crit: do not crash on aarch64 doing 'crit x ./ rss'

Running 'crit x ./ rss' on aarch64 crashes with:

    File "/home/criu/crit/crit/__main__.py", line 331, in explore_rss
      while vmas[vmi]['start'] < pme:
            ~~~~^^^^^
  IndexError: list index out of range

This adds an additional check to the while loop to do access indexes out
of range.

Signed-off-by: Adrian Reber <[email protected]>

Author: adrianreber

crit/crit/__main__.py

@@ -323,12 +323,12 @@ def explore_rss(opts):
         pvmi = -1
         for pm in pms[1:]:
             pstr = '\t%lx / %-8d' % (pm['vaddr'], pm['nr_pages'])
-            while vmas[vmi]['end'] <= pm['vaddr']:
+            while vmi < len(vmas) and vmas[vmi]['end'] <= pm['vaddr']:
                 vmi += 1
 
             pme = pm['vaddr'] + (pm['nr_pages'] << 12)
             vstr = ''
-            while vmas[vmi]['start'] < pme:
+            while vmi < len(vmas) and vmas[vmi]['start'] < pme:
                 vma = vmas[vmi]
                 if vmi == pvmi:
                     vstr += ' ~'