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社区首页 >问答首页 >x64和x32中展开堆栈的不同行为

问x64和x32中展开堆栈的不同行为
EN

Stack Overflow用户
提问于 2012-02-29 23:50:07
回答 2查看 623关注 0票数 15

为什么在下面详细描述的场景中，堆栈空间在相同代码的x64中增加，而在x32中减少？

背景：

我们的客户可以用领域语言编写脚本，这些脚本在运行时使用递归技术解释，并在web服务器上执行。他们可能会在抛出异常的脚本中犯错误，这个异常会被捕获并记录下来。

由于这种递归技术，我们通过检查解释器执行脚本时使用的堆栈空间，并在实际运行堆栈之前终止脚本，来防止堆栈溢出异常。

在32位模式下，一切都运行良好，当脚本程序出错时，会生成一个Exception，它会被记录下来，堆栈展开，在此期间，堆栈上的剩余空间会增加，脚本也会很好地终止。

在64位模式下，一切都不是很好，当脚本程序出错时，会生成一个Exception，它会被记录下来，堆栈展开，在此期间，堆栈上剩余的空间会减少。这是非常糟糕的，因为如果脚本碰巧使用了大量堆栈空间并抛出错误，那么解开堆栈并记录错误本身的行为可能会导致StackOverflowException隐藏原始异常，软管IIS，并杀死所有正在运行的请求(坏的，非常坏的，非常非常糟糕的)。

重新创建问题：

这是一个控制台应用程序，它模拟我在生产中使用的代码，并在设置为x64时重新创建问题，并且在x32中运行良好。

using System;
using System.ComponentModel;
using System.Runtime.InteropServices;

namespace ConsoleApplication16
{
    class Program
    {
        const Int32 MaxNumberRecursions = 10;
        static Int32 _currentRecursionDepth;
        static UInt64 _lastSpaceUsed;

        static void Main(string[] args)
        {
            System.Diagnostics.Debug.WriteLine(String.Format("Is64BitProcess = {0}", System.Environment.Is64BitProcess));
            try
            {
                _lastSpaceUsed = GetStackBytesLeft();
                RecurseXTimes();
            }
            catch (Exception e)
            {
                System.Diagnostics.Debug.WriteLine(e);
            }
        }

        unsafe static void RecurseXTimes()
        {
            System.Diagnostics.Debug.WriteLine("--> RecurseXTimes()");
            ReportStackSpaceUsage();

            try
            {
                _currentRecursionDepth++;
                if (_currentRecursionDepth > MaxNumberRecursions)
                {
                    throw new Exception("Please unwind my stack");
                }

                System.Diagnostics.Debug.WriteLine(String.Format("Adding {0} bytes to stack.", sizeof(SomeDataToUseUpSomeStackSpace)));                
                SomeDataToUseUpSomeStackSpace someDataToUseUpSomeStackSpace = new SomeDataToUseUpSomeStackSpace();

                RecurseXTimes();
            }
            catch(Exception e)
            {
                //Do some logging. NOTE taking this "catch" out "fixes" the problem, but I can't do this in prod.
                System.Diagnostics.Debug.WriteLine(e.Message);
                throw;
            }
            finally
            {
                ReportStackSpaceUsage();
                System.Diagnostics.Debug.WriteLine("<-- RecurseXTimes()");
            }
        }

        private static void ReportStackSpaceUsage()
        {
            UInt64 stackUsed = GetStackBytesLeft();
            Int64 stackSpaceDelta = (Int64) stackUsed - (Int64) _lastSpaceUsed;
            Int64 stackSpaceDeltaAbs = Math.Abs(stackSpaceDelta);

            System.Diagnostics.Debug.WriteLine(
                String.Format("Stack space left: {0}. Stack Space Delta: {1} {2}", 
                                stackUsed,
                                stackSpaceDeltaAbs,
                                stackSpaceDelta < 0 ? "Allocated On Stack" : "Freed from Stack"));

