goland等待锁 浅析goland等待锁问题
Skyego 人气:0问题描述:
向后台发送了一个URL请求,竟然一直卡住,没有返回,就一直卡着
问题分析定位:
一开始还以为是网络,还是什么其它奇怪的原因,毕竟之前好好的。
这里应该第一时间思考环境的变化,网络、程序版本、还是什么地方变化了。
后来又试了好几次,发现还是一样,想到了将Pod的数目改成了2个,于是估计是等待锁或者死锁之类的。
通过以下链接获取调试信息:
curl “127.0.0.1:43411/debug/pprof/goroutine?debug=1” > 1.out
curl “127.0.0.1:43411/debug/pprof/goroutine?debug=2” > 1.log
搜索卡住的请求方法名,果真搜到一些,goroutine 17002 [semacquire, 5 minutes]:表示17002这个goroutine正在等待获取锁,等了5分钟了。
又有一个正在运行中的同名方法,估计是大家都在等它的锁,看来代码,果然有一个锁。
但是这个goroutine调用栈最上层是SetDataNodeCarry,看到其方法内部,发现其也加了一个锁,不过其就是简单的对一个字段的变更进行加锁。
分析其使用的锁相关的代码,大家没有重叠,每一次加锁只不过是保证数据的原子性和一致性而已,所以不会有死锁的问题。
阅读SetDataNodeCarry附近的代码,有一个for availCarryCount < needSelectedNum {},之前没仔细看,这里竟然可能是一个死循环,分析了一下环境的变化,果然是因为环境不同了,导致这里的循环无法跳出。
总结
遇到此类问题首先不能慌,之后不能逃避问题。
需要将问题尽可能地记录,以便于还原,同时还要基于现在的情况进行调试,千万不能想着重启会好,不能逃避问题。
后面解决问题的步骤还可以,不过这个问题本身也不是很难。
------------记录
1 @ 0x47fc42 0x80fb0d 0x811270 0x80b86e 0x7ba758 0x7e0686 0x7f24fa 0x81d712 0x6ff9b4 0x7018b6 0x702c88 0x6fe971 0x469581 #0x47fc41 sync.(*RWMutex).Unlock+0xb1 /usr/local/go/src/sync/rwmutex.go:113 #0x80fb0c [go文件路径]m.(*Pod).SetDataNodeCarry+0x6c /go/src/[go文件路径]m/t.go:777 #0x81126f [go文件路径]m.pts.ptsn+0x5f /go/src/[go文件路径]m/t.go:1059 #0x80b86d [go文件路径]m.(*t).ctcpd+0x83d /go/src/[go文件路径]m/t.go:453 #0x7ba757 [go文件路径]m.(*c).cDP+0x1e7 /go/src/[go文件路径]m/c.go:558 #0x7e0685 [go文件路径]m.(*m).cDP+0x375 /go/src/[go文件路径]m/handle_admin.go:353 #0x7f24f9 [go文件路径]m.(*m).ServeHTTP+0x1659 /go/src/[go文件路径]m/http_server.go:188 #0x81d711 [go文件路径]m.(*m).handlerWithInterceptor.func1+0x81 /go/src/[go文件路径]m/http_server.go:160 #0x6ff9b3 net/http.HandlerFunc.ServeHTTP+0x43 /usr/local/go/src/net/http/server.go:1995 #0x7018b5 net/http.(*ServeMux).ServeHTTP+0x1d5 /usr/local/go/src/net/http/server.go:2375 #0x702c87 net/http.serverHandler.ServeHTTP+0xa7 /usr/local/go/src/net/http/server.go:2774 #0x6fe970 net/http.(*conn).serve+0x850 /usr/local/go/src/net/http/server.go:1878 2 @ 0x43c20f 0x44c609 0x44c5df 0x44c37d 0x47ecb9 0x7ba6ad 0x7e0686 0x7f24fa 0x81d712 0x6ff9b4 0x7018b6 0x702c88 0x6fe971 0x469581 #0x44c37c sync.runtime_SemacquireMutex+0x3c /usr/local/go/src/runtime/sema.go:71 #0x47ecb8 sync.(*Mutex).Lock+0x108 /usr/local/go/src/sync/mutex.go:134 #0x7ba6ac [go文件路径]m.(*c).cDP+0x13c /go/src/[go文件路径]m/c.go:554 #0x7e0685 [go文件路径]m.(*m).cDP+0x375 /go/src/[go文件路径]m/handle_admin.go:353 #0x7f24f9 [go文件路径]m.