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* lockdep: fix oops in processing workqueuePeter Zijlstra2012-05-151-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Under memory load, on x86_64, with lockdep enabled, the workqueue's process_one_work() has been seen to oops in __lock_acquire(), barfing on a 0xffffffff00000000 pointer in the lockdep_map's class_cache[]. Because it's permissible to free a work_struct from its callout function, the map used is an onstack copy of the map given in the work_struct: and that copy is made without any locking. Surprisingly, gcc (4.5.1 in Hugh's case) uses "rep movsl" rather than "rep movsq" for that structure copy: which might race with a workqueue user's wait_on_work() doing lock_map_acquire() on the source of the copy, putting a pointer into the class_cache[], but only in time for the top half of that pointer to be copied to the destination map. Boom when process_one_work() subsequently does lock_map_acquire() on its onstack copy of the lockdep_map. Fix this, and a similar instance in call_timer_fn(), with a lockdep_copy_map() function which additionally NULLs the class_cache[]. Note: this oops was actually seen on 3.4-next, where flush_work() newly does the racing lock_map_acquire(); but Tejun points out that 3.4 and earlier are already vulnerable to the same through wait_on_work(). * Patch orginally from Peter. Hugh modified it a bit and wrote the description. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Reported-by: Hugh Dickins <hughd@google.com> LKML-Reference: <alpine.LSU.2.00.1205070951170.1544@eggly.anvils> Signed-off-by: Tejun Heo <tj@kernel.org>
* printk, lockdep: Disable lock debugging on zap_locks()Peter Zijlstra2011-11-141-0/+4
| | | | | | | | | | | | | zap_locks() is used by printk() in a last ditch effort to get data out, clearly we cannot trust lock state after this so make it disable lock debugging. Also don't treat printk recursion through lockdep as a normal recursion bug but try hard to get the lockdep splat out. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-kqxwmo4xz37e1s8w0xopvr0q@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* rcu: Restore checks for blocking in RCU read-side critical sectionsPaul E. McKenney2011-09-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Long ago, using TREE_RCU with PREEMPT would result in "scheduling while atomic" diagnostics if you blocked in an RCU read-side critical section. However, PREEMPT now implies TREE_PREEMPT_RCU, which defeats this diagnostic. This commit therefore adds a replacement diagnostic based on PROVE_RCU. Because rcu_lockdep_assert() and lockdep_rcu_dereference() are now being used for things that have nothing to do with rcu_dereference(), rename lockdep_rcu_dereference() to lockdep_rcu_suspicious() and add a third argument that is a string indicating what is suspicious. This third argument is passed in from a new third argument to rcu_lockdep_assert(). Update all calls to rcu_lockdep_assert() to add an informative third argument. Also, add a pair of rcu_lockdep_assert() calls from within rcu_note_context_switch(), one complaining if a context switch occurs in an RCU-bh read-side critical section and another complaining if a context switch occurs in an RCU-sched read-side critical section. These are present only if the PROVE_RCU kernel parameter is enabled. Finally, fix some checkpatch whitespace complaints in lockdep.c. Again, you must enable PROVE_RCU to see these new diagnostics. But you are enabling PROVE_RCU to check out new RCU uses in any case, aren't you? Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* lockdep, mutex: provide mutex_lock_nest_lockPeter Zijlstra2011-05-251-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to convert i_mmap_lock to a mutex we need a mutex equivalent to spin_lock_nest_lock(), thus provide the mutex_lock_nest_lock() annotation. As with spin_lock_nest_lock(), mutex_lock_nest_lock() allows annotation of the locking pattern where an outer lock serializes the acquisition order of nested locks. That is, if every time you lock multiple locks A, say A1 and A2 you first acquire N, the order of acquiring A1 and A2 is irrelevant. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Tony Luck <tony.luck@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'fixes-2.6.38' of ↵Linus Torvalds2011-01-211-0/+3
|\ | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq * 'fixes-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: note the nested NOT_RUNNING test in worker_clr_flags() isn't a noop workqueue: relax lockdep annotation on flush_work()