            _lastSpaceUsed = stackUsed;
        }


        static unsafe ulong GetStackBytesLeft()
        {
            MEMORY_BASIC_INFORMATION stackInfo = new MEMORY_BASIC_INFORMATION();
            UIntPtr currentAddr = new UIntPtr(&stackInfo);
            int sizeT = VirtualQuery(currentAddr, ref stackInfo, sizeof(MEMORY_BASIC_INFORMATION));

            if (sizeT == 0)
            {
                //No Data Returned
                int lastError = Marshal.GetLastWin32Error();
                throw new Win32Exception(lastError);
            }

            UInt64 stackBytesLeft = currentAddr.ToUInt64() - stackInfo.AllocationBase.ToUInt64();
            return stackBytesLeft;
        }

        [DllImport("kernel32.dll", SetLastError = true)]
        static extern int VirtualQuery(UIntPtr lpAddress, ref MEMORY_BASIC_INFORMATION lpBuffer, int dwLength);

        [StructLayout(LayoutKind.Sequential)]
        struct MEMORY_BASIC_INFORMATION
        {
            public UIntPtr BaseAddress;
            public UIntPtr AllocationBase;
            public uint AllocationProtect;
            public UIntPtr RegionSize;
            public uint State;
            public uint Protect;
            public uint Type;
        };

        private struct SomeDataToUseUpSomeStackSpace
        {
            public Int64 a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20, a21, a22, a23, a24, a25;
            public Int64 b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16, b17, b18, b19, b20, b21, b22, b23, b24, b25;
            public Int64 c0, c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12, c13, c14, c15, c16, c17, c18, c19, c20, c21, c22, c23, c24, c25;
            public Int64 d0, d1, d2, d3, d4, d5, d6, d7, d8, d9, d10, d11, d12, d13, d14, d15, d16, d17, d18, d19, d20, d21, d22, d23, d24, d25;
            public Int64 e0, e1, e2, e3, e4, e5, e6, e7, e8, e9, e10, e11, e12, e13, e14, e15, e16, e17, e18, e19, e20, e21, e22, e23, e24, e25;
            public Int64 f0, f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12, f13, f14, f15, f16, f17, f18, f19, f20, f21, f22, f23, f24, f25;
            public Int64 g0, g1, g2, g3, g4, g5, g6, g7, g8, g9, g10, g11, g12, g13, g14, g15, g16, g17, g18, g19, g20, g21, g22, g23, g24, g25;
            public Int64 h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11, h12, h13, h14, h15, h16, h17, h18, h19, h20, h21, h22, h23, h24, h25;
            public Int64 i0, i1, i2, i3, i4, i5, i6, i7, i8, i9, i10, i11, i12, i13, i14, i15, i16, i17, i18, i19, i20, i21, i22, i23, i24, i25;
            public Int64 j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14, j15, j16, j17, j18, j19, j20, j21, j22, j23, j24, j25;
            public Int64 k0, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12, k13, k14, k15, k16, k17, k18, k19, k20, k21, k22, k23, k24, k25;
            public Int64 l0, l1, l2, l3, l4, l5, l6, l7, l8, l9, l10, l11, l12, l13, l14, l15, l16, l17, l18, l19, l20, l21, l22, l23, l24, l25;
            public Int64 m0, m1, m2, m3, m4, m5, m6, m7, m8, m9, m10, m11, m12, m13, m14, m15, m16, m17, m18, m19, m20, m21, m22, m23, m24, m25;
            public Int64 n0, n1, n2, n3, n4, n5, n6, n7, n8, n9, n10, n11, n12, n13, n14, n15, n16, n17, n18, n19, n20, n21, n22, n23, n24, n25;
            public Int64 o0, o1, o2, o3, o4, o5, o6, o7, o8, o9, o10, o11, o12, o13, o14, o15, o16, o17, o18, o19, o20, o21, o22, o23, o24, o25;
            public Int64 p0, p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15, p16, p17, p18, p19, p20, p21, p22, p23, p24, p25;
            public Int64 q0, q1, q2, q3, q4, q5, q6, q7, q8, q9, q10, q11, q12, q13, q14, q15, q16, q17, q18, q19, q20, q21, q22, q23, q24, q25;
            public Int64 r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, r16, r17, r18, r19, r20, r21, r22, r23, r24, r25;
            public Int64 s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14, s15, s16, s17, s18, s19, s20, s21, s22, s23, s24, s25;
            public Int64 t0, t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17, t18, t19, t20, t21, t22, t23, t24, t25;
            public Int64 u0, u1, u2, u3, u4, u5, u6, u7, u8, u9, u10, u11, u12, u13, u14, u15, u16, u17, u18, u19, u20, u21, u22, u23, u24, u25;
            public Int64 v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16, v17, v18, v19, v20, v21, v22, v23, v24, v25;
            public Int64 w0, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10, w11, w12, w13, w14, w15, w16, w17, w18, w19, w20, w21, w22, w23, w24, w25;
            public Int64 x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15, x16, x17, x18, x19, x20, x21, x22, x23, x24, x25;
            public Int64 y0, y1, y2, y3, y4, y5, y6, y7, y8, y9, y10, y11, y12, y13, y14, y15, y16, y17, y18, y19, y20, y21, y22, y23, y24, y25;
            public Int64 z0, z1, z2, z3, z4, z5, z6, z7, z8, z9, z10, z11, z12, z13, z14, z15, z16, z17, z18, z19, z20, z21, z22, z23, z24, z25;
        }
    }
}

