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2014-01-20Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds8-74/+251
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: - add RCU torture scripts/tooling - static analysis improvements - update RCU documentation - miscellaneous fixes * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits) rcu: Remove "extern" from function declarations in kernel/rcu/rcu.h rcu: Remove "extern" from function declarations in include/linux/*rcu*.h rcu/torture: Dynamically allocate SRCU output buffer to avoid overflow rcu: Don't activate RCU core on NO_HZ_FULL CPUs rcu: Warn on allegedly impossible rcu_read_unlock_special() from irq rcu: Add an RCU_INITIALIZER for global RCU-protected pointers rcu: Make rcu_assign_pointer's assignment volatile and type-safe bonding: Use RCU_INIT_POINTER() for better overhead and for sparse rcu: Add comment on evaluate-once properties of rcu_assign_pointer(). rcu: Provide better diagnostics for blocking in RCU callback functions rcu: Improve SRCU's grace-period comments rcu: Fix CONFIG_RCU_FANOUT_EXACT for odd fanout/leaf values rcu: Fix coccinelle warnings rcutorture: Stop tracking FSF's postal address rcutorture: Move checkarg to functions.sh rcutorture: Flag errors and warnings with color coding rcutorture: Record results from repeated runs of the same test scenario rcutorture: Test summary at end of run with less chattiness rcutorture: Update comment in kvm.sh listing typical RCU trace events rcutorture: Add tracing-enabled version of TREE08 ...
2014-01-20Merge branch 'core-locking-for-linus' of ↵Linus Torvalds6-50/+242
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core locking changes from Ingo Molnar: - futex performance increases: larger hashes, smarter wakeups - mutex debugging improvements - lots of SMP ordering documentation updates - introduce the smp_load_acquire(), smp_store_release() primitives. (There are WIP patches that make use of them - not yet merged) - lockdep micro-optimizations - lockdep improvement: better cover IRQ contexts - liblockdep at last. We'll continue to monitor how useful this is * 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits) futexes: Fix futex_hashsize initialization arch: Re-sort some Kbuild files to hopefully help avoid some conflicts futexes: Avoid taking the hb->lock if there's nothing to wake up futexes: Document multiprocessor ordering guarantees futexes: Increase hash table size for better performance futexes: Clean up various details arch: Introduce smp_load_acquire(), smp_store_release() arch: Clean up asm/barrier.h implementations using asm-generic/barrier.h arch: Move smp_mb__{before,after}_atomic_{inc,dec}.h into asm/atomic.h locking/doc: Rename LOCK/UNLOCK to ACQUIRE/RELEASE mutexes: Give more informative mutex warning in the !lock->owner case powerpc: Full barrier for smp_mb__after_unlock_lock() rcu: Apply smp_mb__after_unlock_lock() to preserve grace periods Documentation/memory-barriers.txt: Downgrade UNLOCK+BLOCK locking: Add an smp_mb__after_unlock_lock() for UNLOCK+BLOCK barrier Documentation/memory-barriers.txt: Document ACCESS_ONCE() Documentation/memory-barriers.txt: Prohibit speculative writes Documentation/memory-barriers.txt: Add long atomic examples to memory-barriers.txt Documentation/memory-barriers.txt: Add needed ACCESS_ONCE() calls to memory-barriers.txt Revert "smp/cpumask: Make CONFIG_CPUMASK_OFFSTACK=y usable without debug dependency" ...
2014-01-20Merge branch 'core-debug-for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core debug changes from Ingo Molnar: "Currently there are two methods to set the panic_timeout: via 'panic=X' boot commandline option, or via /proc/sys/kernel/panic. This tree adds a third panic_timeout configuration method: configuration via Kconfig, via CONFIG_PANIC_TIMEOUT=X - useful to distros that generally want their kernel defaults to come with the .config. CONFIG_PANIC_TIMEOUT defaults to 0, which was the previous default value of panic_timeout. Doing that unearthed a few arch trickeries regarding arch-special panic_timeout values and related complications - hopefully all resolved to the satisfaction of everyone" * 'core-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: powerpc: Clean up panic_timeout usage MIPS: Remove panic_timeout settings panic: Make panic_timeout configurable
2014-01-17Merge branch 'for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull namespace fixes from Eric Biederman: "This is a set of 3 regression fixes. This fixes /proc/mounts when using "ip netns add <netns>" to display the actual mount point. This fixes a regression in clone that broke lxc-attach. This fixes a regression in the permission checks for mounting /proc that made proc unmountable if binfmt_misc was in use. Oops. My apologies for sending this pull request so late. Al Viro gave interesting review comments about the d_path fix that I wanted to address in detail before I sent this pull request. Unfortunately a bad round of colds kept from addressing that in detail until today. The executive summary of the review was: Al: Is patching d_path really sufficient? The prepend_path, d_path, d_absolute_path, and __d_path family of functions is a really mess. Me: Yes, patching d_path is really sufficient. Yes, the code is mess. No it is not appropriate to rewrite all of d_path for a regression that has existed for entirely too long already, when a two line change will do" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: vfs: Fix a regression in mounting proc fork: Allow CLONE_PARENT after setns(CLONE_NEWPID) vfs: In d_path don't call d_dname on a mount point
2014-01-16futexes: Fix futex_hashsize initializationHeiko Carstens1-2/+4
"futexes: Increase hash table size for better performance" introduces a new alloc_large_system_hash() call. alloc_large_system_hash() however may allocate less memory than requested, e.g. limited by MAX_ORDER. Hence pass a pointer to alloc_large_system_hash() which will contain the hash shift when the function returns. Afterwards correctly set futex_hashsize. Fixes a crash on s390 where the requested allocation size was 4MB but only 1MB was allocated. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Darren Hart <dvhart@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Waiman Long <Waiman.Long@hp.com> Cc: Jason Low <jason.low2@hp.com> Cc: Davidlohr Bueso <davidlohr@hp.com> Link: http://lkml.kernel.org/r/20140116135450.GA4345@osiris Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-16Merge branches 'sched-urgent-for-linus' and 'timers-urgent-for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler and timer fixes from Ingo Molnar: "Contains a fix for a scheduler bug that manifested itself as a 3D performance regression and a crash fix for the ARM Cadence TTC clock driver" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Calculate effective load even if local weight is 0 * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource: cadence_ttc: Fix mutex taken inside interrupt context
2014-01-13futexes: Avoid taking the hb->lock if there's nothing to wake upDavidlohr Bueso1-25/+92