| * workqueue: relax lockdep annotation on flush_work()Tejun Heo2011-01-111-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the lockdep annotation in flush_work() requires exclusive access on the workqueue the target work is queued on and triggers warning if a work is trying to flush another work on the same workqueue; however, this is no longer true as workqueues can now execute multiple works concurrently. This patch adds lock_map_acquire_read() and make process_one_work() hold read access to the workqueue while executing a work and start_flush_work() check for write access if concurrnecy level is one or the workqueue has a rescuer (as only one execution resource - the rescuer - is guaranteed to be available under memory pressure), and read access if higher. This better represents what's going on and removes spurious lockdep warnings which are triggered by fake dependency chain created through flush_work(). * Peter pointed out that flushing another work from a WQ_MEM_RECLAIM wq breaks forward progress guarantee under memory pressure. Condition check accordingly updated. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: "Rafael J. Wysocki" <rjw@sisk.pl> Tested-by: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@kernel.org
* | lockdep: Move early boot local IRQ enable/disable status to init/main.cTejun Heo2011-01-201-8/+0
|/ | | | | | | | | | | | | | | | | | | | | | During early boot, local IRQ is disabled until IRQ subsystem is properly initialized. During this time, no one should enable local IRQ and some operations which usually are not allowed with IRQ disabled, e.g. operations which might sleep or require communications with other processors, are allowed. lockdep tracked this with early_boot_irqs_off/on() callbacks. As other subsystems need this information too, move it to init/main.c and make it generally available. While at it, toggle the boolean to early_boot_irqs_disabled instead of enabled so that it can be initialized with %false and %true indicates the exceptional condition. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <20110120110635.GB6036@htj.dyndns.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'irq-core-for-linus' of ↵Linus Torvalds2010-10-211-8/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (96 commits) apic, x86: Use BIOS settings for IBS and MCE threshold interrupt LVT offsets apic, x86: Check if EILVT APIC registers are available (AMD only) x86: ioapic: Call free_irte only if interrupt remapping enabled arm: Use ARCH_IRQ_INIT_FLAGS genirq, ARM: Fix boot on ARM platforms genirq: Fix CONFIG_GENIRQ_NO_DEPRECATED=y build x86: Switch sparse_irq allocations to GFP_KERNEL genirq: Switch sparse_irq allocator to GFP_KERNEL genirq: Make sparse_lock a mutex x86: lguest: Use new irq allocator genirq: Remove the now unused sparse irq leftovers genirq: Sanitize dynamic irq handling genirq: Remove arch_init_chip_data() x86: xen: Sanitise sparse_irq handling x86: Use sane enumeration x86: uv: Clean up the direct access to irq_desc x86: Make io_apic.c local functions static genirq: Remove irq_2_iommu x86: Speed up the irq_remapped check in hot pathes intr_remap: Simplify the code further ... Fix up trivial conflicts in arch/x86/Kconfig
| * genirq: Remove early_init_irq_lock_class()Thomas Gleixner2010-10-121-8/+0
| | | | | | | | | | | | | | | | | | | | early_init_irq_lock_class() is called way before anything touches the irq descriptors. In case of SPARSE_IRQ=y this is a NOP operation because the radix tree is empty at this point. For the SPARSE_IRQ=n case it's sufficient to set the lock class in early_init_irq(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@elte.hu>
* | lockdep: Add improved subclass cachingHitoshi Mitake2010-10-181-1/+12
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current lockdep_map only caches one class with subclass == 0, and looks up hash table of classes when subclass != 0. It seems that this has no problem because the case of subclass != 0 is rare. But locks of struct rq are acquired with subclass == 1 when task migration is executed. Task migration is high frequent event, so I modified lockdep to cache subclasses. I measured the score of perf bench sched messaging. This patch has slightly but certain (order of milli seconds or 10 milli seconds) effect when lots of tasks are running. I'll show the result in the tail of this description. NR_LOCKDEP_CACHING_CLASSES specifies how many classes can be cached in the instances of lockdep_map. I discussed with Peter Zijlstra in