示例输出：

x32 -一切都是花哨的，堆栈空间在下降时减少，在展开时增加。

Is64BitProcess = False
--> RecurseXTimes()
Stack space left: 1036512. Stack Space Delta: 5652 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1031004. Stack Space Delta: 5508 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1025496. Stack Space Delta: 5508 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1019988. Stack Space Delta: 5508 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1014480. Stack Space Delta: 5508 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1008972. Stack Space Delta: 5508 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1003464. Stack Space Delta: 5508 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 997956. Stack Space Delta: 5508 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 992448. Stack Space Delta: 5508 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 986940. Stack Space Delta: 5508 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 981432. Stack Space Delta: 5508 Allocated On Stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Please unwind my stack
Stack space left: 976816. Stack Space Delta: 4616 Allocated On Stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
<-- RecurseXTimes()
Please unwind my stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Stack space left: 982328. Stack Space Delta: 5512 Freed from Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 987832. Stack Space Delta: 5504 Freed from Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 993344. Stack Space Delta: 5512 Freed from Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 998848. Stack Space Delta: 5504 Freed from Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 1004360. Stack Space Delta: 5512 Freed from Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 1009864. Stack Space Delta: 5504 Freed from Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 1015376. Stack Space Delta: 5512 Freed from Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 1020880. Stack Space Delta: 5504 Freed from Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 1026392. Stack Space Delta: 5512 Freed from Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 1031896. Stack Space Delta: 5504 Freed from Stack
<-- RecurseXTimes()
System.Exception: Please unwind my stack