In futex_wake() there is clearly no point in taking the hb->lock if we know beforehand that there are no tasks to be woken. While the hash bucket's plist head is a cheap way of knowing this, we cannot rely 100% on it as there is a racy window between the futex_wait call and when the task is actually added to the plist. To this end, we couple it with the spinlock check as tasks trying to enter the critical region are most likely potential waiters that will be added to the plist, thus preventing tasks sleeping forever if wakers don't acknowledge all possible waiters. Furthermore, the futex ordering guarantees are preserved, ensuring that waiters either observe the changed user space value before blocking or is woken by a concurrent waker. For wakers, this is done by relying on the barriers in get_futex_key_refs() -- for archs that do not have implicit mb in atomic_inc(), we explicitly add them through a new futex_get_mm function. For waiters we rely on the fact that spin_lock calls already update the head counter, so spinners are visible even if the lock hasn't been acquired yet. For more details please refer to the updated comments in the code and related discussion: https://lkml.org/lkml/2013/11/26/556 Special thanks to tglx for careful review and feedback. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Darren Hart <dvhart@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Scott Norton <scott.norton@hp.com> Cc: Tom Vaden <tom.vaden@hp.com> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: Waiman Long <Waiman.Long@hp.com> Cc: Jason Low <jason.low2@hp.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1389569486-25487-5-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-13futexes: Document multiprocessor ordering guaranteesThomas Gleixner1-0/+57
That's essential, if you want to hack on futexes. Reviewed-by: Darren Hart <dvhart@linux.intel.com> Reviewed-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Scott Norton <scott.norton@hp.com> Cc: Tom Vaden <tom.vaden@hp.com> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: Waiman Long <Waiman.Long@hp.com> Cc: Jason Low <jason.low2@hp.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1389569486-25487-4-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-13futexes: Increase hash table size for better performanceDavidlohr Bueso1-7/+19
Currently, the futex global hash table suffers from its fixed, smallish (for today's standards) size of 256 entries, as well as its lack of NUMA awareness. Large systems, using many futexes, can be prone to high amounts of collisions; where these futexes hash to the same bucket and lead to extra contention on the same hb->lock. Furthermore, cacheline bouncing is a reality when we have multiple hb->locks residing on the same cacheline and different futexes hash to adjacent buckets. This patch keeps the current static size of 16 entries for small systems, or otherwise, 256 * ncpus (or larger as we need to round the number to a power of 2). Note that this number of CPUs accounts for all CPUs that can ever be available in the system, taking into consideration things like hotpluging. While we do impose extra overhead at bootup by making the hash table larger, this is a one time thing, and does not shadow the benefits of this patch. Furthermore, as suggested by tglx, by cache aligning the hash buckets we can avoid access across cacheline boundaries and also avoid massive cache line bouncing if multiple cpus are hammering away at different hash buckets which happen to reside in the same cache line. Also, similar to other core kernel components (pid, dcache, tcp), by using alloc_large_system_hash() we benefit from its NUMA awareness and thus the table is distributed among the nodes instead of in a single one. For a custom microbenchmark that pounds on the uaddr hashing -- making the wait path fail at futex_wait_setup() returning -EWOULDBLOCK for large amounts of futexes, we can see the following benefits on a 80-core, 8-socket 1Tb server: +---------+--------------------+------------------------+-----------------------+-------------------------------+ | threads | baseline (ops/sec) | aligned-only (ops/sec) | large table (ops/sec) | large table+aligned (ops/sec) | +---------+--------------------+------------------------+-----------------------+-------------------------------+ |     512 |              32426 | 50531  (+55.8%)        | 255274  (+687.2%)     | 292553  (+802.2%)             | |     256 |              65360 | 99588  (+52.3%)        | 443563  (+578.6%)     | 508088  (+677.3%)             | |     128 |             125635 | 200075 (+59.2%)        | 742613  (+491.1%)     | 835452  (+564.9%)             | |      80 |             193559 | 323425 (+67.1%)        | 1028147 (+431.1%)     | 1130304 (+483.9%)             | |      64 |             247667 | 443740 (+79.1%)        | 997300  (+302.6%)     | 1145494 (+362.5%)             | |      32 |             628412 | 721401 (+14.7%)        | 965996  (+53.7%)      | 1122115 (+78.5%)              | +---------+--------------------+------------------------+-----------------------+-------------------------------+ Reviewed-by: Darren Hart <dvhart@linux.intel.com> Reviewed-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Waiman Long <Waiman.Long@hp.com> Reviewed-and-tested-by: Jason Low <jason.low2@hp.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Scott Norton <scott.norton@hp.com> Cc: Tom Vaden <tom.vaden@hp.com> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Link: http://lkml.kernel.org/r/1389569486-25487-3-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-13futexes: Clean up various detailsJason Low1-27/+12
- Remove unnecessary head variables. - Delete unused parameter in queue_unlock(). Reviewed-by: Darren Hart <dvhart@linux.intel.com> Reviewed-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jason Low <jason.low2@hp.com> Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Jeff Mahoney <jeffm@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Scott Norton <scott.norton@hp.com> Cc: Tom Vaden <tom.vaden@hp.com> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: Waiman Long <Waiman.Long@hp.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1389569486-25487-2-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-13Merge tag 'v3.13-rc8' into core/lockingIngo Molnar14-112/+158
Refresh the tree with the latest fixes, before applying new changes. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-12sched_clock: Disable seqlock lockdep usage in sched_clock()John Stultz1-3/+3
Unfortunately the seqlock lockdep enablement can't be used in sched_clock(), since the lockdep infrastructure eventually calls into sched_clock(), which causes a deadlock. Thus, this patch changes all generic sched_clock() usage to use the raw_* methods. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Reported-by: Krzysztof Hałasa <khalasa@piap.pl> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1388704274-5278-2-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-12sched: Calculate effective load even if local weight is 0Rik van Riel1-1/+1