(*m).ServeHTTP+0x1659 /go/src/[go文件路径]m/http_server.go:188 #0x81d711 [go文件路径]m.(*m).handlerWithInterceptor.func1+0x81 /go/src/[go文件路径]m/http_server.go:160 #0x6ff9b3 net/http.HandlerFunc.ServeHTTP+0x43 /usr/local/go/src/net/http/server.go:1995 #0x7018b5 net/http.(*ServeMux).ServeHTTP+0x1d5 /usr/local/go/src/net/http/server.go:2375 #0x702c87 net/http.serverHandler.ServeHTTP+0xa7 /usr/local/go/src/net/http/server.go:2774 #0x6fe970 net/http.(*conn).serve+0x850 /usr/local/go/src/net/http/server.go:1878
goroutine 13994 [runnable]: sync.(*Mutex).Lock(0xc002300468) /usr/local/go/src/sync/mutex.go:72 +0x2c9 sync.(*RWMutex).Lock(0xc002300468) /usr/local/go/src/sync/rwmutex.go:93 +0x2d [go文件路径]m.(*Pod).SetDataNodeCarry(0xc0023003f0, 0x4024000000000000) /go/src/[go文件路径]m/t.go:774 +0x36 [go文件路径]m.pts.ptsn(0xc003b17810, 0x2, 0x2, 0x0, 0x3) /go/src/[go文件路径]m/t.go:1059 +0x60 [go文件路径]m.(*t).ctcpd(0xc0000ef090, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x3, 0x6, 0xc002275958, ...) /go/src/[go文件路径]m/t.go:453 +0x83e [go文件路径]m.(*c).cDP(0xc00223c000, 0xc00286e673, 0xe, 0xc00286e65f, 0x6, 0x0, 0x0, 0x0) /go/src/[go文件路径]m/c.go:558 +0x1e8 [go文件路径]m.(*m).cDP(0xc0009aca90, 0xabfd80, 0xc0031a1260, 0xc00296be00) /go/src/[go文件路径]m/handle_admin.go:353 +0x376 [go文件路径]m.(*m).ServeHTTP(0xc0009aca90, 0xabfd80, 0xc0031a1260, 0xc00296be00) /go/src/[go文件路径]m/http_server.go:188 +0x165a [go文件路径]m.(*m).handlerWithInterceptor.func1(0xabfd80, 0xc0031a1260, 0xc00296be00) /go/src/[go文件路径]m/http_server.go:160 +0x82 net/http.HandlerFunc.ServeHTTP(0xc000990300, 0xabfd80, 0xc0031a1260, 0xc00296be00) /usr/local/go/src/net/http/server.go:1995 +0x44 net/http.(*ServeMux).ServeHTTP(0x10a3520, 0xabfd80, 0xc0031a1260, 0xc00296be00) /usr/local/go/src/net/http/server.go:2375 +0x1d6 net/http.serverHandler.ServeHTTP(0xc0000dad00, 0xabfd80, 0xc0031a1260, 0xc00296be00) /usr/local/go/src/net/http/server.go:2774 +0xa8 net/http.(*conn).serve(0xc003b19860, 0xac1d80, 0xc0009a9e40) /usr/local/go/src/net/http/server.go:1878 +0x851 created by net/http.(*Server).Serve /usr/local/go/src/net/http/server.go:2884 +0x2f4 goroutine 17002 [semacquire, 5 minutes]: sync.runtime_SemacquireMutex(0xc0026fc460, 0x419400) /usr/local/go/src/runtime/sema.go:71 +0x3d sync.(*Mutex).Lock(0xc0026fc45c) /usr/local/go/src/sync/mutex.go:134 +0x109 [go文件路径]m.