linux/kernel/locking, branch v4.11

sparc64: Use LOCKDEP_SMALL, not PROVE_LOCKING_SMALL

2017-04-18T20:11:07Z

CONFIG_PROVE_LOCKING_SMALL shrinks the memory usage of lockdep so the kernel text, data, and bss fit in the required 32MB limit, but this option is not set for every config that enables lockdep. A 4.10 kernel fails to boot with the console output Kernel: Using 8 locked TLB entries for main kernel image. hypervisor_tlb_lock[2000000:0:8000000071c007c3:1]: errors with f Program terminated with these config options CONFIG_LOCKDEP=y CONFIG_LOCK_STAT=y CONFIG_PROVE_LOCKING=n To fix, rename CONFIG_PROVE_LOCKING_SMALL to CONFIG_LOCKDEP_SMALL, and enable this option with CONFIG_LOCKDEP=y so we get the reduced memory usage every time lockdep is turned on. Tested that CONFIG_LOCKDEP_SMALL is set to 'y' if and only if CONFIG_LOCKDEP is set to 'y'. When other lockdep-related config options that select CONFIG_LOCKDEP are enabled (e.g. CONFIG_LOCK_STAT or CONFIG_PROVE_LOCKING), verified that CONFIG_LOCKDEP_SMALL is also enabled. Fixes: e6b5f1be7afe ("config: Adding the new config parameter CONFIG_PROVE_LOCKING_SMALL for sparc") Signed-off-by: Daniel Jordan Reviewed-by: Babu Moger Signed-off-by: David S. Miller

locking/rwsem: Fix down_write_killable() for CONFIG_RWSEM_GENERIC_SPINLOCK=y

2017-03-16T08:28:30Z

We hang if SIGKILL has been sent, but the task is stuck in down_read() (after do_exit()), even though no task is doing down_write() on the rwsem in question: INFO: task libupnp:21868 blocked for more than 120 seconds. libupnp D 0 21868 1 0x08100008 ... Call Trace: __schedule() schedule() __down_read() do_exit() do_group_exit() __wake_up_parent() This bug has already been fixed for CONFIG_RWSEM_XCHGADD_ALGORITHM=y in the following commit: 04cafed7fc19 ("locking/rwsem: Fix down_write_killable()") ... however, this bug also exists for CONFIG_RWSEM_GENERIC_SPINLOCK=y. Signed-off-by: Niklas Cassel Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Andrew Morton Cc: Linus Torvalds Cc: Niklas Cassel Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: d47996082f52 ("locking/rwsem: Introduce basis for down_write_killable()") Link: http://lkml.kernel.org/r/1487981873-12649-1-git-send-email-niklass@axis.com Signed-off-by: Ingo Molnar

Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-03-07T22:33:11Z

Pull locking fixes from Ingo Molnar: - Change the new refcount_t warnings from WARN() to WARN_ONCE() - two ww_mutex fixes - plus a new lockdep self-consistency check for a bug that triggered in practice * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/ww_mutex: Adjust the lock number for stress test locking/lockdep: Add nest_lock integrity test locking/ww_mutex: Replace cpu_relax() with cond_resched() for tests locking/refcounts: Change WARN() to WARN_ONCE()

locking/ww_mutex: Adjust the lock number for stress test

2017-03-02T08:00:39Z

Because there are only 12 bits in held_lock::references, so we only support 4095 nested lock held in the same time, adjust the lock number for ww_mutex stress test to kill one lockdep splat: [ ] [ BUG: bad unlock balance detected! ] [ ] kworker/u2:0/5 is trying to release lock (ww_class_mutex) at: [ ] ww_mutex_unlock() [ ] but there are no more locks to release! ... Signed-off-by: Boqun Feng Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Chris Wilson Cc: Fengguang Wu Cc: Linus Torvalds Cc: Nicolai Hähnle Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170301150138.hdixnmafzfsox7nn@tardis.cn.ibm.com Signed-off-by: Ingo Molnar

locking/lockdep: Add nest_lock integrity test

2017-03-02T08:00:38Z

Boqun reported that hlock->references can overflow. Add a debug test for that to generate a clear error when this happens. Without this, lockdep is likely to report a mysterious failure on unlock. Reported-by: Boqun Feng Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Chris Wilson Cc: Linus Torvalds Cc: Nicolai Hähnle Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

locking/ww_mutex: Replace cpu_relax() with cond_resched() for tests

2017-03-02T08:00:38Z

When busy-spinning on a ww_mutex_trylock(), we depend upon the other thread advancing and releasing the lock. This can not happen on a single CPU unless we relinquish it: [ ] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [kworker/0:1:18] ... [ ] Call Trace: [ ] mutex_trylock() [ ] test_mutex_work+0x31/0x56 [ ] process_one_work+0x1b4/0x2f9 [ ] worker_thread+0x1b0/0x27c [ ] kthread+0xd1/0xd3 [ ] ret_from_fork+0x19/0x30 Reported-by: Fengguang Wu Signed-off-by: Chris Wilson Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: f2a5fec17395 ("locking/ww_mutex: Begin kselftests for ww_mutex") Link: http://lkml.kernel.org/r/20170228094011.2595-1-chris@chris-wilson.co.uk Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:35Z

We are going to split out of , which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder file that just maps to to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:34Z

sched/headers: Prepare to move signal wakeup & sigpending methods from into

2017-03-02T07:42:32Z

Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

sched/headers: Prepare for the removal of from

2017-03-02T07:42:32Z

Fix up missing #includes in other places that rely on sched.h doing that for them. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar