Bug in xc_gntshr_munmap

Bug in xc_gntshr_munmap

[Vincent Bernardoff]

[-- Attachment #1: Type: text/plain, Size: 194 bytes --]

Hi,

On the little program attached, xc_gntshr_munmap looks like it is not 
correctly un-sharing shared pages. Am I using these functions as they 
are intented to ?

Thanks in advance,

Vincent

[-- Attachment #2: libxc_gntshr_bug.c --]
[-- Type: text/x-csrc, Size: 727 bytes --]

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <xenctrl.h>

int main(int argc, char** argv)
{
  int ret, i;
  uint32_t refs[2] = {0};
  void* pages;

  xc_gntshr *h = xc_gntshr_open(NULL, 0);

  if (h == NULL)
    {
      perror("xc_gntshr_open");
      exit (1);
    }

  for(i=0; i<10000; i++)
    {
      pages = xc_gntshr_share_pages(h, 0, 2, refs, 1);
      if (pages == NULL)
        {
          fprintf(stderr, "xc_gntshr_share_pages failed at the %dth iteration.\n", i);
          perror("xc_gntshr_share_pages");
          exit (1);
        }
      if(xc_gntshr_munmap(h, pages, 2) != 0)
        {
          perror("xc_gntshr_munmap");
          exit (1);
        }
    }

  xc_gntshr_close(h);
}

[-- Attachment #3: Type: text/plain, Size: 126 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

Re: Bug in xc_gntshr_munmap

[Ian Campbell]

On Fri, 2013-07-19 at 11:18 +0100, Vincent Bernardoff wrote:
> Hi,
> 
> On the little program attached, xc_gntshr_munmap looks like it is not 
> correctly un-sharing shared pages. Am I using these functions as they 
> are intented to ?
> 

Marek Marczykowski posted some patches back in April/May about a bug in
xc_gntshr_munmap. I'd hazard a guess you are seeing the same thing.

Unfortunately those patches still had an outstanding issue and haven't
been applied yet.

Some message ids:
<517A5FE7.9050904@invisiblethingslab.com>
<20130508040327.91296310@duch.mimuw.edu.pl>
<20130508040327.951AD329@duch.mimuw.edu.pl>
and in particular the reason it isn't applied yet:
<518A57ED.5030708@tycho.nsa.gov>

Ian.