Thomas Hellstrom bisected a regression where erratic 3D performance is experienced on virtual machines as measured by glxgears. It identified commit 58d081b5 ("sched/numa: Avoid overloading CPUs on a preferred NUMA node") as the problem which had modified the behaviour of effective_load. Effective load calculates the difference to the system-wide load if a scheduling entity was moved to another CPU. The task group is not heavier as a result of the move but overall system load can increase/decrease as a result of the change. Commit 58d081b5 ("sched/numa: Avoid overloading CPUs on a preferred NUMA node") changed effective_load to make it suitable for calculating if a particular NUMA node was compute overloaded. To reduce the cost of the function, it assumed that a current sched entity weight of 0 was uninteresting but that is not the case. wake_affine() uses a weight of 0 for sync wakeups on the grounds that it is assuming the waking task will sleep and not contribute to load in the near future. In this case, we still want to calculate the effective load of the sched entity hierarchy. As effective_load is no longer used by task_numa_compare since commit fb13c7ee (sched/numa: Use a system-wide search to find swap/migration candidates), this patch simply restores the historical behaviour. Reported-and-tested-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Rik van Riel <riel@redhat.com> [ Wrote changelog] Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140106113912.GC6178@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-29Merge tag 'pm+acpi-3.13-rc6' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull ACPI and power management fixes and new device IDs from Rafael Wysocki: - Fix for a cpufreq regression causing stale sysfs files to be left behind during system resume if cpufreq_add_dev() fails for one or more CPUs from Viresh Kumar. - Fix for a bug in cpufreq causing CONFIG_CPU_FREQ_DEFAULT_* to be ignored when the intel_pstate driver is used from Jason Baron. - System suspend fix for a memory leak in pm_vt_switch_unregister() that forgot to release objects after removing them from pm_vt_switch_list. From Masami Ichikawa. - Intel Valley View device ID and energy unit encoding update for the (recently added) Intel RAPL (Running Average Power Limit) driver from Jacob Pan. - Intel Bay Trail SoC GPIO and ACPI device IDs for the Low Power Subsystem (LPSS) ACPI driver from Paul Drews. * tag 'pm+acpi-3.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: powercap / RAPL: add support for ValleyView Soc PM / sleep: Fix memory leak in pm_vt_switch_unregister(). cpufreq: Use CONFIG_CPU_FREQ_DEFAULT_* to set initial policy for setpolicy drivers cpufreq: remove sysfs files for CPUs which failed to come back after resume ACPI: Add BayTrail SoC GPIO and LPSS ACPI IDs
2013-12-27Merge branches 'pm-cpufreq' and 'pm-sleep' containing PM fixesRafael J. Wysocki1-0/+1
* pm-cpufreq: cpufreq: Use CONFIG_CPU_FREQ_DEFAULT_* to set initial policy for setpolicy drivers cpufreq: remove sysfs files for CPUs which failed to come back after resume * pm-sleep: PM / sleep: Fix memory leak in pm_vt_switch_unregister().
2013-12-24Merge branch 'for-3.13-fixes' of ↵Linus Torvalds1-18/+32
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: "Two fixes. One fixes a bug in the error path of cgroup_create(). The other changes cgrp->id lifetime rule so that the id doesn't get recycled before all controller states are destroyed. This premature id recycling made memcg malfunction" * 'for-3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: don't recycle cgroup id until all csses' have been destroyed cgroup: fix cgroup_create() error handling path
2013-12-24Merge branch 'for-3.13-fixes' of ↵Linus Torvalds1-0/+6
git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata Pull libata fixes from Tejun Heo: "There's one interseting commit - "libata, freezer: avoid block device removal while system is frozen". It's an ugly hack working around a deadlock condition between driver core resume and block layer device removal paths through freezer which was made more reproducible by writeback being converted to workqueue some releases ago. The bug has nothing to do with libata but it's just an workaround which is easy to backport. After discussion, Rafael and I seem to agree that we don't really need kernel freezables - both kthread and workqueue. There are few specific workqueues which constitute PM operations and require freezing, which will be converted to use workqueue_set_max_active() instead. All other kernel freezer uses are planned to be removed, followed by the removal of kthread and workqueue freezer support, hopefully. Others are device-specific fixes. The most notable is the addition of NO_NCQ_TRIM which is used to disable queued TRIM commands to Micro M500 SSDs which otherwise suffers data corruption" * 'for-3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata: libata, freezer: avoid block device removal while system is frozen libata: implement ATA_HORKAGE_NO_NCQ_TRIM and apply it to Micro M500 SSDs libata: disable a disk via libata.force params ahci: bail out on ICH6 before using AHCI BAR ahci: imx: Explicitly clear IMX6Q_GPR13_SATA_MPLL_CLK_EN libata: add ATA_HORKAGE_BROKEN_FPDMA_AA quirk for Seagate Momentus SpinPoint M8
2013-12-22PM / sleep: Fix memory leak in pm_vt_switch_unregister().Masami Ichikawa1-0/+1
kmemleak reported a memory leak as below. unreferenced object 0xffff880118f14700 (size 32): comm "swapper/0", pid 1, jiffies 4294877401 (age 123.283s) hex dump (first 32 bytes): 00 01 10 00 00 00 ad de 00 02 20 00 00 00 ad de .......... ..... 00 d4 d2 18 01 88 ff ff 01 00 00 00 00 04 00 00 ................ backtrace: [<ffffffff814edb1e>] kmemleak_alloc+0x4e/0xb0 [<ffffffff811889dc>] kmem_cache_alloc_trace+0x1ec/0x260 [<ffffffff810aba66>] pm_vt_switch_required+0x76/0xb0 [<ffffffff812f39f5>] register_framebuffer+0x195/0x320 [<ffffffff8130af18>] efifb_probe+0x718/0x780 [<ffffffff81391495>] platform_drv_probe+0x45/0xb0 [<ffffffff8138f407>] driver_probe_device+0x87/0x3a0 [<ffffffff8138f7f3>] __driver_attach+0x93/0xa0 [<ffffffff8138d413>] bus_for_each_dev+0x63/0xa0 [<ffffffff8138ee5e>] driver_attach+0x1e/0x20 [<ffffffff8138ea40>] bus_add_driver+0x180/0x250 [<ffffffff8138fe74>] driver_register+0x64/0xf0 [<ffffffff813913ba>] __platform_driver_register+0x4a/0x50 [<ffffffff8191e028>] efifb_driver_init+0x12/0x14 [<ffffffff8100214a>] do_one_initcall+0xfa/0x1b0 [<ffffffff818e40e0>] kernel_init_freeable+0x17b/0x201 In pm_vt_switch_required(), "entry" variable is allocated via kmalloc(). So, in pm_vt_switch_unregister(), it needs to call kfree() when object is deleted from list. Signed-off-by: Masami Ichikawa <masami256@gmail.com> Reviewed-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-12-20mm: do not allocate page->ptl dynamically, if spinlock_t fits to longKirill A. Shutemov1-1/+1