LinuxCon Japan about this approach and he taught me that caching every subclasses(8) is cleary waste of memory. So number of cached classes should be configurable. === Score comparison of benchmarks === # "min" means best score, and "max" means worst score for i in `seq 1 10`; do ./perf bench -f simple sched messaging; done before: min: 0.565000, max: 0.583000, avg: 0.572500 after: min: 0.559000, max: 0.568000, avg: 0.563300 # with more processes for i in `seq 1 10`; do ./perf bench -f simple sched messaging -g 40; done before: min: 2.274000, max: 2.298000, avg: 2.286300 after: min: 2.242000, max: 2.270000, avg: 2.259700 Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1286269311-28336-2-git-send-email-mitake@dcl.info.waseda.ac.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Add novalidate class for dev->mutex conversionPeter Zijlstra2010-05-211-0/+8
| | | | | | | | | | | | | | | | The conversion of device->sem to device->mutex resulted in lockdep warnings. Create a novalidate class for now until the driver folks come up with separate classes. That way we have at least the basic mutex debugging coverage. Add a checkpatch error so the usage is reserved for device->mutex. [ tglx: checkpatch and compile fix for LOCKDEP=n ] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysctl extern cleanup: lockdepDave Young2010-03-121-0/+4
| | | | | | | | | | | | | | Extern declarations in sysctl.c should be moved to their own header file, and then include them in relavant .c files. Move lockdep extern declarations to linux/lockdep.h Signed-off-by: Dave Young <hidave.darkstar@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* rcu: Integrate rcu_dereference_check() message into lockdepPaul E. McKenney2010-02-251-0/+4
| | | | | | | | | | | | | | | | | | | Make rcu_dereference_check() print the list of held locks in addition to the stack dump to ease debugging. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-3-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Reintroduce generation count to make BFS fasterMing Lei2009-08-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We still can apply DaveM's generation count optimization to BFS, based on the following idea: - before doing each BFS, increase the global generation id by 1 - if one node in the graph has been visited, mark it as visited by storing the current global generation id into the node's dep_gen_id field - so we can decide if one node has been visited already, by comparing the node's dep_gen_id with the global generation id. By applying DaveM's generation count optimization to current implementation of BFS, we gain the following advantages: - we save MAX_LOCKDEP_ENTRIES/8 bytes memory; - we remove the bitmap_zero(bfs_accessed, MAX_LOCKDEP_ENTRIES); in each BFS, which is very time-consuming since MAX_LOCKDEP_ENTRIES may be very large.(16384UL) Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "David S. Miller" <davem@davemloft.net> LKML-Reference: <1248274089-6358-1-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Deal with many similar locksPeter Zijlstra2009-08-021-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | spin_lock_nest_lock() allows to take many instances of the same class, this can easily lead to overflow of MAX_LOCK_DEPTH. To avoid this overflow, we'll stop accounting instances but start reference counting the class in the held_lock structure. [ We could maintain a list of instances, if we'd move the hlock stuff into __lock_acquired(), but that would require significant modifications to the current code. ] We restrict this mode to spin_lock_nest_lock() only, because it degrades the lockdep quality due to lost of instance. For lockstat this means we don't track lock statistics for any but the first lock in the series. Currently nesting is limited to 11 bits because that was the spare space available in held_lock. This yields a 2048 instances maximium. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Introduce lockdep_assert_held()Peter Zijlstra2009-08-021-0/+8
| | | | | | | | Add a lockdep helper to validate that we indeed are the owner of a lock. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: BFS cleanupPeter Zijlstra2009-07-241-4/+3
| | | | | | | | | | | | | | Some cleanups of the lockdep code after the BFS series: - Remove the last traces of the generation id - Fixup comment style - Move the bfs routines into lockdep.c - Cleanup the bfs routines [ tom.leiming@gmail.com: Fix crash ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-11-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Print the shortest dependency chain if finding a circleMing Lei2009-07-241-0/+6
