1. 13 1月, 2009 1 次提交
    • A
      x86: avoid theoretical vmalloc fault loop · f313e123
      Andi Kleen 提交于
      Ajith Kumar noticed:
      
       I was going through the vmalloc fault handling for x86_64 and am unclear
       about the following lines in the vmalloc_fault() function.
      
       pgd = pgd_offset(current->mm ?: &init_mm, address);
       pgd_ref = pgd_offset_k(address);
      
       Here the intention is to get the pgd corresponding to the current process
       and sync it up with the pgd in init_mm(obtained from pgd_offset_k).
       However, for kernel threads current->mm is NULL and hence pgd =
       pgd_offset(init_mm, address) = pgd_ref which means the fault handler
       returns without setting the pgd entry in the MM structure in the context
       of which the kernel thread has faulted.  This could lead to never-ending
       faults and busy looping of kernel threads like pdflush.  So, shouldn't the
       pgd = pgd_offset(current->mm ?: &init_mm, address); be pgd =
       pgd_offset(current->active_mm ?: &init_mm, address);
      
      We can use active_mm unconditionally because it should be always set.
      Signed-off-by: NAndi Kleen <ak@linux.intel.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      f313e123
  2. 11 1月, 2009 5 次提交
  3. 10 1月, 2009 34 次提交