In struct page we have enough space to fit long-size page->ptl there, but we use dynamically-allocated page->ptl if size(spinlock_t) is larger than sizeof(int). It hurts 64-bit architectures with CONFIG_GENERIC_LOCKBREAK, where sizeof(spinlock_t) == 8, but it easily fits into struct page. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-20Merge tag 'trace-fixes-v3.13-rc2' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull ftrace fix from Steven Rostedt: "This fixes a long standing bug in the ftrace profiler. The problem is that the profiler only initializes the online CPUs, and not possible CPUs. This causes issues if the user takes CPUs online or offline while the profiler is running. If we online a CPU after starting the profiler, we lose all the trace information on the CPU going online. If we offline a CPU after running a test and start a new test, it will not clear the old data from that CPU. This bug causes incorrect data to be reported to the user if they online or offline CPUs during the profiling" * tag 'trace-fixes-v3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace: Initialize the ftrace profiler for each possible cpu
2013-12-19libata, freezer: avoid block device removal while system is frozenTejun Heo1-0/+6
Freezable kthreads and workqueues are fundamentally problematic in that they effectively introduce a big kernel lock widely used in the kernel and have already been the culprit of several deadlock scenarios. This is the latest occurrence. During resume, libata rescans all the ports and revalidates all pre-existing devices. If it determines that a device has gone missing, the device is removed from the system which involves invalidating block device and flushing bdi while holding driver core layer locks. Unfortunately, this can race with the rest of device resume. Because freezable kthreads and workqueues are thawed after device resume is complete and block device removal depends on freezable workqueues and kthreads (e.g. bdi_wq, jbd2) to make progress, this can lead to deadlock - block device removal can't proceed because kthreads are frozen and kthreads can't be thawed because device resume is blocked behind block device removal. 839a8e8660b6 ("writeback: replace custom worker pool implementation with unbound workqueue") made this particular deadlock scenario more visible but the underlying problem has always been there - the original forker task and jbd2 are freezable too. In fact, this is highly likely just one of many possible deadlock scenarios given that freezer behaves as a big kernel lock and we don't have any debug mechanism around it. I believe the right thing to do is getting rid of freezable kthreads and workqueues. This is something fundamentally broken. For now, implement a funny workaround in libata - just avoid doing block device hot[un]plug while the system is frozen. Kernel engineering at its finest. :( v2: Add EXPORT_SYMBOL_GPL(pm_freezing) for cases where libata is built as a module. v3: Comment updated and polling interval changed to 10ms as suggested by Rafael. v4: Add #ifdef CONFIG_FREEZER around the hack as pm_freezing is not defined when FREEZER is not configured thus breaking build. Reported by kbuild test robot. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Tomaž Šolc <tomaz.solc@tablix.org> Reviewed-by: "Rafael J. Wysocki" <rjw@rjwysocki.net> Link: https://bugzilla.kernel.org/show_bug.cgi?id=62801 Link: http://lkml.kernel.org/r/20131213174932.GA27070@htj.dyndns.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Len Brown <len.brown@intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: stable@vger.kernel.org Cc: kbuild test robot <fengguang.wu@intel.com>
2013-12-19Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2-2/+17
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "An RT group-scheduling fix and the sched-domains topology setup fix from Mel" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/rt: Fix rq's cpupri leak while enqueue/dequeue child RT entities sched: Assign correct scheduling domain to 'sd_llc'
2013-12-19Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds1-3/+18
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "An ABI documentation fix, and a mixed-PMU perf-info-corruption fix" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Document the new transaction sample type perf: Disable all pmus on unthrottling and rescheduling
2013-12-18Merge branch 'akpm' (incoming from Andrew)Linus Torvalds4-1/+10
Merge patches from Andrew Morton: "23 fixes and a MAINTAINERS update" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (24 commits) mm/hugetlb: check for pte NULL pointer in __page_check_address() fix build with make 3.80 mm/mempolicy: fix !vma in new_vma_page() MAINTAINERS: add Davidlohr as GPT maintainer mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully mm/compaction: respect ignore_skip_hint in update_pageblock_skip mm/mempolicy: correct putback method for isolate pages if failed mm: add missing dependency in Kconfig sh: always link in helper functions extracted from libgcc mm: page_alloc: exclude unreclaimable allocations from zone fairness policy mm: numa: defer TLB flush for THP migration as long as possible mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates mm: fix TLB flush race between migration, and change_protection_range mm: numa: avoid unnecessary disruption of NUMA hinting during migration mm: numa: clear numa hinting information on mprotect sched: numa: skip inaccessible VMAs mm: numa: avoid unnecessary work on the failure path mm: numa: ensure anon_vma is locked to prevent parallel THP splits mm: numa: do not clear PTE for pte_numa update mm: numa: do not clear PMD during PTE update scan ...
2013-12-18mm: fix TLB flush race between migration, and change_protection_rangeRik van Riel1-0/+1
There are a few subtle races, between change_protection_range (used by mprotect and change_prot_numa) on one side, and NUMA page migration and compaction on the other side. The basic race is that there is a time window between when the PTE gets made non-present (PROT_NONE or NUMA), and the TLB is flushed. During that time, a CPU may continue writing to the page. This is fine most of the time, however compaction or the NUMA migration code may come in, and migrate the page away. When that happens, the CPU may continue writing, through the cached translation, to what is no longer the current memory location of the process. This only affects x86, which has a somewhat optimistic pte_accessible. All other architectures appear to be safe, and will either always flush, or flush whenever there is a valid mapping, even with no permissions (SPARC). The basic race looks like this: CPU A CPU B CPU C load TLB entry make entry PTE/PMD_NUMA fault on entry read/write old page start migrating page change PTE/PMD to new page read/write old page [*] flush TLB reload TLB from new entry read/write new page lose data [*] the old page may belong to a new user at this point! The obvious fix is to flush remote TLB entries, by making sure that pte_accessible aware of the fact that PROT_NONE and PROT_NUMA memory may still be accessible if there is a TLB flush pending for the mm. This should fix both NUMA migration and compaction. [mgorman@suse.de: fix build] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-18sched: numa: skip inaccessible VMAsMel Gorman1-0/+7