(*c).cDP(0xc00223c000, 0xc00002a083, 0xe, 0xc00002a06f, 0x6, 0x0, 0x0, 0x0) /go/src/[go文件路径]m/c.go:554 +0x13d [go文件路径]m.(*m).cDP(0xc0009aca90, 0xabfd80, 0xc0031a0620, 0xc002988900) /go/src/[go文件路径]m/handle_admin.go:353 +0x376 [go文件路径]m.(*m).ServeHTTP(0xc0009aca90, 0xabfd80, 0xc0031a0620, 0xc002988900) /go/src/[go文件路径]m/http_server.go:188 +0x165a [go文件路径]m.(*m).handlerWithInterceptor.func1(0xabfd80, 0xc0031a0620, 0xc002988900) /go/src/[go文件路径]m/http_server.go:160 +0x82 net/http.HandlerFunc.ServeHTTP(0xc000990300, 0xabfd80, 0xc0031a0620, 0xc002988900) /usr/local/go/src/net/http/server.go:1995 +0x44 net/http.(*ServeMux).ServeHTTP(0x10a3520, 0xabfd80, 0xc0031a0620, 0xc002988900) /usr/local/go/src/net/http/server.go:2375 +0x1d6 net/http.serverHandler.ServeHTTP(0xc0000dad00, 0xabfd80, 0xc0031a0620, 0xc002988900) /usr/local/go/src/net/http/server.go:2774 +0xa8 net/http.(*conn).serve(0xc003b18640, 0xac1d80, 0xc00298e940) /usr/local/go/src/net/http/server.go:1878 +0x851 created by net/http.(*Server).Serve /usr/local/go/src/net/http/server.go:2884 +0x2f4 goroutine 14532 [semacquire, 11 minutes]: sync.runtime_SemacquireMutex(0xc0026fc460, 0x419400) /usr/local/go/src/runtime/sema.go:71 +0x3d sync.(*Mutex).Lock(0xc0026fc45c) /usr/local/go/src/sync/mutex.go:134 +0x109 [go文件路径]m.(*c).cDP(0xc00223c000, 0xc003f74303, 0xe, 0xc003f742ef, 0x6, 0x0, 0x0, 0x0) /go/src/[go文件路径]m/c.go:554 +0x13d [go文件路径]m.(*m).cDP(0xc0009aca90, 0xabfd80, 0xc00454a620, 0xc004544800) /go/src/[go文件路径]m/handle_admin.go:353 +0x376 [go文件路径]m.(*m).ServeHTTP(0xc0009aca90, 0xabfd80, 0xc00454a620, 0xc004544800) /go/src/[go文件路径]m/http_server.go:188 +0x165a [go文件路径]m.(*m).handlerWithInterceptor.func1(0xabfd80, 0xc00454a620, 0xc004544800) /go/src/[go文件路径]m/http_server.go:160 +0x82 net/http.HandlerFunc.ServeHTTP(0xc000990300, 0xabfd80, 0xc00454a620, 0xc004544800) /usr/local/go/src/net/http/server.go:1995 +0x44 net/http.(*ServeMux).ServeHTTP(0x10a3520, 0xabfd80, 0xc00454a620, 0xc004544800) /usr/local/go/src/net/http/server.go:2375 +0x1d6 net/http.serverHandler.ServeHTTP(0xc0000dad00, 0xabfd80, 0xc00454a620, 0xc004544800) /usr/local/go/src/net/http/server.go:2774 +0xa8 net/http.(*conn).serve(0xc002e17540, 0xac1d80, 0xc002a74780) /usr/local/go/src/net/http/server.go:1878 +0x851 created by net/http.(*Server).Serve /usr/local/go/src/net/http/server.go:2884 +0x2f4
总结
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