编辑在你兴奋之前，看看最后的重要编辑，如果你仍然好奇，这些报告如下：
- http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=696222
- http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=696263
我一直在尝试一段代码，并惊讶地发现我没有得到 stackoverflow。试图简化事情，我什至做到了这一点：
#include <stdio.h>
int main()
{
int i;
/* 1,500,000,000 x 4 bytes = 6,000,000,000 bytes = 6GB */
int size = 1500000000;
int arr[size];
for (i = 0; i < size; i++) {
arr[i] = 1;
}
printf("first: %d\n", arr[0]);
printf("last: %d\n", arr[size - 1]);
return 0;
}
这让我怀疑我什至不知道内存管理的基础知识。我在想arr[size]应该在堆栈上分配并轻松溢出，但它使用了我所有的内存并交换并成功完成。我错过了什么？
笔记
- 我在 64 位 ubuntu 12.04 上运行
我尝试过使用
gcc和clang使用版本：gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3 Ubuntu clang version 3.0-6ubuntu3 (tags/RELEASE_30/final) (based on LLVM 3.0)我已关闭优化 (
-O0)运行
ulimit -a我得到：core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 29569 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 29569 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited我有
4GBram 和大约相同数量的交换
(gdb) disassemble main
Dump of assembler code for function main:
0x00000000004004f4 <+0>: push %rbp
0x00000000004004f5 <+1>: mov %rsp,%rbp
0x00000000004004f8 <+4>: push %rbx
0x00000000004004f9 <+5>: sub $0x38,%rsp
0x00000000004004fd <+9>: mov %rsp,%rax
0x0000000000400500 <+12>: mov %rax,%rbx
0x0000000000400503 <+15>: movl $0x59682f00,-0x14(%rbp)
0x000000000040050a <+22>: mov -0x14(%rbp),%eax
0x000000000040050d <+25>: movslq %eax,%rdx
0x0000000000400510 <+28>: sub $0x1,%rdx
0x0000000000400514 <+32>: mov %rdx,-0x28(%rbp)
0x0000000000400518 <+36>: cltq
0x000000000040051a <+38>: shl $0x2,%rax
0x000000000040051e <+42>: lea 0xf(%rax),%rdx
0x0000000000400522 <+46>: mov $0x10,%eax
0x0000000000400527 <+51>: sub $0x1,%rax
0x000000000040052b <+55>: add %rdx,%rax
0x000000000040052e <+58>: movq $0x10,-0x38(%rbp)
0x0000000000400536 <+66>: mov $0x0,%edx
0x000000000040053b <+71>: divq -0x38(%rbp)
0x000000000040053f <+75>: imul $0x10,%rax,%rax
0x0000000000400543 <+79>: sub %rax,%rsp
0x0000000000400546 <+82>: mov %rsp,%rax
0x0000000000400549 <+85>: add $0xf,%rax
0x000000000040054d <+89>: shr $0x4,%rax
0x0000000000400551 <+93>: shl $0x4,%rax
0x0000000000400555 <+97>: mov %rax,-0x20(%rbp)
0x0000000000400559 <+101>: movl $0x0,-0x18(%rbp)
0x0000000000400560 <+108>: jmp 0x400577 <main+131>
0x0000000000400562 <+110>: mov -0x20(%rbp),%rax
0x0000000000400566 <+114>: mov -0x18(%rbp),%edx
0x0000000000400569 <+117>: movslq %edx,%rdx
0x000000000040056c <+120>: movl $0x1,(%rax,%rdx,4)
0x0000000000400573 <+127>: addl $0x1,-0x18(%rbp)
0x0000000000400577 <+131>: mov -0x18(%rbp),%eax
0x000000000040057a <+134>: cmp -0x14(%rbp),%eax
0x000000000040057d <+137>: jl 0x400562 <main+110>
0x000000000040057f <+139>: mov -0x20(%rbp),%rax
0x0000000000400583 <+143>: mov (%rax),%edx
0x0000000000400585 <+145>: mov $0x4006bc,%eax
0x000000000040058a <+150>: mov %edx,%esi
0x000000000040058c <+152>: mov %rax,%rdi
0x000000000040058f <+155>: mov $0x0,%eax
---Type <return> to continue, or q <return> to quit---
0x0000000000400594 <+160>: callq 0x4003f0 <printf@plt>
0x0000000000400599 <+165>: mov -0x14(%rbp),%eax
0x000000000040059c <+168>: lea -0x1(%rax),%edx
0x000000000040059f <+171>: mov -0x20(%rbp),%rax
0x00000000004005a3 <+175>: movslq %edx,%rdx
0x00000000004005a6 <+178>: mov (%rax,%rdx,4),%edx
0x00000000004005a9 <+181>: mov $0x4006c7,%eax
0x00000000004005ae <+186>: mov %edx,%esi
0x00000000004005b0 <+188>: mov %rax,%rdi
0x00000000004005b3 <+191>: mov $0x0,%eax
0x00000000004005b8 <+196>: callq 0x4003f0 <printf@plt>
0x00000000004005bd <+201>: mov $0x0,%eax
0x00000000004005c2 <+206>: mov %rbx,%rsp
0x00000000004005c5 <+209>: mov -0x8(%rbp),%rbx
0x00000000004005c9 <+213>: leaveq
0x00000000004005ca <+214>: retq
End of assembler dump.
$ pmap 2840
2840: ./a.out
0000000000400000 4K r-x-- /home/gokce/play/a.out
0000000000600000 4K r---- /home/gokce/play/a.out
0000000000601000 4K rw--- /home/gokce/play/a.out
00002b572d7be000 136K r-x-- /lib/x86_64-linux-gnu/ld-2.15.so
00002b572d7e0000 8K rw--- [ anon ]
00002b572d9e0000 4K r---- /lib/x86_64-linux-gnu/ld-2.15.so
00002b572d9e1000 8K rw--- /lib/x86_64-linux-gnu/ld-2.15.so
00002b572d9e3000 1748K r-x-- /lib/x86_64-linux-gnu/libc-2.15.so
00002b572db98000 2044K ----- /lib/x86_64-linux-gnu/libc-2.15.so
00002b572dd97000 16K r---- /lib/x86_64-linux-gnu/libc-2.15.so
00002b572dd9b000 8K rw--- /lib/x86_64-linux-gnu/libc-2.15.so
00002b572dd9d000 28K rw--- [ anon ]
00007ffe080a2000 5859388K rw--- [ stack ]
00007fff6dbfc000 4K r-x-- [ anon ]
ffffffffff600000 4K r-x-- [ anon ]
total 5863408K
重要编辑
我正在使用一个小的手写makefile：
build:
gcc foo.c -Wall -Wextra -g
run:
./a.out
.SILENT:
使用我常用的编辑器镜头运行程序，我现在意识到它在某种程度上是相关的。当我使用以下命令从控制台运行时出现段错误：
./a.out
但不是当我运行时：
make run
这有什么关系？
重要编辑2
当我尝试像这样运行ulimit -s时make run：
build:
gcc foo.c -Wall -Wextra -g
run:
ulimit -s
.SILENT:
它给：
make: ulimit: Command not found
make: *** [run] Error 127
然后我意识到当我最后添加额外内容时它会发生变化#：（不是评论字符吗？）
build:
gcc foo.c -Wall -Wextra -g
run:
ulimit -s #
.SILENT:
我得到：
unlimited
我还检查了我的 bash 别名，但没有make. which make给予/usr/bin/make和file /usr/bin/make给予：
/usr/bin/make: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically
linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=0x1d76b881b71091d
37e6653d7c8b8e19a2a414591, stripped