Possible bug in arch/i386/kernel/process.c for reloading of debug registers (DRx)?

[Kevin Lawton]

I was scanning through the source and noticed the lines below.
Should the code below, be reloading at least the local bits of
DR7 if the current DR7 value != 0?  From a quick glance, it
looks like only if the next task's DR7 value is non-zero,
that DR7 is reloaded.  I'm wondering if this would leave
a new task to receive "local" debug events for the previous
task if prev->DR7!=0 && next->DR7==0.

-Kevin

linux-2.5.59: arch/i386/kernel/process.c: line 462+:

  /*
   * Now maybe reload the debug registers
   */
  if (unlikely(next->debugreg[7])) {
    loaddebug(next, 0);
    loaddebug(next, 1);
    loaddebug(next, 2);
    loaddebug(next, 3);
    /* no 4 and 5 */
    loaddebug(next, 6);
    loaddebug(next, 7);
  }

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