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  1. 14 Oct, 2009 1 commit
    • Darren Hart's avatar
      futex: Check for NULL keys in match_futex · 2bc87203
      Darren Hart authored 
      If userspace tries to perform a requeue_pi on a non-requeue_pi waiter,
it will find the futex_q->requeue_pi_key to be NULL and OOPS.

Check for NULL in match_futex() instead of doing explicit NULL pointer
checks on all call sites.  While match_futex(NULL, NULL) returning
false is a little odd, it's still correct as we expect valid key
references.
Signed-off-by: default avatarDarren Hart <dvhltc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Dinakar Guniguntala <dino@in.ibm.com>
CC: John Stultz <johnstul@us.ibm.com>
Cc: stable@kernel.org
LKML-Reference: <4AD60687.10306@us.ibm.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      2bc87203
  3. 13 Oct, 2009 1 commit
    • Thomas Gleixner's avatar
      futex: Handle spurious wake up · d58e6576
      Thomas Gleixner authored 
      The futex code does not handle spurious wake up in futex_wait and
futex_wait_requeue_pi.

The code assumes that any wake up which was not caused by futex_wake /
requeue or by a timeout was caused by a signal wake up and returns one
of the syscall restart error codes.

In case of a spurious wake up the signal delivery code which deals
with the restart error codes is not invoked and we return that error
code to user space. That causes applications which actually check the
return codes to fail. Blaise reported that on preempt-rt a python test
program run into a exception trap. -rt exposed that due to a built in
spurious wake up accelerator :)

Solve this by checking signal_pending(current) in the wake up path and
handle the spurious wake up case w/o returning to user space.
Reported-by: default avatarBlaise Gassend <blaise@willowgarage.com>
Debugged-by: default avatarDarren Hart <dvhltc@us.ibm.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@kernel.org
LKML-Reference: <new-submission>
      d58e6576
  5. 12 Oct, 2009 1 commit
  7. 09 Oct, 2009 3 commits
  9. 08 Oct, 2009 34 commits