| | | | | | | | | | | | | | | | | | | | | Currently lockdep will print the 1st circle detected if it exists when acquiring a new (next) lock. This patch prints the shortest path from the next lock to be acquired to the previous held lock if a circle is found. The patch still uses the current method to check circle, and once the circle is found, breadth-first search algorithem is used to compute the shortest path from the next lock to the previous lock in the forward lock dependency graph. Printing the shortest path will shorten the dependency chain, and make troubleshooting for possible circular locking easier. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-2-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* vfs: Set special lockdep map for dirs only if not set by fsJan Kara2009-06-221-0/+15
| | | | | | | | | | | | | | | | Some filesystems need to set lockdep map for i_mutex differently for different directories. For example OCFS2 has system directories (for orphan inode tracking and for gathering all system files like journal or quota files into a single place) which have different locking locking rules than standard directories. For a filesystem setting lockdep map is naturaly done when the inode is read but we have to modify unlock_new_inode() not to overwrite the lockdep map the filesystem has set. Acked-by: peterz@infradead.org CC: mingo@redhat.com Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Joel Becker <joel.becker@oracle.com>
* Factor out #ifdefs from kernel/spinlock.c to LOCK_CONTENDED_FLAGSRobin Holt2009-04-021-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | SGI has observed that on large systems, interrupts are not serviced for a long period of time when waiting for a rwlock. The following patch series re-enables irqs while waiting for the lock, resembling the code which is already there for spinlocks. I only made the ia64 version, because the patch adds some overhead to the fast path. I assume there is currently no demand to have this for other architectures, because the systems are not so large. Of course, the possibility to implement raw_{read|write}_lock_flags for any architecture is still there. This patch: The new macro LOCK_CONTENDED_FLAGS expands to the correct implementation depending on the config options, so that IRQ's are re-enabled when possible, but they remain disabled if CONFIG_LOCKDEP is set. Signed-off-by: Petr Tesarik <ptesarik@suse.cz> Signed-off-by: Robin Holt <holt@sgi.com> Cc: <linux-arch@vger.kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lockdep: move state bit definitions aroundPeter Zijlstra2009-02-141-45/+4
| | | | | | | For convenience later. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: sanitize reclaim bit namesPeter Zijlstra2009-02-141-4/+4
| | | | | | | | | s/HELD_OVER/ENABLED/g so that its similar to the hard and soft-irq names. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: sanitize bit namesPeter Zijlstra2009-02-141-11/+11
| | | | | | | | | s/\(LOCKF\?_ENABLED_[^ ]*\)S\(_READ\)\?\>/\1\2/g So that the USED_IN and ENABLED have the same names. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: annotate reclaim context (__GFP_NOFS)Nick Piggin2009-02-141-1/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here is another version, with the incremental patch rolled up, and added reclaim context annotation to kswapd, and allocation tracing to slab allocators (which may only ever reach the page allocator in rare cases, so it is good to put annotations here too). Haven't tested this version as such, but it should be getting closer to merge worthy ;) -- After noticing some code in mm/filemap.c accidentally perform a __GFP_FS allocation when it should not have been, I thought it might be a good idea to try to catch this kind of thing with lockdep. I coded up a little idea that seems to work. Unfortunately the system has to actually be in __GFP_FS page reclaim, then take the lock, before it will mark it. But at least that might still be some orders of magnitude more common (and more debuggable) than an actual deadlock condition, so we have some improvement I hope (the concept is no less complete than discovery of a lock's interrupt contexts). I guess we could even do the same thing with __GFP_IO (normal reclaim), and even GFP_NOIO locks too... but filesystems will have the most locks and fiddly code paths, so let's start there and see how it goes. It *seems* to work. I did a quick test. ================================= [ INFO: inconsistent lock state ] 2.6.28-rc6-00007-ged31348-dirty #26 --------------------------------- inconsistent {in-reclaim-W} -> {ov-reclaim-W} usage. modprobe/8526 [HC0[0]:SC0[0]:HE1:SE1] takes: (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd] {in-reclaim-W} state was registered at: [<ffffffff80267bdb>] __lock_acquire+0x75b/0x1a60 [<ffffffff80268f71>] lock_acquire+0x91/0xc0 [<ffffffff8070f0e1>] mutex_lock_nested+0xb1/0x310 [<ffffffffa002002b>] brd_init+0x2b/0x216 [brd] [<ffffffff8020903b>] _stext+0x3b/0x170 [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0 [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff irq event stamp: 3929 hardirqs last enabled at (3929): [<ffffffff8070f2b5>] mutex_lock_nested+0x285/0x310 hardirqs last disabled at (3928): [<ffffffff8070f089>] mutex_lock_nested+0x59/0x310 softirqs last enabled at (3732): [<ffffffff8061f623>] sk_filter+0x83/0xe0 softirqs last disabled at (3730): [<ffffffff8061f5b6>] sk_filter+0x16/0xe0 other info that might help us debug this: 1 lock held by modprobe/8526: #0: (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd] stack backtrace: Pid: 8526, comm: modprobe Not tainted 2.6.28-rc6-00007-ged31348-dirty #26 Call Trace: [<ffffffff80265483>] print_usage_bug+0x193/0x1d0 [<ffffffff80266530>] mark_lock+0xaf0/0xca0 [<ffffffff80266735>] mark_held_locks+0x55/0xc0 [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd] [<ffffffff802667ca>] trace_reclaim_fs+0x2a/0x60 [<ffffffff80285005>] __alloc_pages_internal+0x475/0x580 [<ffffffff8070f29e>] ? mutex_lock_nested+0x26e/0x310 [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd] [<ffffffffa002006a>] brd_init+0x6a/0x216 [brd] [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd] [<ffffffff8020903b>] _stext+0x3b/0x170 [<ffffffff8070f8b9>] ? mutex_unlock+0x9/0x10 [<ffffffff8070f83d>] ? __mutex_unlock_slowpath+0x10d/0x180 [<ffffffff802669ec>] ? trace_hardirqs_on_caller+0x12c/0x190 [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0 [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'irq-core-for-linus' of ↵Linus Torvalds2008-12-301-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, sparseirq: clean up Kconfig entry x86: turn CONFIG_SPARSE_IRQ off by default sparseirq: fix numa_migrate_irq_desc dependency and comments sparseirq: add kernel-doc notation for new member in irq_desc, -v2 locking, irq: enclose irq_desc_lock_class in CONFIG_LOCKDEP sparseirq, xen: make sure irq_desc is allocated for interrupts sparseirq: fix !SMP building, #2 x86, sparseirq: move irq_desc according to smp_affinity, v7 proc: enclose desc variable of show_stat() in CONFIG_SPARSE_IRQ sparse irqs: add irqnr.h to the user headers list sparse irqs: handle !GENIRQ platforms sparseirq: fix !SMP && !PCI_MSI && !HT_IRQ build sparseirq: fix Alpha build failure sparseirq: fix typo in !CONFIG_IO_APIC case x86, MSI: pass irq_cfg and irq_desc x86: MSI start irq numbering from nr_irqs_gsi x86: use NR_IRQS_LEGACY sparse irq_desc[] array: core kernel and x86 changes genirq: record IRQ_LEVEL in irq_desc[] irq.h: remove padding from irq_desc on 64bits
| * locking, irq: enclose irq_desc_lock_class in CONFIG_LOCKDEPKOSAKI Motohiro2008-12-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: simplify code commit "08678b0: generic: sparse irqs: use irq_desc() [...]" introduced the irq_desc_lock_class variable. But it is used only if CONFIG_SPARSE_IRQ=Y or CONFIG_TRACE_IRQFLAGS=Y. Otherwise, following warnings happen: CC kernel/irq/handle.o kernel/irq/handle.c:26: warning: 'irq_desc_lock_class' defined but not used Actually, current early_init_irq_lock_class has a bit strange and messy ifdef. In addition, it is not valueable. 1. this function is protected by !CONFIG_SPARSE_IRQ, but that is not necessary. if CONFIG_SPARSE_IRQ=Y, desc of all irq number are initialized by NULL at first - then this function calling is safe. 2. this function protected by CONFIG_TRACE_IRQFLAGS too. but it is not necessary either, because lockdep_set_class() doesn't have bad side effect even if CONFIG_TRACE_IRQFLAGS=n. This patch bloat kernel size a bit on CONFIG_TRACE_IRQFLAGS=n and CONFIG_SPARSE_IRQ=Y - but that's ok. early_init_irq_lock_class() is not a fastpatch at all. To avoid messy ifdefs is more important than a few bytes diet. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * lockdep: include/linux/lockdep.h - fix warning in net/bluetooth/af_bluetooth.cIngo Molnar2008-11-131-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fix this warning: net/bluetooth/af_bluetooth.c:60: warning: ‘bt_key_strings’ defined but not used net/bluetooth/af_bluetooth.c:71: warning: ‘bt_slock_key_strings’ defined but not used this is a lockdep macro problem in the !LOCKDEP case. We cannot convert it to an inline because the macro works on multiple types, but we can mark the parameter used. [ also clean up a misaligned tab in sock_lock_init_class_and_name() ] [ also remove #ifdefs from around af_family_clock_key strings - which were certainly added to get rid of the ugly build warnings. ] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: David S. Miller <davem@davemloft.net>