Inaccessible VMA should not be trapping NUMA hint faults. Skip them. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-18kexec: migrate to reboot cpuVivek Goyal2-1/+2
Commit 1b3a5d02ee07 ("reboot: move arch/x86 reboot= handling to generic kernel") moved reboot= handling to generic code. In the process it also removed the code in native_machine_shutdown() which are moving reboot process to reboot_cpu/cpu0. I guess that thought must have been that all reboot paths are calling migrate_to_reboot_cpu(), so we don't need this special handling. But kexec reboot path (kernel_kexec()) is not calling migrate_to_reboot_cpu() so above change broke kexec. Now reboot can happen on non-boot cpu and when INIT is sent in second kerneo to bring up BP, it brings down the machine. So start calling migrate_to_reboot_cpu() in kexec reboot path to avoid this problem. Bisected by WANG Chao. Reported-by: Matthew Whitehead <mwhitehe@redhat.com> Reported-by: Dave Young <dyoung@redhat.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Tested-by: Baoquan He <bhe@redhat.com> Tested-by: WANG Chao <chaowang@redhat.com> Acked-by: H. Peter Anvin <hpa@linux.intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-18Merge branch 'keys-devel' of ↵Linus Torvalds2-6/+7
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull crypto key patches from David Howells: "There are four items: - A patch to fix X.509 certificate gathering. The problem was that I was coming up with a different path for signing_key.x509 in the build directory if it didn't exist to if it did exist. This meant that the X.509 cert container object file would be rebuilt on the second rebuild in a build directory and the kernel would get relinked. - Unconditionally remove files generated by SYSTEM_TRUSTED_KEYRING=y when doing make mrproper. - Actually initialise the persistent-keyring semaphore for init_user_ns. I have no idea why this works at all for users in the base user namespace unless it's something to do with systemd containerising the system. - Documentation for module signing" * 'keys-devel' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: Add Documentation/module-signing.txt file KEYS: fix uninitialized persistent_keyring_register_sem KEYS: Remove files generated when SYSTEM_TRUSTED_KEYRING=y X.509: Fix certificate gathering
2013-12-17Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2-80/+65
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "Three fixes for scheduler crashes, each triggers in relatively rare, hardware environment dependent situations" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Rework sched_fair time accounting math64: Add mul_u64_u32_shr() sched: Remove PREEMPT_NEED_RESCHED from generic code sched: Initialize power_orig for overlapping groups
2013-12-17mutexes: Give more informative mutex warning in the !lock->owner caseChuansheng Liu1-1/+6
When mutex debugging is enabled and an imbalanced mutex_unlock() is called, we get the following, slightly confusing warning: [ 364.208284] DEBUG_LOCKS_WARN_ON(lock->owner != current) But in that case the warning is due to an imbalanced mutex_unlock() call, and the lock->owner is NULL - so the message is misleading. So improve the message by testing for this case specifically: DEBUG_LOCKS_WARN_ON(!lock->owner) Signed-off-by: Liu, Chuansheng <chuansheng.liu@intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1386136693.3650.48.camel@cliu38-desktop-build [ Improved the changelog, changed the patch to use !lock->owner consistently. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-17Merge tag 'v3.13-rc4' into core/lockingIngo Molnar36-346/+602
Merge Linux 3.13-rc4, to refresh this rather old tree with the latest fixes. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-17sched/rt: Fix rq's cpupri leak while enqueue/dequeue child RT entitiesKirill Tkhai1-0/+14
This patch touches the RT group scheduling case. Functions inc_rt_prio_smp() and dec_rt_prio_smp() change (global) rq's priority, while rt_rq passed to them may be not the top-level rt_rq. This is wrong, because changing of priority on a child level does not guarantee that the priority is the highest all over the rq. So, this leak makes RT balancing unusable. The short example: the task having the highest priority among all rq's RT tasks (no one other task has the same priority) are waking on a throttle rt_rq. The rq's cpupri is set to the task's priority equivalent, but real rq->rt.highest_prio.curr is less. The patch below fixes the problem. Signed-off-by: Kirill Tkhai <tkhai@yandex.ru> Signed-off-by: Peter Zijlstra <peterz@infradead.org> CC: Steven Rostedt <rostedt@goodmis.org> CC: stable@vger.kernel.org Link: http://lkml.kernel.org/r/49231385567953@web4m.yandex.ru Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-17sched: Assign correct scheduling domain to 'sd_llc'Mel Gorman1-2/+3
Commit 42eb088e (sched: Avoid NULL dereference on sd_busy) corrected a NULL dereference on sd_busy but the fix also altered what scheduling domain it used for the 'sd_llc' percpu variable. One impact of this is that a task selecting a runqueue may consider idle CPUs that are not cache siblings as candidates for running. Tasks are then running on CPUs that are not cache hot. This was found through bisection where ebizzy threads were not seeing equal performance and it looked like a scheduling fairness issue. This patch mitigates but does not completely fix the problem on all machines tested implying there may be an additional bug or a common root cause. Here are the average range of performance seen by individual ebizzy threads. It was tested on top of candidate patches related to x86 TLB range flushing. 4-core machine 3.13.0-rc3 3.13.0-rc3 vanilla fixsd-v3r3 Mean 1 0.00 ( 0.00%) 0.00 ( 0.00%) Mean 2 0.34 ( 0.00%) 0.10 ( 70.59%) Mean 3 1.29 ( 0.00%) 0.93 ( 27.91%) Mean 4 7.08 ( 0.00%) 0.77 ( 89.12%) Mean 5 193.54 ( 0.00%) 2.14 ( 98.89%) Mean 6 151.12 ( 0.00%) 2.06 ( 98.64%) Mean 7 115.38 ( 0.00%) 2.04 ( 98.23%) Mean 8 108.65 ( 0.00%) 1.92 ( 98.23%) 8-core machine Mean 1 0.00 ( 0.00%) 0.00 ( 0.00%) Mean 2 0.40 ( 0.00%) 0.21 ( 47.50%) Mean 3 23.73 ( 0.00%) 0.89 ( 96.25%) Mean 4 12.79 ( 0.00%) 1.04 ( 91.87%) Mean 5 13.08 ( 0.00%) 2.42 ( 81.50%) Mean 6 23.21 ( 0.00%) 69.46 (-199.27%) Mean 7 15.85 ( 0.00%) 101.72 (-541.77%) Mean 8 109.37 ( 0.00%) 19.13 ( 82.51%) Mean 12 124.84 ( 0.00%) 28.62 ( 77.07%) Mean 16 113.50 ( 0.00%) 24.16 ( 78.71%) It's eliminated for one machine and reduced for another. Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Alex Shi <alex.shi@linaro.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: H Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20131217092124.GV11295@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-17perf: Disable all pmus on unthrottling and reschedulingAlexander Shishkin1-3/+18
