为什么在下面详述的场景中，堆栈空间在 x64 中增加而在 x32 中减少，代码相同？
背景:
我们的客户可以使用领域语言编写脚本，该语言在运行时使用递归技术进行解释并在网络服务器上执行。他们可能会在脚本中犯错误而引发异常，该异常会被捕获并记录。
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来防止堆栈溢出异常，并在我们实际用完堆栈之前终止脚本。
在 32 位模式下一切正常，当脚本编写器出错时 Exception生成，记录，堆栈展开，在此期间堆栈上剩余的空间增加并且脚本很好地终止。
在 64 位模式下，一切都不太好，当脚本编写器出错时 Exception生成，记录，堆栈展开，在此期间堆栈上剩余的空间减少。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异常，那么展开堆栈并记录错误本身的行为可能会导致 StackOverflowException。它隐藏了最初的异常，处理 IIS，并杀死所有飞行中的请求(坏的，非常坏的，非常非常坏的)。
重现问题:
这是一个控制台应用程序，它对我在生产中使用的代码进行建模并在设置为 x64 时重现问题，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 - 一切都很好，堆栈空间递减减少，并在展开期间增加。
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 中具有完全相同代码的输出，堆栈空间在递减的同时增加，但在展开期间不断减少:
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“Catch”，那么在 64 位下它会保持使用相同的堆栈 - 但我不能在生产中这样做，因为我需要在 catch 中进行日志记录。
最佳答案
当你重新抛出异常时，似乎正在分配额外的内存块。所以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 x64 stack unwind metadata可能是 x64 模式下额外分配的 cuplrit。
我在您的示例代码中更改了 RecurseXTimes 中的异常捕获，以便它:
并在下面最后 Deserialze 并抛出它。堆栈展开跟踪现在在 32 位和 64 位模式之间看起来非常相似。
好吧，你失去了异常站点的可见性，但无论如何它是递归的，所以至少函数名称是正确的..你可能必须弄清楚如何分配足够的内存来序列化它!
[编辑] 这是我所做的调整:
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;
}
}
希望在您的真实应用中有足够的余量来执行此操作而不会出现辅助 OutOfMemoryException。
关于c# - x64 和 x32 中的不同行为展开堆栈，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/9502243/
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我需要从一个View访问多个模型。以前，我的links_controller仅用于提供以不同方式排序的链接资源。现在我想包括一个部分(我假设)显示按分数排序的顶级用户(@users=User.all.sort_by(&:score))我知道我可以将此代码插入每个链接操作并从View访问它，但这似乎不是“ruby方式”，我将需要在不久的将来访问更多模型。这可能会变得很脏，是否有针对这种情况的任何技术？注意事项:我认为我的应用程序正朝着单一格式和动态页面内容的方向发展，本质上是一个典型的网络应用程序。我知道before_filter但考虑到我希望应用程序进入的方向，这似乎很麻烦。最终从任何
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刚入门rails，开始慢慢理解。有人可以解释或给我一些关于在application_controller中编码的好处或时间和原因的想法吗？有哪些用例。您如何为Rails应用程序使用应用程序Controller？我不想在那里放太多代码，因为据我了解，每个请求都会调用此Controller。这是真的？ 最佳答案 ApplicationController实际上是您应用程序中的每个其他Controller都将从中继承的类(尽管这不是强制性的)。我同意不要用太多代码弄乱它并保持干净整洁的态度，尽管在某些情况下ApplicationContr
我想向我的Controller传递一个参数，它是一个简单的复选框，但我不知道如何在模型的form_for中引入它，这是我的观点:{:id=>'go_finance'}do|f|%>Transferirde:para:Entrada:"input",:placeholder=>"Quantofoiganho?"%>Saída:"output",:placeholder=>"Quantofoigasto?"%>Nota:我想做一个额外的复选框，但我该怎么做，模型中没有一个对象，而是一个要检查的对象，以便在Controller中创建一个ifelse，如果没有检查，请帮助我，非常感谢,谢谢