.NET Windbg分析某婦產醫院WPF記憶體溢位

2022-06-02 22:00:37

一：背景

1. 講故事

上個月有位朋友找到我，說他的程式存在記憶體溢位情況，尋求如何解決。

要解決還得通過 windbg 分析啦。

二：Windbg 分析

1. 為什麼會記憶體溢位

大家都知道記憶體溢位對應著 .NET 中的 OutOfMemoryException 異常，這種異常有可能是受控程式碼手工丟擲的，也有可能是CLR層面丟擲的，言外之意就是可以通過兩種方式排查。

託管執行緒是否掛載著異常？

0:000> !t
ThreadCount:      23
UnstartedThread:  0
BackgroundThread: 5
PendingThread:    0
DeadThread:       17
Hosted Runtime:   no
                                                                         Lock  
       ID OSID ThreadOBJ    State GC Mode     GC Alloc Context  Domain   Count Apt Exception
   0    1 362c 00fac868     26020 Preemptive  7ED701A0:00000000 00fa6b60 0     STA 
   5    2 2d70 00fbeba0     2b220 Preemptive  7EBA7AC0:00000000 00fa6b60 0     MTA (Finalizer) 
   7    3 3264 061c8890   102a220 Preemptive  00000000:00000000 00fa6b60 0     MTA (Threadpool Worker) 
  17   15 3f98 19682b90   202b220 Preemptive  7EBB0830:00000000 00fa6b60 0     MTA 
XXXX   16    0 2845fb00     35820 Preemptive  00000000:00000000 00fa6b60 0     Ukn 
  18   14  a7c 2842b1c8   202b220 Preemptive  00000000:00000000 00fa6b60 0     MTA 
XXXX    6    0 2c9b3778   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   18    0 288a1318   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   23    0 288a22f0   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   10    0 2ccf3550   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   21    0 288a1860   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   12    0 288a1da8   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   11    0 2c993640   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX    8    0 2ccf3a98     35820 Preemptive  00000000:00000000 00fa6b60 0     Ukn 
XXXX    9    0 2ccf2030   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX    7    0 2c9aed88   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   26    0 28898308   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   25    0 2c492c68   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX    4    0 2c993b88   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   20    0 2c9af2d0   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   17    0 2c9afd60   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
XXXX   24    0 2c9b1280   1039820 Preemptive  00000000:00000000 00fa6b60 0     Ukn (Threadpool Worker) 
  23   22 2658 2c9b02a8   1029220 Preemptive  7ED5BFF8:00000000 00fa6b60 0     MTA (Threadpool Worker)

從輸出資訊看，這些執行緒並沒有掛載任何託管異常，我去。。。

是否在 CLR 上丟擲

這主要是看託管堆(heap) 上的記憶體分配或者gc回收造成的記憶體不足，可以用 !ao 命令。

0:000> !ao
There was no managed OOM due to allocations on the GC heap

從輸出資訊看也沒有任何異常，尷尬了

.NET Windbg分析某婦產醫院WPF記憶體溢位

目錄

一：背景

1. 講故事

二：Windbg 分析

1. 為什麼會記憶體溢位

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