Currently, only one PMU in a context gets disabled during unthrottling and event_sched_{out,in}(), however, events in one context may belong to different pmus, which results in PMUs being reprogrammed while they are still enabled. This means that mixed PMU use [which is rare in itself] resulted in potentially completely unreliable results: corrupted events, bogus results, etc. This patch temporarily disables PMUs that correspond to each event in the context while these events are being modified. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Link: http://lkml.kernel.org/r/1387196256-8030-1-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-17cgroup: don't recycle cgroup id until all csses' have been destroyedLi Zefan1-8/+11
Hugh reported this bug: > CONFIG_MEMCG_SWAP is broken in 3.13-rc. Try something like this: > > mkdir -p /tmp/tmpfs /tmp/memcg > mount -t tmpfs -o size=1G tmpfs /tmp/tmpfs > mount -t cgroup -o memory memcg /tmp/memcg > mkdir /tmp/memcg/old > echo 512M >/tmp/memcg/old/memory.limit_in_bytes > echo $$ >/tmp/memcg/old/tasks > cp /dev/zero /tmp/tmpfs/zero 2>/dev/null > echo $$ >/tmp/memcg/tasks > rmdir /tmp/memcg/old > sleep 1 # let rmdir work complete > mkdir /tmp/memcg/new > umount /tmp/tmpfs > dmesg | grep WARNING > rmdir /tmp/memcg/new > umount /tmp/memcg > > Shows lots of WARNING: CPU: 1 PID: 1006 at kernel/res_counter.c:91 > res_counter_uncharge_locked+0x1f/0x2f() > > Breakage comes from 34c00c319ce7 ("memcg: convert to use cgroup id"). > > The lifetime of a cgroup id is different from the lifetime of the > css id it replaced: memsw's css_get()s do nothing to hold on to the > old cgroup id, it soon gets recycled to a new cgroup, which then > mysteriously inherits the old's swap, without any charge for it. Instead of removing cgroup id right after all the csses have been offlined, we should do that after csses have been destroyed. To make sure an invalid css pointer won't be returned after the css is destroyed, make sure css_from_id() returns NULL in this case. tj: Updated comment to note planned changes for cgrp->id. Reported-by: Hugh Dickins <hughd@google.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Tejun Heo <tj@kernel.org>
2013-12-16ftrace: Initialize the ftrace profiler for each possible cpuMiao Xie1-1/+1
Ftrace currently initializes only the online CPUs. This implementation has two problems: - If we online a CPU after we enable the function profile, and then run the test, we will lose the trace information on that CPU. Steps to reproduce: # echo 0 > /sys/devices/system/cpu/cpu1/online # cd <debugfs>/tracing/ # echo <some function name> >> set_ftrace_filter # echo 1 > function_profile_enabled # echo 1 > /sys/devices/system/cpu/cpu1/online # run test - If we offline a CPU before we enable the function profile, we will not clear the trace information when we enable the function profile. It will trouble the users. Steps to reproduce: # cd <debugfs>/tracing/ # echo <some function name> >> set_ftrace_filter # echo 1 > function_profile_enabled # run test # cat trace_stat/function* # echo 0 > /sys/devices/system/cpu/cpu1/online # echo 0 > function_profile_enabled # echo 1 > function_profile_enabled # cat trace_stat/function* # run test # cat trace_stat/function* So it is better that we initialize the ftrace profiler for each possible cpu every time we enable the function profile instead of just the online ones. Link: http://lkml.kernel.org/r/1387178401-10619-1-git-send-email-miaox@cn.fujitsu.com Cc: stable@vger.kernel.org # 2.6.31+ Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-12-16Merge branch 'rcu/next' of ↵Ingo Molnar8-74/+251
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull v3.14 RCU updates from Paul E. McKenney. The main changes: * Update RCU documentation. * Miscellaneous fixes. * Add RCU torture scripts. * Static-analysis improvements. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-16rcu: Apply smp_mb__after_unlock_lock() to preserve grace periodsPaul E. McKenney2-1/+30
RCU must ensure that there is the equivalent of a full memory barrier between any memory access preceding grace period and any memory access following that same grace period, regardless of which CPU(s) happen to execute the two memory accesses. Therefore, downgrading UNLOCK+LOCK to no longer imply a full memory barrier requires some adjustments to RCU. This commit therefore adds smp_mb__after_unlock_lock() invocations as needed after the RCU lock acquisitions that need to be part of a full-memory-barrier UNLOCK+LOCK. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <linux-arch@vger.kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1386799151-2219-7-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-15Merge tag 'pci-v3.13-fixes-2' of ↵Linus Torvalds2-22/+14
git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci Pull PCI updates from Bjorn Helgaas: "PCI device hotplug - Move device_del() from pci_stop_dev() to pci_destroy_dev() (Rafael Wysocki) Host bridge drivers - Update maintainers for DesignWare, i.MX6, Armada, R-Car (Bjorn Helgaas) - mvebu: Return 'unsupported' for Interrupt Line and Interrupt Pin (Jason Gunthorpe) Miscellaneous - Avoid unnecessary CPU switch when calling .probe() (Alexander Duyck) - Revert "workqueue: allow work_on_cpu() to be called recursively" (Bjorn Helgaas) - Disable Bus Master only on kexec reboot (Khalid Aziz) - Omit PCI ID macro strings to shorten quirk names for LTO (Michal Marek)" * tag 'pci-v3.13-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: MAINTAINERS: Add DesignWare, i.MX6, Armada, R-Car PCI host maintainers PCI: Disable Bus Master only on kexec reboot PCI: mvebu: Return 'unsupported' for Interrupt Line and Interrupt Pin PCI: Omit PCI ID macro strings to shorten quirk names PCI: Move device_del() from pci_stop_dev() to pci_destroy_dev() Revert "workqueue: allow work_on_cpu() to be called recursively" PCI: Avoid unnecessary CPU switch when calling driver .probe() method
2013-12-13KEYS: fix uninitialized persistent_keyring_register_semXiao Guangrong1-3/+3
We run into this bug: [ 2736.063245] Unable to handle kernel paging request for data at address 0x00000000 [ 2736.063293] Faulting instruction address: 0xc00000000037efb0 [ 2736.063300] Oops: Kernel access of bad area, sig: 11 [#1] [ 2736.063303] SMP NR_CPUS=2048 NUMA pSeries [ 2736.063310] Modules linked in: sg nfsv3 rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6table_mangle ip6table_security ip6table_raw ip6t_REJECT iptable_nat nf_nat_ipv4 iptable_mangle iptable_security iptable_raw ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack ebtable_filter ebtables ip6table_filter iptable_filter ip_tables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 nf_nat nf_conntrack ip6_tables ibmveth pseries_rng nx_crypto nfsd auth_rpcgss nfs_acl lockd sunrpc binfmt_misc xfs libcrc32c dm_service_time sd_mod crc_t10dif crct10dif_common ibmvfc scsi_transport_fc scsi_tgt dm_mirror dm_region_hash dm_log dm_multipath dm_mod [ 2736.063383] CPU: 1 PID: 7128 Comm: ssh Not tainted 3.10.0-48.el7.ppc64 #1 [ 2736.063389] task: c000000131930120 ti: c0000001319a0000 task.ti: c0000001319a0000 [ 2736.063394] NIP: c00000000037efb0 LR: c0000000006c40f8 CTR: 0000000000000000 [ 2736.063399] REGS: c0000001319a3870 TRAP: 0300 Not tainted (3.10.0-48.el7.ppc64) [ 2736.063403] MSR: 8000000000009032 <SF,EE,ME,IR,DR,RI> CR: 28824242 XER: 20000000 [ 2736.063415] SOFTE: 0 [ 2736.063418] CFAR: c00000000000908c [ 2736.063421] DAR: 0000000000000000, DSISR: 40000000 [ 2736.063425] GPR00: c0000000006c40f8 c0000001319a3af0 c000000001074788 c0000001319a3bf0 GPR04: 0000000000000000 0000000000000000 0000000000000020 000000000000000a GPR08: fffffffe00000002 00000000ffff0000 0000000080000001 c000000000924888 GPR12: 0000000028824248 c000000007e00400 00001fffffa0f998 0000000000000000 GPR16: 0000000000000022 00001fffffa0f998 0000010022e92470 0000000000000000 GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR24: 0000000000000000 c000000000f4a828 00003ffffe527108 0000000000000000 GPR28: c000000000f4a730 c000000000f4a828 0000000000000000 c0000001319a3bf0 [ 2736.063498] NIP [c00000000037efb0] .