user/sven/linux.git/include/linux/lockdep.h, branch v4.0

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

2014-10-13T13:51:40Z

Pull core locking updates from Ingo Molnar: "The main updates in this cycle were: - mutex MCS refactoring finishing touches: improve comments, refactor and clean up code, reduce debug data structure footprint, etc. - qrwlock finishing touches: remove old code, self-test updates. - small rwsem optimization - various smaller fixes/cleanups" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/lockdep: Revert qrwlock recusive stuff locking/rwsem: Avoid double checking before try acquiring write lock locking/rwsem: Move EXPORT_SYMBOL() lines to follow function definition locking/rwlock, x86: Delete unused asm/rwlock.h and rwlock.S locking/rwlock, x86: Clean up asm/spinlock*.h to remove old rwlock code locking/semaphore: Resolve some shadow warnings locking/selftest: Support queued rwlock locking/lockdep: Restrict the use of recursive read_lock() with qrwlock locking/spinlocks: Always evaluate the second argument of spin_lock_nested() locking/Documentation: Update locking/mutex-design.txt disadvantages locking/Documentation: Move locking related docs into Documentation/locking/ locking/mutexes: Use MUTEX_SPIN_ON_OWNER when appropriate locking/mutexes: Refactor optimistic spinning code locking/mcs: Remove obsolete comment locking/mutexes: Document quick lock release when unlocking locking/mutexes: Standardize arguments in lock/unlock slowpaths locking: Remove deprecated smp_mb__() barriers

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

2014-10-13T13:44:12Z

Pull RCU updates from Ingo Molnar: "The main changes in this cycle were: - changes related to No-CBs CPUs and NO_HZ_FULL - RCU-tasks implementation - torture-test updates - miscellaneous fixes - locktorture updates - RCU documentation updates" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (81 commits) workqueue: Use cond_resched_rcu_qs macro workqueue: Add quiescent state between work items locktorture: Cleanup header usage locktorture: Cannot hold read and write lock locktorture: Fix __acquire annotation for spinlock irq locktorture: Support rwlocks rcu: Eliminate deadlock between CPU hotplug and expedited grace periods locktorture: Document boot/module parameters rcutorture: Rename rcutorture_runnable parameter locktorture: Add test scenario for rwsem_lock locktorture: Add test scenario for mutex_lock locktorture: Make torture scripting account for new _runnable name locktorture: Introduce torture context locktorture: Support rwsems locktorture: Add infrastructure for torturing read locks torture: Address race in module cleanup locktorture: Make statistics generic locktorture: Teach about lock debugging locktorture: Support mutexes locktorture: Add documentation ...

locking/lockdep: Revert qrwlock recusive stuff

2014-10-03T04:09:30Z

Commit f0bab73cb539 ("locking/lockdep: Restrict the use of recursive read_lock() with qrwlock") changed lockdep to try and conform to the qrwlock semantics which differ from the traditional rwlock semantics. In particular qrwlock is fair outside of interrupt context, but in interrupt context readers will ignore all fairness. The problem modeling this is that read and write side have different lock state (interrupts) semantics but we only have a single representation of these. Therefore lockdep will get confused, thinking the lock can cause interrupt lock inversions. So revert it for now; the old rwlock semantics were already imperfectly modeled and the qrwlock extra won't fit either. If we want to properly fix this, I think we need to resurrect the work by Gautham did a few years ago that split the read and write state of locks: http://lwn.net/Articles/332801/ FWIW the locking selftest that would've failed (and was reported by Borislav earlier) is something like: RL(X1); /* IRQ-ON */ LOCK(A); UNLOCK(A); RU(X1); IRQ_ENTER(); RL(X1); /* IN-IRQ */ RU(X1); IRQ_EXIT(); At which point it would report that because A is an IRQ-unsafe lock we can suffer the following inversion: CPU0 CPU1 lock(A) lock(X1) lock(A) lock(X1) And this is 'wrong' because X1 can recurse (assuming the above lock are in fact read-lock) but lockdep doesn't know about this. Signed-off-by: Peter Zijlstra (Intel) Cc: Waiman Long Cc: ego@linux.vnet.ibm.com Cc: bp@alien8.de Cc: Linus Torvalds Cc: Paul E. McKenney Link: http://lkml.kernel.org/r/20140930132600.GA7444@worktop.programming.kicks-ass.net Signed-off-by: Ingo Molnar

locking: Add WARN_ON_ONCE lock assertion

2014-09-24T04:06:21Z

An interface may need to assert a lock invariant and not flood the system logs; add a lockdep helper macro equivalent to lockdep_assert_held() which only WARNs once. Signed-off-by: Peter Hurley Acked-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

rcu: Eliminate deadlock between CPU hotplug and expedited grace periods

2014-09-18T23:22:27Z

Currently, the expedited grace-period primitives do get_online_cpus(). This greatly simplifies their implementation, but means that calls to them holding locks that are acquired by CPU-hotplug notifiers (to say nothing of calls to these primitives from CPU-hotplug notifiers) can deadlock. But this is starting to become inconvenient, as can be seen here: https://lkml.org/lkml/2014/8/5/754. The problem in this case is that some developers need to acquire a mutex from a CPU-hotplug notifier, but also need to hold it across a synchronize_rcu_expedited(). As noted above, this currently results in deadlock. This commit avoids the deadlock and retains the simplicity by creating a try_get_online_cpus(), which returns false if the get_online_cpus() reference count could not immediately be incremented. If a call to try_get_online_cpus() returns true, the expedited primitives operate as before. If a call returns false, the expedited primitives fall back to normal grace-period operations. This falling back of course results in increased grace-period latency, but only during times when CPU hotplug operations are actually in flight. The effect should therefore be negligible during normal operation. Signed-off-by: Paul E. McKenney Cc: Josh Triplett Cc: "Rafael J. Wysocki" Tested-by: Lan Tianyu

