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2014-01-25introduce __fcheck_files() to fix rcu_dereference_check_fdtable(), kill ↵Oleg Nesterov1-11/+0
rcu_my_thread_group_empty() rcu_dereference_check_fdtable() looks very wrong, 1. rcu_my_thread_group_empty() was added by 844b9a8707f1 "vfs: fix RCU-lockdep false positive due to /proc" but it doesn't really fix the problem. A CLONE_THREAD (without CLONE_FILES) task can hit the same race with get_files_struct(). And otoh rcu_my_thread_group_empty() can suppress the correct warning if the caller is the CLONE_FILES (without CLONE_THREAD) task. 2. files->count == 1 check is not really right too. Even if this files_struct is not shared it is not safe to access it lockless unless the caller is the owner. Otoh, this check is sub-optimal. files->count == 0 always means it is safe to use it lockless even if files != current->files, but put_files_struct() has to take rcu_read_lock(). See the next patch. This patch removes the buggy checks and turns fcheck_files() into __fcheck_files() which uses rcu_dereference_raw(), the "unshared" callers, fget_light() and fget_raw_light(), can use it to avoid the warning from RCU-lockdep. fcheck_files() is trivially reimplemented as rcu_lockdep_assert() plus __fcheck_files(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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
2014-01-16Merge 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
2014-01-12sched_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
2013-12-17sched/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>
2013-12-15Merge 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>
2013-12-12Merge 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>
2013-12-11sched: Initialize power_orig for overlapping groupsPeter Zijlstra1-0/+1
Yinghai reported that he saw a /0 in sg_capacity on his EX parts. Make sure to always initialize power_orig now that we actually use it. Ideally build_sched_domains() -> init_sched_groups_power() would also initialize this; but for some yet unexplained reason some setups seem to miss updates there. Reported-by: Yinghai Lu <yinghai@kernel.org> Tested-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-l8ng2m9uml6fhibln8wqpom7@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-12-10KEYS: correct alignment of system_certificate_list content in assembly fileHendrik Brueckner2-4/+14
Apart from data-type specific alignment constraints, there are also architecture-specific alignment requirements. For example, on s390 symbols must be on even addresses implying a 2-byte alignment. If the system_certificate_list_end symbol is on an odd address and if this address is loaded, the least-significant bit is ignored. As a result, the load_system_certificate_list() fails to load the certificates because of a wrong certificate length calculation. To be safe, align system_certificate_list on an 8-byte boundary. Also improve the length calculation of the system_certificate_list content. Introduce a system_certificate_list_size (8-byte aligned because of unsigned long) variable that stores the length. Let the linker calculate this size by introducing a start and end label for the certificate content. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: David Howells <dhowells@redhat.com>
2013-12-10Ignore generated file kernel/x509_certificate_listRusty Russell1-0/+1
$ git status # On branch pending-rebases # Untracked files: # (use "git add <file>..." to include in what will be committed) # # kernel/x509_certificate_list nothing added to commit but untracked files present (use "git add" to track) $ Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David Howells <dhowells@redhat.com>
2013-12-07PCI: Disable Bus Master only on kexec rebootKhalid Aziz1-0/+4
Add a flag to tell the PCI subsystem that kernel is shutting down in preparation to kexec a kernel. Add code in PCI subsystem to use this flag to clear Bus Master bit on PCI devices only in case of kexec reboot. This fixes a power-off problem on Acer Aspire V5-573G and likely other machines and avoids any other issues caused by clearing Bus Master bit on PCI devices in normal shutdown path. The problem was introduced by b566a22c2332 ("PCI: disable Bus Master on PCI device shutdown"). This patch is based on discussion at http://marc.info/?l=linux-pci&m=138425645204355&w=2 Link: https://bugzilla.kernel.org/show_bug.cgi?id=63861 Reported-by: Chang Liu <cl91tp@gmail.com> Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Konstantin Khlebnikov <koct9i@gmail.com> Cc: stable@vger.kernel.org # v3.5+
2013-12-06cgroup: fix cgroup_create() error handling pathTejun Heo1-10/+21