__list_add+0x30/0x110 [ 2736.063504] LR [c0000000006c40f8] .rwsem_down_write_failed+0x78/0x264 [ 2736.063508] PACATMSCRATCH [800000000280f032] [ 2736.063511] Call Trace: [ 2736.063516] [c0000001319a3af0] [c0000001319a3b80] 0xc0000001319a3b80 (unreliable) [ 2736.063523] [c0000001319a3b80] [c0000000006c40f8] .rwsem_down_write_failed+0x78/0x264 [ 2736.063530] [c0000001319a3c50] [c0000000006c1bb0] .down_write+0x70/0x78 [ 2736.063536] [c0000001319a3cd0] [c0000000002e5ffc] .keyctl_get_persistent+0x20c/0x320 [ 2736.063542] [c0000001319a3dc0] [c0000000002e2388] .SyS_keyctl+0x238/0x260 [ 2736.063548] [c0000001319a3e30] [c000000000009e7c] syscall_exit+0x0/0x7c [ 2736.063553] Instruction dump: [ 2736.063556] 7c0802a6 fba1ffe8 fbc1fff0 fbe1fff8 7cbd2b78 7c9e2378 7c7f1b78 f8010010 [ 2736.063566] f821ff71 e8a50008 7fa52040 40de00c0 <e8be0000> 7fbd2840 40de0094 7fbff040 [ 2736.063579] ---[ end trace 2708241785538296 ]--- It's caused by uninitialized persistent_keyring_register_sem. The bug was introduced by commit f36f8c75, two typos are in that commit: CONFIG_KEYS_KERBEROS_CACHE should be CONFIG_PERSISTENT_KEYRINGS and krb_cache_register_sem should be persistent_keyring_register_sem. Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: David Howells <dhowells@redhat.com>
2013-12-13KEYS: Remove files generated when SYSTEM_TRUSTED_KEYRING=yKirill Tkhai1-1/+1
Always remove generated SYSTEM_TRUSTED_KEYRING files while doing make mrproper. Signed-off-by: Kirill Tkhai <tkhai@yandex.ru> Signed-off-by: David Howells <dhowells@redhat.com>
2013-12-13X.509: Fix certificate gatheringDavid Howells1-2/+3
Fix the gathering of certificates from both the source tree and the build tree to correctly calculate the pathnames of all the certificates. The problem was that if the default generated cert, signing_key.x509, didn't exist then it would not have a path attached and if it did, it would have a path attached. This means that the contents of kernel/.x509.list would change between the first compilation in a directory and the second. After the second it would remain stable because the signing_key.x509 file exists. The consequence was that the kernel would get relinked unconditionally on the second recompilation. The second recompilation would also show something like this: X.509 certificate list changed CERTS kernel/x509_certificate_list - Including cert /home/torvalds/v2.6/linux/signing_key.x509 AS kernel/system_certificates.o LD kernel/built-in.o which is why the relink would happen. Unfortunately, it isn't a simple matter of just sticking a path on the front of the filename of the certificate in the build directory as make can't then work out how to build it. So the path has to be prepended to the name for sorting and duplicate elimination and then removed for the make rule if it is in the build tree. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: David Howells <dhowells@redhat.com>
2013-12-12rcu: Remove "extern" from function declarations in kernel/rcu/rcu.hTeodora Baluta1-1/+1
Function prototypes don't need to have the "extern" keyword since this is the default behavior. Its explicit use is redundant. This commit therefore removes them. Signed-off-by: Teodora Baluta <teobaluta@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-12-12rcu/torture: Dynamically allocate SRCU output buffer to avoid overflowChen Gang1-33/+34
If the rcutorture SRCU output exceeds 4096 bytes, for example, if you have more than about 75 CPUs, it will overflow the current statically allocated buffer. This commit therefore replaces this static buffer with a dynamically buffer whose size is based on the number of CPUs. Benefits: - Avoids both buffer overflow and output truncation. - Handles an arbitrarily large number of CPUs. - Straightforward implementation. Shortcomings: - Some memory is wasted: 1 cpu now comsumes 50 - 60 bytes, and this patch provides 200 bytes. Therefore, for 1K CPUs, roughly 100KB of memory will be wasted. However, the memory is freed immediately after printing, so this wastage should not be a problem in practice. Testing (Fedora16 2 CPUs, 2GB RAM x86_64): - as module, with/without "torture_type=srcu". - build-in not boot runnable, with/without "torture_type=srcu". - build-in let boot runnable, with/without "torture_type=srcu". Signed-off-by: Chen Gang <gang.chen@asianux.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-12-12rcu: Don't activate RCU core on NO_HZ_FULL CPUsPaul E. McKenney3-0/+25
Whenever a CPU receives a scheduling-clock interrupt, RCU checks to see if the RCU core needs anything from this CPU. If so, RCU raises RCU_SOFTIRQ to carry out any needed processing. This approach has worked well historically, but it is undesirable on NO_HZ_FULL CPUs. Such CPUs are expected to spend almost all of their time in userspace, so that scheduling-clock interrupts can be disabled while there is only one runnable task on the CPU in question. Unfortunately, raising any softirq has the potential to wake up ksoftirqd, which would provide the second runnable task on that CPU, preventing disabling of scheduling-clock interrupts. What is needed instead is for RCU to leave NO_HZ_FULL CPUs alone, relying on the grace-period kthreads' quiescent-state forcing to do any needed RCU work on behalf of those CPUs. This commit therefore refrains from raising RCU_SOFTIRQ on any NO_HZ_FULL CPUs during any grace periods that have been in effect for less than one second. The one-second limit handles the case where an inappropriate workload is running on a NO_HZ_FULL CPU that features lots of scheduling-clock interrupts, but no idle or userspace time. Reported-by: Mike Galbraith <bitbucket@online.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Mike Galbraith <bitbucket@online.de> Toasted-by: Frederic Weisbecker <fweisbec@gmail.com>
2013-12-12rcu: Warn on allegedly impossible rcu_read_unlock_special() from irqLai Jiangshan1-2/+6
