_cgoexp_67df0785bef2_CheckPostAddress>, frame=0x7fffffffc740, ctxt=0)
at :1
#20 0x00007fff23c813f3 in runtime.cgocallback () at /usr/local/go/src/runtime/asm_amd64.s:915
#21 0x00007fff23c81601 in runtime.goexit () at /usr/local/go/src/runtime/asm_amd64.s:1581
#22 0x0000000000000000 in ?? ()

(gdb) info goroutines

    17 syscall runtime.notetsleepg
    2 waiting runtime.gopark
    3 waiting runtime.gopark
    4 waiting runtime.gopark
    19 runnable runtime.gcBgMarkWorker

(gdb) goroutine 17 bt
#0 runtime.notetsleepg (n=0x7fff23dc66e8 <runtime.work+232>, ns=-1) at /usr/local/go/src/runtime/lock_futex.go:237
#1 0x00007fff23c41338 in runtime.gcBgMarkStartWorkers () at /usr/local/go/src/runtime/mgc.go:1126
#2 0x00007fff23c3fd92 in runtime.gcStart (trigger=...) at /usr/local/go/src/runtime/mgc.go:637
#3 0x00007fff23c36e3d in runtime.mallocgc (size=565248, typ=0x7fff23cfd160, needzero=true) at /usr/local/go/src/runtime/malloc.go:1174
#4 0x00007fff23c6dfaa in runtime.growslice (et=, old=..., cap=) at /usr/local/go/src/runtime/slice.go:267
#5 0x00007fff23c918ef in regexp/syntax.(*compiler).inst (c=0xc000044bf8, op=) at /usr/local/go/src/regexp/syntax/compile.go:164
#6 regexp/syntax.(*compiler).rune (c=0xc000044bf8, r=[]int32 = {...}, flags=212) at /usr/local/go/src/regexp/syntax/compile.go:273
#7 0x00007fff23c90f1e in regexp/syntax.(*compiler).compile (c=0xc000044bf8, re=0xc00022a000) at /usr/local/go/src/regexp/syntax/compile.go:101
#8 0x00007fff23c8f805 in regexp/syntax.Compile (re=0xc00022a000) at /usr/local/go/src/regexp/syntax/compile.go:74
#9 0x00007fff23ca4a9a in regexp.compile (expr=,
mode=, longest=false) at /usr/local/go/src/regexp/regexp.go:178
#10 0x00007fff23ca5591 in regexp.Compile (expr=""") at /usr/local/go/src/regexp/regexp.go:133
#11 regexp.MustCompile (str=""") at /usr/local/go/src/regexp/regexp.go:309
#12 0x00007fff23ca8e0a in main.CheckPostAddress (buf=, bufLen=) at /root/codes/di_rechk/rechk.go:540
#13 0x00007fff23ca9a88 in _cgoexp_67df0785bef2_CheckPostAddress (a=0x7fffffffc740) at _cgo_gotypes.go:162
#14 0x00007fff23c2e21a in runtime.cgocallbackg1 (fn=0x7fff23ca9a60 <_cgoexp_67df0785bef2_CheckPostAddress>, frame=0x7fffffffc740, ctxt=0)
at /usr/local/go/src/runtime/cgocall.go:306
#15 0x00007fff23c2dee9 in runtime.cgocallbackg (fn=0x7fff23ca9a60 <_cgoexp_67df0785bef2_CheckPostAddress>, frame=0x7fffffffc740, ctxt=0)
at /usr/local/go/src/runtime/cgocall.go:232
#16 0x00007fff23c83791 in runtime.cgocallbackg (fn=0x7fff23ca9a60 <_cgoexp_67df0785bef2_CheckPostAddress>, frame=0x7fffffffc740, ctxt=0)
at :1
#17 0x00007fff23c813f3 in runtime.cgocallback () at /usr/local/go/src/runtime/asm_amd64.s:915
#18 0x00007fff23c81601 in runtime.goexit () at /usr/local/go/src/runtime/asm_amd64.s:1581
#19 0x0000000000000000 in ?? ()