locking/lockdep: Restrict the use of recursive read_lock() with qrwlock

2014-08-13T08:33:34Z

Unlike the original unfair rwlock implementation, queued rwlock will grant lock according to the chronological sequence of the lock requests except when the lock requester is in the interrupt context. Consequently, recursive read_lock calls will now hang the process if there is a write_lock call somewhere in between the read_lock calls. This patch updates the lockdep implementation to look for recursive read_lock calls. A new read state (3) is used to mark those read_lock call that cannot be recursively called except in the interrupt context. The new read state does exhaust the 2 bits available in held_lock:read bit field. The addition of any new read state in the future may require a redesign of how all those bits are squeezed together in the held_lock structure. Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra Cc: Maarten Lankhorst Cc: Rik van Riel Cc: Scott J Norton Cc: Fengguang Wu Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1407345722-61615-2-git-send-email-Waiman.Long@hp.com Signed-off-by: Ingo Molnar

locking/Documentation: Move locking related docs into Documentation/locking/

2014-08-13T08:32:03Z

Specifically: Documentation/locking/lockdep-design.txt Documentation/locking/lockstat.txt Documentation/locking/mutex-design.txt Documentation/locking/rt-mutex-design.txt Documentation/locking/rt-mutex.txt Documentation/locking/spinlocks.txt Documentation/locking/ww-mutex-design.txt Signed-off-by: Davidlohr Bueso Acked-by: Randy Dunlap Signed-off-by: Peter Zijlstra Cc: jason.low2@hp.com Cc: aswin@hp.com Cc: Alexei Starovoitov Cc: Al Viro Cc: Andrew Morton Cc: Chris Mason Cc: Dan Streetman Cc: David Airlie Cc: Davidlohr Bueso Cc: David S. Miller Cc: Greg Kroah-Hartman Cc: Heiko Carstens Cc: Jason Low Cc: Josef Bacik Cc: Kees Cook Cc: Linus Torvalds Cc: Lubomir Rintel Cc: Masanari Iida Cc: Paul E. McKenney Cc: Randy Dunlap Cc: Tim Chen Cc: Vineet Gupta Cc: fengguang.wu@intel.com Link: http://lkml.kernel.org/r/1406752916-3341-6-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar

Merge branch 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-03-31T21:13:25Z

Pull x86 LTO changes from Peter Anvin: "More infrastructure work in preparation for link-time optimization (LTO). Most of these changes is to make sure symbols accessed from assembly code are properly marked as visible so the linker doesn't remove them. My understanding is that the changes to support LTO are still not upstream in binutils, but are on the way there. This patchset should conclude the x86-specific changes, and remaining patches to actually enable LTO will be fed through the Kbuild tree (other than keeping up with changes to the x86 code base, of course), although not necessarily in this merge window" * 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits) Kbuild, lto: Handle basic LTO in modpost Kbuild, lto: Disable LTO for asm-offsets.c Kbuild, lto: Add a gcc-ld script to let run gcc as ld Kbuild, lto: add ld-version and ld-ifversion macros Kbuild, lto: Drop .number postfixes in modpost Kbuild, lto, workaround: Don't warn for initcall_reference in modpost lto: Disable LTO for sys_ni lto: Handle LTO common symbols in module loader lto, workaround: Add workaround for initcall reordering lto: Make asmlinkage __visible x86, lto: Disable LTO for the x86 VDSO initconst, x86: Fix initconst mistake in ts5500 code initconst: Fix initconst mistake in dcdbas asmlinkage: Make trace_hardirqs_on/off_caller visible asmlinkage, x86: Fix 32bit memcpy for LTO asmlinkage Make __stack_chk_failed and memcmp visible asmlinkage: Mark rwsem functions that can be called from assembler asmlinkage asmlinkage: Make main_extable_sort_needed visible asmlinkage, mutex: Mark __visible asmlinkage: Make trace_hardirq visible ...

asmlinkage: Make lockdep_sys_exit asmlinkage

2014-02-14T02:12:54Z

lockdep_sys_exit can be called from assembler code, so make it asmlinkage. Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-5-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin

lockdep: Change lockdep_set_novalidate_class() to use _and_name

2014-02-09T20:19:01Z

Cosmetic. This doesn't really matter because a) device->mutex is the only user of __lockdep_no_validate__ and b) this class should be never reported as the source of problem, but if something goes wrong "&dev->mutex" looks better than "&__lockdep_no_validate__" as the name of the lock. Signed-off-by: Oleg Nesterov Cc: Dave Jones Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Paul McKenney Cc: Steven Rostedt Cc: Alan Stern Cc: Sasha Levin Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20140120182016.GA26512@redhat.com Signed-off-by: Ingo Molnar