none/tests/amd64/nibz_bennee_mmap.c

   1
   2 /* Test for aspacem bug reported by Alex Bennee, reported on users
   3    list around 9 Aug 06, resulting in
   4
   5    > > --1515:0:aspacem  Valgrind: FATAL: aspacem assertion failed:
   6    > > --1515:0:aspacem    holeEnd <= aspacem_maxAddr
   7    > > --1515:0:aspacem    at m_aspacemgr/aspacemgr.c:1998
   8    > > (vgPlain_am_get_advisory)
   9    > > --1515:0:aspacem  Exiting now.
  10
  11    TomH writes:
  12
  13    > I think the problem here is that you've done an mmap (either fixed or
  14    > hinted) above aspacem_maxAddr and then munmaped it which leaves you
  15    > with a free segment above aspacem_maxAddr.
  16
  17    The sequence seems to be that you have to allocate memory somewhere
  18    above aspacem_maxAddr, then free it, then do another hinted
  19    allocation that is above aspacem_maxAddr but which can't be done
  20    due to the memory already being in use. This program will reproduce
  21    it.
  22
  23    On investigation: the problem was the munmap returns its space in
  24    the form of SkFree even though the space above aspacem_maxAddr is
  25    supposed to be SkResvn.  This is now fixed.
  26 */
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include "tests/sys_mman.h"
  31
  32 int main(int argc, char **argv)
  33 {
  34    void *p;
  35    if ((p = mmap((void*)0x1F7F100000, 4096, PROT_READ|PROT_WRITE,
  36                  MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0)) == (void *)-1)
  37    {
  38       perror("mmap");
  39       exit(1);
  40    }
  41    if (munmap(p, 4096) < 0)
  42    {
  43       perror("munmap");
  44       exit(1);
  45    }
  46    if ((p = mmap((void*)0x1F7F101000, 4096, PROT_READ,
  47                  MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)) == (void *)-1)
  48    {
  49       perror("mmap");
  50       exit(1);
  51    }
  52    if ((p = mmap((void*)0x1F7F101000, 4096, PROT_READ,
  53                  MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)) == (void *)-1)
  54    {
  55       perror("mmap");
  56       exit(1);
  57    }
  58
  59    printf("made it through alive!\n");
  60    exit(0);
  61 }