After commit #10f39bb1b2c1 (rcu: protect __rcu_read_unlock() against scheduler-using irq handlers), it is no longer possible to enter the main body of rcu_read_lock_special() from an NMI, interrupt, or softirq handler. In theory, this implies that the check for "in_irq() || in_serving_softirq()" must always fail, so that in theory this check could be removed entirely. In practice, this commit wraps this condition with a WARN_ON_ONCE(). If this warning never triggers, then the condition will be removed entirely. [ paulmck: And one way of triggering the WARN_ON() is if a scheduling clock interrupt occurs in an RCU read-side critical section, setting RCU_READ_UNLOCK_NEED_QS, which is handled by rcu_read_unlock_special(). Updated this commit to return if only that bit was set. ] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-12-12Merge tag 'keys-devel-20131210' of ↵Linus Torvalds3-4/+15
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull misc keyrings fixes from David Howells: "These break down into five sets: - A patch to error handling in the big_key type for huge payloads. If the payload is larger than the "low limit" and the backing store allocation fails, then big_key_instantiate() doesn't clear the payload pointers in the key, assuming them to have been previously cleared - but only one of them is. Unfortunately, the garbage collector still calls big_key_destroy() when sees one of the pointers with a weird value in it (and not NULL) which it then tries to clean up. - Three patches to fix the keyring type: * A patch to fix the hash function to correctly divide keyrings off from keys in the topology of the tree inside the associative array. This is only a problem if searching through nested keyrings - and only if the hash function incorrectly puts the a keyring outside of the 0 branch of the root node. * A patch to fix keyrings' use of the associative array. The __key_link_begin() function initially passes a NULL key pointer to assoc_array_insert() on the basis that it's holding a place in the tree whilst it does more allocation and stuff. This is only a problem when a node contains 16 keys that match at that level and we want to add an also matching 17th. This should easily be manufactured with a keyring full of keyrings (without chucking any other sort of key into the mix) - except for (a) above which makes it on average adding the 65th keyring. * A patch to fix searching down through nested keyrings, where any keyring in the set has more than 16 keyrings and none of the first keyrings we look through has a match (before the tree iteration needs to step to a more distal node). Test in keyutils test suite: http://git.kernel.org/cgit/linux/kernel/git/dhowells/keyutils.git/commit/?id=8b4ae963ed92523aea18dfbb8cab3f4979e13bd1 - A patch to fix the big_key type's use of a shmem file as its backing store causing audit messages and LSM check failures. This is done by setting S_PRIVATE on the file to avoid LSM checks on the file (access to the shmem file goes through the keyctl() interface and so is gated by the LSM that way). This isn't normally a problem if a key is used by the context that generated it - and it's currently only used by libkrb5. Test in keyutils test suite: http://git.kernel.org/cgit/linux/kernel/git/dhowells/keyutils.git/commit/?id=d9a53cbab42c293962f2f78f7190253fc73bd32e - A patch to add a generated file to .gitignore. - A patch to fix the alignment of the system certificate data such that it it works on s390. As I understand it, on the S390 arch, symbols must be 2-byte aligned because loading the address discards the least-significant bit" * tag 'keys-devel-20131210' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: KEYS: correct alignment of system_certificate_list content in assembly file Ignore generated file kernel/x509_certificate_list security: shmem: implement kernel private shmem inodes KEYS: Fix searching of nested keyrings KEYS: Fix multiple key add into associative array KEYS: Fix the keyring hash function KEYS: Pre-clear struct key on allocation
2013-12-12futex: move user address verification up to common codeLinus Torvalds1-2/+3
When debugging the read-only hugepage case, I was confused by the fact that get_futex_key() did an access_ok() only for the non-shared futex case, since the user address checking really isn't in any way specific to the private key handling. Now, it turns out that the shared key handling does effectively do the equivalent checks inside get_user_pages_fast() (it doesn't actually check the address range on x86, but does check the page protections for being a user page). So it wasn't actually a bug, but the fact that we treat the address differently for private and shared futexes threw me for a loop. Just move the check up, so that it gets done for both cases. Also, use the 'rw' parameter for the type, even if it doesn't actually matter any more (it's a historical artifact of the old racy i386 "page faults from kernel space don't check write protections"). Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-12futex: fix handling of read-only-mapped hugepagesLinus Torvalds1-1/+1
The hugepage code had the exact same bug that regular pages had in commit 7485d0d3758e ("futexes: Remove rw parameter from get_futex_key()"). The regular page case was fixed by commit 9ea71503a8ed ("futex: Fix regression with read only mappings"), but the transparent hugepage case (added in a5b338f2b0b1: "thp: update futex compound knowledge") case remained broken. Found by Dave Jones and his trinity tool. Reported-and-tested-by: Dave Jones <davej@fedoraproject.org> Cc: stable@kernel.org # v2.6.38+ Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Mel Gorman <mgorman@suse.de> Cc: Darren Hart <dvhart@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-12-11sched/fair: Rework sched_fair time accountingPeter Zijlstra1-80/+64
Christian suffers from a bad BIOS that wrecks his i5's TSC sync. This results in him occasionally seeing time going backwards - which crashes the scheduler ... Most of our time accounting can actually handle that except the most common one; the tick time update of sched_fair. There is a further problem with that code; previously we assumed that because we get a tick every TICK_NSEC our time delta could never exceed 32bits and math was simpler. However, ever since Frederic managed to get NO_HZ_FULL merged; this is no longer the case since now a task can run for a long time indeed without getting a tick. It only takes about ~4.2 seconds to overflow our u32 in nanoseconds. This means we not only need to better deal with time going backwards; but also means we need to be able to deal with large deltas. This patch reworks the entire code and uses mul_u64_u32_shr() as proposed by Andy a long while ago. We express our virtual time scale factor in a u32 multiplier and shift right and the 32bit mul_u64_u32_shr() implementation reduces to a single 32x32->64 multiply if the time delta is still short (common case). For 64bit a 64x64->128 multiply can be used if ARCH_SUPPORTS_INT128. Reported-and-Tested-by: Christian Engelmayer <cengelma@gmx.at> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: fweisbec@gmail.com Cc: Paul Turner <pjt@google.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20131118172706.GI3866@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
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