* | lockdep: change a held lock's classPeter Zijlstra2008-12-041-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | Impact: introduce new lockdep API Allow to change a held lock's class. Basically the same as the existing code to change a subclass therefore reuse all that. The XFS code will be able to use this to annotate their inode locking. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | lockdep: include/linux/lockdep.h - fix warning in net/bluetooth/af_bluetooth.cIngo Molnar2008-11-121-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fix this warning: net/bluetooth/af_bluetooth.c:60: warning: ‘bt_key_strings’ defined but not used net/bluetooth/af_bluetooth.c:71: warning: ‘bt_slock_key_strings’ defined but not used this is a lockdep macro problem in the !LOCKDEP case. We cannot convert it to an inline because the macro works on multiple types, but we can mark the parameter used. [ also clean up a misaligned tab in sock_lock_init_class_and_name() ] [ also remove #ifdefs from around af_family_clock_key strings - which were certainly added to get rid of the ugly build warnings. ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | lockstat: contend with pointsPeter Zijlstra2008-10-201-4/+9
| | | | | | | | | | | | | | | | We currently only provide points that have to wait on contention, also lists the points we have to wait for. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | lockdep: add might_lock() / might_lock_read()Peter Zijlstra2008-09-101-0/+18
|/ | | | | | | | | useful to establish a lock dependency in case the actual dependency is rare or hard to trigger. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: increase MAX_LOCKDEP_KEYSIngo Molnar2008-08-111-1/+1
| | | | | | | | | | | certain configs produce: [ 70.076229] BUG: MAX_LOCKDEP_KEYS too low! [ 70.080230] turning off the locking correctness validator. tune them up. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: fix overflow in the hlock shrinkage codePeter Zijlstra2008-08-111-1/+6
| | | | | | | There is a overflow by 1 case in the new shrunken hlock code. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: rename map_[acquire|release]() => lock_map_[acquire|release]()Ingo Molnar2008-08-111-5/+5
| | | | | | | | | | the names were too generic: drivers/uio/uio.c:87: error: expected identifier or '(' before 'do' drivers/uio/uio.c:87: error: expected identifier or '(' before 'while' drivers/uio/uio.c:113: error: 'map_release' undeclared here (not in a function) Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: spin_lock_nest_lock()Peter Zijlstra2008-08-111-0/+2
| | | | | | | | | | | | | Expose the new lock protection lock. This can be used to annotate places where we take multiple locks of the same class and avoid deadlocks by always taking another (top-level) lock first. NOTE: we're still bound to the MAX_LOCK_DEPTH (48) limit. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: lock protection locksPeter Zijlstra2008-08-111-16/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On Fri, 2008-08-01 at 16:26 -0700, Linus Torvalds wrote: > On Fri, 1 Aug 2008, David Miller wrote: > > > > Taking more than a few locks of the same class at once is bad > > news and it's better to find an alternative method. > > It's not always wrong. > > If you can guarantee that anybody that takes more than one lock of a > particular class will always take a single top-level lock _first_, then > that's all good. You can obviously screw up and take the same lock _twice_ > (which will deadlock), but at least you cannot get into ABBA situations. > > So maybe the right thing to do is to just teach lockdep about "lock > protection locks". That would have solved the multi-queue issues for > networking too - all the actual network drivers would still have taken > just their single queue lock, but the one case that needs to take all of > them would have taken a separate top-level lock first. > > Never mind that the multi-queue locks were always taken in the same order: > it's never wrong to just have some top-level serialization, and anybody > who needs to take <n> locks might as well do <n+1>, because they sure as > hell aren't going to be on _any_ fastpaths. > > So the simplest solution really sounds like just teaching lockdep about > that one special case. It's not "nesting" exactly, although it's obviously > related to it. Do as Linus suggested. The lock protection lock is called nest_lock. Note that we still have the MAX_LOCK_DEPTH (48) limit to consider, so anything that spills that it still up shit creek. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: map_acquirePeter Zijlstra2008-08-111-0/+12
