futex: Acknowledge a new waiter in counter before plist
authorDavidlohr Bueso <dave@stgolabs.net>
Thu, 21 Apr 2016 03:09:24 +0000 (20:09 -0700)
committerThomas Gleixner <tglx@linutronix.de>
Thu, 21 Apr 2016 09:06:09 +0000 (11:06 +0200)
commitfe1bce9e2107ba3a8faffe572483b6974201a0e6
treec7f1a4b8ab31d63aa79a7e130f8a65bbebfd3269
parent89e9e66ba1b3bde9d8ea90566c2aee20697ad681
futex: Acknowledge a new waiter in counter before plist

Otherwise an incoming waker on the dest hash bucket can miss
the waiter adding itself to the plist during the lockless
check optimization (small window but still the correct way
of doing this); similarly to the decrement counterpart.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: bigeasy@linutronix.de
Cc: dvhart@infradead.org
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1461208164-29150-1-git-send-email-dave@stgolabs.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
kernel/futex.c