(gdb) goroutine 2 bt
#0 runtime.gopark (unlockf=, lock=, reason=, traceEv=, traceskip=)
at /usr/local/go/src/runtime/proc.go:367
#1 0x00007fff23c5b86d in runtime.goparkunlock (reason=, traceEv=, traceskip=, lock=)
at /usr/local/go/src/runtime/proc.go:372
#2 runtime.forcegchelper () at /usr/local/go/src/runtime/proc.go:306
#3 0x00007fff23c81601 in runtime.goexit () at /usr/local/go/src/runtime/asm_amd64.s:1581
#4 0x0000000000000000 in ?? ()
(gdb) goroutine 3 bt
#0 runtime.gopark (unlockf=, lock=, reason=, traceEv=, traceskip=)
at /usr/local/go/src/runtime/proc.go:367
#1 0x00007fff23c48ee8 in runtime.goparkunlock (reason=, traceEv=, traceskip=, lock=)
at /usr/local/go/src/runtime/proc.go:372
#2 runtime.bgsweep () at /usr/local/go/src/runtime/mgcsweep.go:163
#3 0x00007fff23c81601 in runtime.goexit () at /usr/local/go/src/runtime/asm_amd64.s:1581
#4 0x0000000000000000 in ?? ()
(gdb) goroutine 4 bt
#0 runtime.gopark (unlockf=, lock=, reason=, traceEv=, traceskip=)
at /usr/local/go/src/runtime/proc.go:367
#1 0x00007fff23c46fed in runtime.goparkunlock (reason=, traceEv=, traceskip=, lock=)
at /usr/local/go/src/runtime/proc.go:372
#2 runtime.bgscavenge () at /usr/local/go/src/runtime/mgcscavenge.go:265
#3 0x00007fff23c81601 in runtime.goexit () at /usr/local/go/src/runtime/asm_amd64.s:1581
#4 0x0000000000000000 in ?? ()
(gdb) goroutine 19 bt
#0 runtime.gcBgMarkWorker () at /usr/local/go/src/runtime/mgc.go:1166
#1 0x00007fff23c81601 in runtime.goexit () at /usr/local/go/src/runtime/asm_amd64.s:1581
#2 0x0000000000000000 in ?? ()

(gdb) info threads
Id Target Id Frame
1 Thread 0x7ffff7966b80 (LWP 2024707) "nginx" runtime.futex () at /usr/local/go/src/runtime/sys_linux_amd64.s:520

    2 Thread 0x7ffef1ffb700 (LWP 2024717) "nginx" 0x00007ffff7a483bf in __GI___clock_nanosleep (clock_id=clock_id@entry=0, flags=flags@entry=0,
    req=req@entry=0x7ffef1ffae80, rem=rem@entry=0x0) at ../sysdeps/unix/sysv/linux/clock_nanosleep.c:78
    3 Thread 0x7ffef27fc700 (LWP 2024718) "ZMQbg/Reaper" 0x00007ffff7a8a5ce in epoll_wait (epfd=42, events=events@entry=0x7ffef27fb200,
    maxevents=maxevents@entry=256, timeout=timeout@entry=-1) at ../sysdeps/unix/sysv/linux/epoll_wait.c:30
    4 Thread 0x7ffef2ffd700 (LWP 2024719) "ZMQbg/IO/0" 0x00007ffff7a8a5ce in epoll_wait (epfd=44, events=events@entry=0x7ffef2ffc200,
    maxevents=maxevents@entry=256, timeout=timeout@entry=-1) at ../sysdeps/unix/sysv/linux/epoll_wait.c:30

我在这里做错了什么？

正确答案

我已经解决了这个问题，我从How to debug C-shared library (written in Go) - it hangs on net call得到了答案，你想知道原因，请访问网站。

我的程序运行在master-worker模型上，问题出现在work进程中。 我在fork子进程之前使用dlopen函数打开so文件，因此子进程没有go运行时线程。

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