| | | | | | | | Most the free-standing lock_acquire() usages look remarkably similar, sweep them into a new helper. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: shrink held_lock structureDave Jones2008-08-111-7/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | struct held_lock { u64 prev_chain_key; /* 0 8 */ struct lock_class * class; /* 8 8 */ long unsigned int acquire_ip; /* 16 8 */ struct lockdep_map * instance; /* 24 8 */ int irq_context; /* 32 4 */ int trylock; /* 36 4 */ int read; /* 40 4 */ int check; /* 44 4 */ int hardirqs_off; /* 48 4 */ /* size: 56, cachelines: 1 */ /* padding: 4 */ /* last cacheline: 56 bytes */ }; struct held_lock { u64 prev_chain_key; /* 0 8 */ long unsigned int acquire_ip; /* 8 8 */ struct lockdep_map * instance; /* 16 8 */ unsigned int class_idx:11; /* 24:21 4 */ unsigned int irq_context:2; /* 24:19 4 */ unsigned int trylock:1; /* 24:18 4 */ unsigned int read:2; /* 24:16 4 */ unsigned int check:2; /* 24:14 4 */ unsigned int hardirqs_off:1; /* 24:13 4 */ /* size: 32, cachelines: 1 */ /* padding: 4 */ /* bit_padding: 13 bits */ /* last cacheline: 32 bytes */ }; [mingo@elte.hu: shrunk hlock->class too] [peterz@infradead.org: fixup bit sizes] Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
* lockdep: lock_set_subclass - reset a held lock's subclassPeter Zijlstra2008-08-111-0/+4
| | | | | | | | | this can be used to reset a held lock's subclass, for arbitrary-depth iterated data structures such as trees or lists which have per-node locks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: fix combinatorial explosion in lock subgraph traversalDavid Miller2008-07-311-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we traverse the graph, either forwards or backwards, we are interested in whether a certain property exists somewhere in a node reachable in the graph. Therefore it is never necessary to traverse through a node more than once to get a correct answer to the given query. Take advantage of this property using a global ID counter so that we need not clear all the markers in all the lock_class entries before doing a traversal. A new ID is choosen when we start to traverse, and we continue through a lock_class only if it's ID hasn't been marked with the new value yet. This short-circuiting is essential especially for high CPU count systems. The scheduler has a runqueue per cpu, and needs to take two runqueue locks at a time, which leads to long chains of backwards and forwards subgraphs from these runqueue lock nodes. Without the short-circuit implemented here, a graph traversal on a runqueue lock can take up to (1 << (N - 1)) checks on a system with N cpus. For anything more than 16 cpus or so, lockdep will eventually bring the machine to a complete standstill. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: remove duplicate definition of STATIC_LOCKDEP_MAP_INITLi Zefan2008-06-241-8/+0
| | | | | | | | | STATIC_LOCKDEP_MAP_INIT is defined twice in lockdep.h. I guess it's a copy & paste. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: add lock_class information to lock_chain and output itHuang, Ying2008-06-201-0/+3
| | | | | | | | | | | | This patch records array of lock_class into lock_chain, and export lock_chain information via /proc/lockdep_chains. It is based on x86/master branch of git-x86 tree, and has been tested on x86_64 platform. Signed-off-by: Huang Ying <ying.huang@intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* workqueue: debug flushing deadlocks with lockdepJohannes Berg2007-10-191-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | In the following scenario: code path 1: my_function() -> lock(L1); ...; flush_workqueue(); ... code path 2: run_workqueue() -> my_work() -> ...; lock(L1); ... you can get a deadlock when my_work() is queued or running but my_function() has acquired L1 already. This patch adds a pseudo-lock to each workqueue to make lockdep warn about this scenario. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lockdep: annotate rcu_read_{,un}lock{,_bh}Peter Zijlstra2007-10-111-0/+7
