1. 14 Feb, 2008 39 commits
  2. 13 Feb, 2008 1 commit
    • Peter Zijlstra's avatar
      xtime_lock vs update_process_times · aa02cd2d
      Peter Zijlstra authored
      Commit d3d74453 ("hrtimer: fixup the
      HRTIMER_CB_IRQSAFE_NO_SOFTIRQ fallback") broke several archs, and since
      only Russell bothered to merge the fix, and Greg to ACK his arch, I'm
      sending this for merger.
      
      I have confirmation that the Alpha bit results in a booting kernel.
      That leaves: blackfin, frv, sh and sparc untested.
      
      The deadlock in question was found by Russell:
      
        IRQ handle
          -> timer_tick() - xtime seqlock held for write
            -> update_process_times()
              -> run_local_timers()
                -> hrtimer_run_queues()
                  -> hrtimer_get_softirq_time() - tries to get a read lock
      
      Now, Thomas assures me the fix is trivial, only do_timer() needs to be
      done under the xtime_lock, and update_process_times() can savely be
      removed from under it.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: default avatarGreg Ungerer <gerg@uclinux.org>
      CC: Richard Henderson <rth@twiddle.net>
      CC: Bryan Wu <bryan.wu@analog.com>
      CC: David Howells <dhowells@redhat.com>
      CC: Paul Mundt <lethal@linux-sh.org>
      CC: William Irwin <wli@holomorphy.com>
      Acked-by: default avatarIngo Molnar <mingo@elte.hu>
      Acked-by: default avatarIvan Kokshaysky <ink@jurassic.park.msu.ru>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      aa02cd2d