1. 07 Jun, 2014 1 commit
    • Thomas Gleixner's avatar
      futex: Add another early deadlock detection check · efcd089d
      Thomas Gleixner authored
      commit 866293ee upstream.
      
      Dave Jones trinity syscall fuzzer exposed an issue in the deadlock
      detection code of rtmutex:
        http://lkml.kernel.org/r/20140429151655.GA14277@redhat.com
      
      That underlying issue has been fixed with a patch to the rtmutex code,
      but the futex code must not call into rtmutex in that case because
          - it can detect that issue early
          - it avoids a different and more complex fixup for backing out
      
      If the user space variable got manipulated to 0x80000000 which means
      no lock holder, but the waiters bit set and an active pi_state in the
      kernel is found we can figure out the recursive locking issue by
      looking at the pi_state owner. If that is the current task, then we
      can safely return -EDEADLK.
      
      The check should have been added in commit 59fa6245 (futex: Handle
      futex_pi OWNER_DIED take over correctly) already, but I did not see
      the above issue caused by user space manipulation back then.
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Dave Jones <davej@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Darren Hart <darren@dvhart.com>
      Cc: Davidlohr Bueso <davidlohr@hp.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Clark Williams <williams@redhat.com>
      Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
      Cc: Roland McGrath <roland@hack.frob.com>
      Cc: Carlos ODonell <carlos@redhat.com>
      Cc: Jakub Jelinek <jakub@redhat.com>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
      Link: http://lkml.kernel.org/r/20140512201701.097349971@linutronix.deSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      efcd089d
  2. 31 May, 2014 39 commits