ae7f164a09 ("cgroup: move cgroup->subsys[] assignment to online_css()") moved cgroup->subsys[] assignements later in cgroup_create() but didn't update error handling path accordingly leading to the following oops and leaking later css's after an online_css() failure. The oops is from cgroup destruction path being invoked on the partially constructed cgroup which is not ready to handle empty slots in cgrp->subsys[] array. BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: [<ffffffff810eeaa8>] cgroup_destroy_locked+0x118/0x2f0 PGD a780a067 PUD aadbe067 PMD 0 Oops: 0000 [#1] SMP Modules linked in: CPU: 6 PID: 7360 Comm: mkdir Not tainted 3.13.0-rc2+ #69 Hardware name: task: ffff8800b9dbec00 ti: ffff8800a781a000 task.ti: ffff8800a781a000 RIP: 0010:[<ffffffff810eeaa8>] [<ffffffff810eeaa8>] cgroup_destroy_locked+0x118/0x2f0 RSP: 0018:ffff8800a781bd98 EFLAGS: 00010282 RAX: ffff880586903878 RBX: ffff880586903800 RCX: ffff880586903820 RDX: ffff880586903860 RSI: ffff8800a781bdb0 RDI: ffff880586903820 RBP: ffff8800a781bde8 R08: ffff88060e0b8048 R09: ffffffff811d7bc1 R10: 000000000000008c R11: 0000000000000001 R12: ffff8800a72286c0 R13: 0000000000000000 R14: ffffffff81cf7a40 R15: 0000000000000001 FS: 00007f60ecda57a0(0000) GS:ffff8806272c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 00000000a7a03000 CR4: 00000000000007e0 Stack: ffff880586903860 ffff880586903910 ffff8800a72286c0 ffff880586903820 ffffffff81cf7a40 ffff880586903800 ffff88060e0b8018 ffffffff81cf7a40 ffff8800b9dbec00 ffff8800b9dbf098 ffff8800a781bec8 ffffffff810ef5bf Call Trace: [<ffffffff810ef5bf>] cgroup_mkdir+0x55f/0x5f0 [<ffffffff811c90ae>] vfs_mkdir+0xee/0x140 [<ffffffff811cb07e>] SyS_mkdirat+0x6e/0xf0 [<ffffffff811c6a19>] SyS_mkdir+0x19/0x20 [<ffffffff8169e569>] system_call_fastpath+0x16/0x1b This patch moves reference bumping inside online_css() loop, clears css_ar[] as css's are brought online successfully, and updates err_destroy path so that either a css is fully online and destroyed by cgroup_destroy_locked() or the error path frees it. This creates a duplicate css free logic in the error path but it will be cleaned up soon. v2: Li pointed out that cgroup_destroy_locked() would do NULL-deref if invoked with a cgroup which doesn't have all css's populated. Update cgroup_destroy_locked() so that it skips NULL css's. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Reported-by: Vladimir Davydov <vdavydov@parallels.com> Cc: stable@vger.kernel.org # v3.12+
2013-12-06Merge tag 'trace-fixes-3.13-rc2' of ↵Linus Torvalds2-10/+3
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fix from Steven Rostedt: "A regression showed up that there's a large delay when enabling all events. This was prevalent when FTRACE_SELFTEST was enabled which enables all events several times, and caused the system bootup to pause for over a minute. This was tracked down to an addition of a synchronize_sched() performed when system call tracepoints are unregistered. The synchronize_sched() is needed between the unregistering of the system call tracepoint and a deletion of a tracing instance buffer. But placing the synchronize_sched() in the unreg of *every* system call tracepoint is a bit overboard. A single synchronize_sched() before the deletion of the instance is sufficient" * tag 'trace-fixes-3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Only run synchronize_sched() at instance deletion time
2013-12-05tracing: Only run synchronize_sched() at instance deletion timeSteven Rostedt2-10/+3
It has been reported that boot up with FTRACE_SELFTEST enabled can take a very long time. There can be stalls of over a minute. This was tracked down to the synchronize_sched() called when a system call event is disabled. As the self tests enable and disable thousands of events, this makes the synchronize_sched() get called thousands of times. The synchornize_sched() was added with d562aff93bfb53 "tracing: Add support for SOFT_DISABLE to syscall events" which caused this regression (added in 3.13-rc1). The synchronize_sched() is to protect against the events being accessed when a tracer instance is being deleted. When an instance is being deleted all the events associated to it are unregistered. The synchronize_sched() makes sure that no more users are running when it finishes. Instead of calling synchronize_sched() for all syscall events, we only need to call it once, after the events are unregistered and before the instance is deleted. The event_mutex is held during this action to prevent new users from enabling events. Link: http://lkml.kernel.org/r/20131203124120.427b9661@gandalf.local.home Reported-by: Petr Mladek <pmladek@suse.cz> Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com> Acked-by: Petr Mladek <pmladek@suse.cz> Tested-by: Petr Mladek <pmladek@suse.cz> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-12-04Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds5-19/+32
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fixes from Thomas Gleixner: - timekeeping: Cure a subtle drift issue on GENERIC_TIME_VSYSCALL_OLD - nohz: Make CONFIG_NO_HZ=n and nohz=off command line option behave the same way. Fixes a long standing load accounting wreckage. - clocksource/ARM: Kconfig update to avoid ARM=n wreckage - clocksource/ARM: Fixlets for the AT91 and SH clocksource/clockevents - Trivial documentation update and kzalloc conversion from akpms pile * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: nohz: Fix another inconsistency between CONFIG_NO_HZ=n and nohz=off time: Fix 1ns/tick drift w/ GENERIC_TIME_VSYSCALL_OLD clocksource: arm_arch_timer: Hide eventstream Kconfig on non-ARM clocksource: sh_tmu: Add clk_prepare/unprepare support clocksource: sh_tmu: Release clock when sh_tmu_register() fails clocksource: sh_mtu2: Add clk_prepare/unprepare support clocksource: sh_mtu2: Release clock when sh_mtu2_register() fails ARM: at91: rm9200: switch back to clockevents_config_and_register tick: Document tick_do_timer_cpu timer: Convert kmalloc_node(...GFP_ZERO...) to kzalloc_node(...) NOHZ: Check for nohz active instead of nohz enabled
