mmap giving Permission Denied error

[Ravi Teja]

Hello Ratheesh,

I have intentionally used MAP_FIXED flag as* *I am interested in mapping to
0x00000000.

Even after setting the mmap_min_addr in /proc/sys/vm to 0 (which was
previously 4096), I am getting this error.

Is there anything wrong that I am doing?


On Sat, Sep 21, 2013 at 7:17 PM, ratheesh kannoth <ratheesh.ksz at gmail.com>wrote:

> MAP_FIXED could be trying to get a map from  0.
>
>
> Pls remove this flag and try.
>
>
> On Sat, Sep 21, 2013 at 6:55 PM, Ravi Teja <ravi2j at gmail.com> wrote:
>
>> Hello all,
>>
>> I tried mmap'ing to address zero after setting *
>> /proc/sys/vm/mmap_min_addr* to* 0*, but mmap is giving Permission Denied
>> error.
>>
>> My C code is as below -
>>
>> #include <stdio.h>
>> #include <stdlib.h>
>> #include <sys/mman.h>
>>
>> int main(void)
>> {
>> int *ptr = NULL;
>>  ptr =
>> mmap(0,4096,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,-1,0);
>> if(ptr == MAP_FAILED)
>>  {
>> perror("Error in mapping\n");
>> exit(1);
>>  }
>> printf("After mmap\n");
>> *ptr = 16;
>> printf("Contents of address 0x%x is :: %d\n",ptr,*ptr);
>>  return 0;
>> }
>>
>> Am I doing anything wrong here?
>>
>> Thank you in advance.
>>
>> Regards,
>> Ravi Teja
>>
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>>
>
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