这是在x64中使用完全相同的代码的输出，堆栈空间在下降时增加，但在展开过程中持续减少：

Is64BitProcess = True
--> RecurseXTimes()
Stack space left: 1034256. Stack Space Delta: 5696 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1028704. Stack Space Delta: 5552 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1023152. Stack Space Delta: 5552 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1017600. Stack Space Delta: 5552 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1012048. Stack Space Delta: 5552 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1006496. Stack Space Delta: 5552 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 1000944. Stack Space Delta: 5552 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 995392. Stack Space Delta: 5552 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 989840. Stack Space Delta: 5552 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 984288. Stack Space Delta: 5552 Allocated On Stack
Adding 5408 bytes to stack.
--> RecurseXTimes()
Stack space left: 978736. Stack Space Delta: 5552 Allocated On Stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Please unwind my stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Stack space left: 957392. Stack Space Delta: 21344 Allocated On Stack
<-- RecurseXTimes()
Please unwind my stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Stack space left: 948880. Stack Space Delta: 8512 Allocated On Stack
<-- RecurseXTimes()
Please unwind my stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Stack space left: 940368. Stack Space Delta: 8512 Allocated On Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 931856. Stack Space Delta: 8512 Allocated On Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 923344. Stack Space Delta: 8512 Allocated On Stack
<-- RecurseXTimes()
Please unwind my stack
Stack space left: 914832. Stack Space Delta: 8512 Allocated On Stack
<-- RecurseXTimes()
Please unwind my stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Stack space left: 906320. Stack Space Delta: 8512 Allocated On Stack
<-- RecurseXTimes()
Please unwind my stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Stack space left: 897808. Stack Space Delta: 8512 Allocated On Stack
<-- RecurseXTimes()
Please unwind my stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Stack space left: 889296. Stack Space Delta: 8512 Allocated On Stack
<-- RecurseXTimes()
Please unwind my stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Stack space left: 880784. Stack Space Delta: 8512 Allocated On Stack
<-- RecurseXTimes()
Please unwind my stack
A first chance exception of type 'System.Exception' occurred in ConsoleApplication16.exe
Stack space left: 872272. Stack Space Delta: 8512 Allocated On Stack
<-- RecurseXTimes()
System.Exception: Please unwind my stack

奇怪的是，如果我删除了" catch“，那么在64位下它会保持堆栈的使用率不变--但我不能在prodcuction中这样做，因为我需要在catch中做日志记录。

c#
.net
exception
stack-overflow
stack-unwinding
EN

回答 2

Stack Overflow用户

发布于 2012-03-05 19:45:07

当您重新抛出异常时，似乎正在分配额外的内存块。因此您仍然可以在您的生产代码中捕获它。

广泛的研究(实际上是谷歌)表明，在x64模式下，x64 stack unwind metadata可能是额外分配的关键。

我在您的示例代码中更改了RecurseXTimes中的异常捕获，以便：

通过BinaryFormatter，

  • 将异常记录为currently
  • Serializes it

在下面的代码末尾，最后反序列化并抛出它。在32位和64位模式下，堆栈展开轨迹现在看起来非常相似。

好的，你失去了异常站点的可见性，但无论如何它是递归的，所以至少函数名是正确的。而且您可能必须弄清楚如何分配足够的内存来序列化它！

编辑这里是我所做的调整：

        catch (Exception e)
        {
            //Do some logging. NOTE taking this "catch" out "fixes" the problem, but I can't do this in prod.
            System.Diagnostics.Debug.WriteLine(e.Message);
            caughtException = new MemoryStream();
            BinaryFormatter exceptionFormatter = new BinaryFormatter(); // Exception raised on this line
            exceptionFormatter.Serialize(caughtException, e);
            caughtException.Seek(0, SeekOrigin.Begin);
        }
        finally
        {
            ReportStackSpaceUsage();
            System.Diagnostics.Debug.WriteLine("<-- RecurseXTimes()");
            if (caughtException != null)
            {
                BinaryFormatter exceptionFormatter = new BinaryFormatter();
                Exception e = (Exception)exceptionFormatter.Deserialize(caughtException);
                throw e;
            }
        }

希望在你真正的应用程序中有足够的余量来做到这一点，而不需要第二个OutOfMemoryException。

票数 1
EN

Stack Overflow用户

发布于 2012-03-01 12:48:41

像这样使用大量内存的递归，可以通过使用Stack对象在堆中执行。您可以自己增加/减少它，从而获得更大的内存空间。

票数 -2
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：

https://stackoverflow.com/questions/9502243

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