1. 16 11月, 2012 1 次提交
    • O
      uprobes: Use percpu_rw_semaphore to fix register/unregister vs dup_mmap() race · 32cdba1e
      Oleg Nesterov 提交于
      This was always racy, but 26872090
      "uprobes: Rework register_for_each_vma() to make it O(n)" should be
      blamed anyway, it made everything worse and I didn't notice.
      
      register/unregister call build_map_info() and then do install/remove
      breakpoint for every mm which mmaps inode/offset. This can obviously
      race with fork()->dup_mmap() in between and we can miss the child.
      
      uprobe_register() could be easily fixed but unregister is much worse,
      the new mm inherits "int3" from parent and there is no way to detect
      this if uprobe goes away.
      
      So this patch simply adds percpu_down_read/up_read around dup_mmap(),
      and percpu_down_write/up_write into register_for_each_vma().
      
      This adds 2 new hooks into dup_mmap() but we can kill uprobe_dup_mmap()
      and fold it into uprobe_end_dup_mmap().
      Reported-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
      Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      32cdba1e
  2. 15 11月, 2012 1 次提交
  3. 04 11月, 2012 4 次提交
  4. 25 10月, 2012 14 次提交
  5. 24 10月, 2012 20 次提交