我的程序中出现此错误...
mprotect: Cannot allocate memory
ulimit -a 给出输出:
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 20
file size (blocks, -f) unlimited
pending signals (-i) 16382
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) unlimited
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
我想要保护的内存量是60 MB。有人能告诉我问题是什么以及如何解决?
答案 0 :(得分:2)
Return Value
On success, mprotect() returns zero.
On error, -1 is returned, and errno is set appropriately.
Errors
EACCES
The memory cannot be given the specified access. This can happen, for example, if
you mmap(2) a file to which you have read-only access, then ask mprotect() to
mark it PROT_WRITE.
EFAULT
The memory cannot be accessed.
EINVAL
addr is not a valid pointer, or not a multiple of PAGESIZE.
ENOMEM
Internal kernel structures could not be allocated.
Or: addresses in the range [addr, addr+len] are invalid for the address space of
the process, or specify one or more pages that are not mapped.
鉴于错误消息,您可能遇到ENOMEM
错误,并查看错误代码,这并不一定意味着无法分配内存。您可能具有无效的地址范围,或者(很可能)您的页面未映射。
不要试图在一个膨胀的泡沫中保护这么大的记忆。鉴于虚拟内存如何工作,可能性太大,以至于不会映射该巨大块中的某些页面。在调用mprotect之前,您需要确保映射有问题的页面(页面)。
当您使用系统函数时,最好阅读该函数的手册页。然后重新阅读它。手册页有时可能有点简洁。
答案 1 :(得分:0)
虽然我认为这不是你的问题,但也应该注意mprotect
由于分配失败肯定会失败,至少有两个原因:
munmap
也可能由于同样的原因而失败!)