2013-12-02Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fixes from Thomas Gleixner: - Correction of fuzzy and fragile IRQ_RETVAL macro - IRQ related resume fix affecting only XEN - ARM/GIC fix for chained GIC controllers * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip: Gic: fix boot for chained gics irq: Enable all irqs unconditionally in irq_resume genirq: Correct fuzzy and fragile IRQ_RETVAL() definition
2013-12-02Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2-7/+28
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "Various smaller fixlets, all over the place" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/doc: Fix generation of device-drivers sched: Expose preempt_schedule_irq() sched: Fix a trivial typo in comments sched: Remove unused variable in 'struct sched_domain' sched: Avoid NULL dereference on sd_busy sched: Check sched_domain before computing group power MAINTAINERS: Update file patterns in the lockdep and scheduler entries
2013-12-02Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds2-9/+7
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "Misc kernel and tooling fixes" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tools lib traceevent: Fix conversion of pointer to integer of different size perf/trace: Properly use u64 to hold event_id perf: Remove fragile swevent hlist optimization ftrace, perf: Avoid infinite event generation loop tools lib traceevent: Fix use of multiple options in processing field perf header: Fix possible memory leaks in process_group_desc() perf header: Fix bogus group name perf tools: Tag thread comm as overriden
2013-11-29Merge branch 'for-3.13-fixes' of ↵Linus Torvalds1-13/+37
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq Pull workqueue fixes from Tejun Heo: "This contains one important fix. The NUMA support added a while back broke ordering guarantees on ordered workqueues. It was enforced by having single frontend interface with @max_active == 1 but the NUMA support puts multiple interfaces on unbound workqueues on NUMA machines thus breaking the ordered guarantee. This is fixed by disabling NUMA support on ordered workqueues. The above and a couple other patches were sitting in for-3.12-fixes but I forgot to push that out, so they ended up waiting a bit too long. My aplogies. Other fixes are minor" * 'for-3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: fix pool ID allocation leakage and remove BUILD_BUG_ON() in init_workqueues workqueue: fix comment typo for __queue_work() workqueue: fix ordered workqueues in NUMA setups workqueue: swap set_cpus_allowed_ptr() and PF_NO_SETAFFINITY
2013-11-29Merge branch 'for-3.13-fixes' of ↵Linus Torvalds2-6/+37
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: "Fixes for three issues. - cgroup destruction path could swamp system_wq possibly leading to deadlock. This actually seems to happen in the wild with memcg because memcg destruction path adds nested dependency on system_wq. Resolved by isolating cgroup destruction work items on its dedicated workqueue. - Possible locking context deadlock through seqcount reported by lockdep - Memory leak under certain conditions" * 'for-3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: fix cgroup_subsys_state leak for seq_files cpuset: Fix memory allocator deadlock cgroup: use a dedicated workqueue for cgroup destruction
2013-11-29nohz: Fix another inconsistency between CONFIG_NO_HZ=n and nohz=offThomas Gleixner1-1/+3
If CONFIG_NO_HZ=n tick_nohz_get_sleep_length() returns NSEC_PER_SEC/HZ. If CONFIG_NO_HZ=y and the nohz functionality is disabled via the command line option "nohz=off" or not enabled due to missing hardware support, then tick_nohz_get_sleep_length() returns 0. That happens because ts->sleep_length is never set in that case. Set it to NSEC_PER_SEC/HZ when the NOHZ mode is inactive. Reported-by: Michal Hocko <mhocko@suse.cz> Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-11-28kernel/extable: fix address-checks for core_kernel and init areasHelge Deller1-2/+2
The init_kernel_text() and core_kernel_text() functions should not include the labels _einittext and _etext when checking if an address is inside the .text or .init sections. Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-27cgroup: fix cgroup_subsys_state leak for seq_filesTejun Heo1-1/+4
If a cgroup file implements either read_map() or read_seq_string(), such file is served using seq_file by overriding file->f_op to cgroup_seqfile_operations, which also overrides the release method to single_release() from cgroup_file_release(). Because cgroup_file_open() didn't use to acquire any resources, this used to be fine, but since f7d58818ba42 ("cgroup: pin cgroup_subsys_state when opening a cgroupfs file"), cgroup_file_open() pins the css (cgroup_subsys_state) which is put by cgroup_file_release(). The patch forgot to update the release path for seq_files and each open/release cycle leaks a css reference. Fix it by updating cgroup_file_release() to also handle seq_files and using it for seq_file release path too. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org # v3.12
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