| | | | | | | | | lockdep annotate rcu_read_{,un}lock{,_bh} in order to catch imbalanced usage. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* lockdep: syscall exit checkPeter Zijlstra2007-10-111-0/+2
| | | | | | | | Provide a check to validate that we do not hold any locks when switching back to user-space. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockstat: measure lock bouncingPeter Zijlstra2007-07-191-1/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __acquire | lock _____ | \ | __contended | | | wait | _______/ |/ | __acquired | __release | unlock We measure acquisition and contention bouncing. This is done by recording a cpu stamp in each lock instance. Contention bouncing requires the cpu stamp to be set on acquisition. Hence we move __acquired into the generic path. __acquired is then used to measure acquisition bouncing by comparing the current cpu with the old stamp before replacing it. __contended is used to measure contention bouncing (only useful for preemptable locks) [akpm@linux-foundation.org: cleanups] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lockdep: various fixesPeter Zijlstra2007-07-191-1/+2
| | | | | | | | | | | | | | - update the copyright notices - use the default hash function - fix a thinko in a BUILD_BUG_ON - add a WARN_ON to spot inconsitent naming - fix a termination issue in /proc/lock_stat [akpm@linux-foundation.org: cleanups] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lockstat: core infrastructurePeter Zijlstra2007-07-191-0/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce the core lock statistics code. Lock statistics provides lock wait-time and hold-time (as well as the count of corresponding contention and acquisitions events). Also, the first few call-sites that encounter contention are tracked. Lock wait-time is the time spent waiting on the lock. This provides insight into the locking scheme, that is, a heavily contended lock is indicative of a too coarse locking scheme. Lock hold-time is the duration the lock was held, this provides a reference for the wait-time numbers, so they can be put into perspective. 1) lock 2) ... do stuff .. unlock 3) The time between 1 and 2 is the wait-time. The time between 2 and 3 is the hold-time. The lockdep held-lock tracking code is reused, because it already collects locks into meaningful groups (classes), and because it is an existing infrastructure for lock instrumentation. Currently lockdep tracks lock acquisition with two hooks: lock() lock_acquire() _lock() ... code protected by lock ... unlock() lock_release() _unlock() We need to extend this with two more hooks, in order to measure contention. lock_contended() - used to measure contention events lock_acquired() - completion of the contention These are then placed the following way: lock() lock_acquire() if (!_try_lock()) lock_contended() _lock() lock_acquired() ... do locked stuff ... unlock() lock_release() _unlock() (Note: the try_lock() 'trick' is used to avoid instrumenting all platform dependent lock primitive implementations.) It is also possible to toggle the two lockdep features at runtime using: /proc/sys/kernel/prove_locking /proc/sys/kernel/lock_stat (esp. turning off the O(n^2) prove_locking functionaliy can help) [akpm@linux-foundation.org: build fixes] [akpm@linux-foundation.org: nuke unneeded ifdefs] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] lockdep: lockdep_depth vs. debug_locksJarek Poplawski2007-03-221-1/+1
| | | | | | | | | | | | | | | lockdep found a bug during a run of workqueue function - this could be also caused by a bug from other code running simultaneously. lockdep really shouldn't be used when debug_locks == 0! Reported-by: Folkert van Heusden <folkert@vanheusden.com> Inspired-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Jarek Poplawski <jarkao2@o2.pl> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] lockdep: forward declare struct task_structHeiko Carstens2007-02-121-0/+2
| | | | | | | | | | | | | | | | | | 3117df0453828bd045c16244e6f50e5714667a8a causes this: In file included from arch/s390/kernel/early.c:13: include/linux/lockdep.h:300: warning: "struct task_struct" declared inside parameter list include/linux/lockdep.h:300: warning: its scope is only this definition or declaration, which is probably not what you want Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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