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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>
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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>
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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>
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- 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>
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Refresh the tree with the latest fixes, before applying new changes.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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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
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* 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().
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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
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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
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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>
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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>
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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
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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>
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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'
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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
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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
...
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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>
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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>
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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>
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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
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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
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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>
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Merge Linux 3.13-rc4, to refresh this rather old tree with the latest fixes.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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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>
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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>
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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>
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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>
|
|
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>
|
|
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>
|
|
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
|
|
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>
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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>
|
|
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>
|
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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
|
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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>
|
|
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>
|
|
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>
|
|
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>
|
|
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>
|
|
$ 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>
|
|
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+
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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+
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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
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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>
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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
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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
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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
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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
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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
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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
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