ARM: DMA: ensure that old section mappings are flushed from the TLB

When setting up the CMA region, we must ensure that the old section
mappings are flushed from the TLB before replacing them with page
tables, otherwise we can suffer from mismatched aliases if the CPU
speculatively prefetches from these mappings at an inopportune time.

A mismatched alias can occur when the TLB contains a section mapping,
but a subsequent prefetch causes it to load a page table mapping,
resulting in the possibility of the TLB containing two matching
mappings for the same virtual address region.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 8100/1: Fix preemption disable in iwmmxt_task_enable()

commit 431a84b1a4f7d1a0085d5b91330c5053cc8e8b12
 ("ARM: 8034/1: Disable preemption in iwmmxt_task_enable()")
introduced macros {inc,dec}_preempt_count to iwmmxt_task_enable
to make it run with preemption disabled.

Unfortunately, other functions in iwmmxt.S also use concan_{save,dump,load}
sections located in iwmmxt_task_enable() to deal with iWMMXt coprocessor.
This causes an unbalanced preempt_count due to excessive dec_preempt_count
and destroyed return addresses in callers of concan_ labels due to a register
collision:

Linux version 3.16.0-rc3-00062-gd92a333-dirty (jef@armhf) (gcc version 4.8.3 (Debian 4.8.3-4) ) #5 PREEMPT Thu Jul 3 19:46:39 CEST 2014
CPU: ARMv7 Processor [560f5815] revision 5 (ARMv7), cr=10c5387d
CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
Machine model: SolidRun CuBox
...
PJ4 iWMMXt v2 coprocessor enabled.
...
Unable to handle kernel paging request at virtual address fffffffe
pgd = bb25c000
[fffffffe] *pgd=3bfde821, *pte=00000000, *ppte=00000000
Internal error: Oops: 80000007 [#1] PREEMPT ARM
Modules linked in:
CPU: 0 PID: 62 Comm: startpar Not tainted 3.16.0-rc3-00062-gd92a333-dirty #5
task: bb230b80 ti: bb256000 task.ti: bb256000
PC is at 0xfffffffe
LR is at iwmmxt_task_copy+0x44/0x4c
pc : [<fffffffe>]    lr : [<800130ac>]    psr: 40000033
sp : bb257de8  ip : 00000013  fp : bb257ea4
r10: bb256000  r9 : fffffdfe  r8 : 76e898e6
r7 : bb257ec8  r6 : bb256000  r5 : 7ea12760  r4 : 000000a0
r3 : ffffffff  r2 : 00000003  r1 : bb257df8  r0 : 00000000
Flags: nZcv  IRQs on  FIQs on  Mode SVC_32  ISA Thumb  Segment user
Control: 10c5387d  Table: 3b25c019  DAC: 00000015
Process startpar (pid: 62, stack limit = 0xbb256248)

This patch fixes the issue by moving concan_{save,dump,load} into separate
code sections and make iwmmxt_task_enable() call them in the same way the
other functions use concan_ symbols. The test for valid ownership is moved
to concan_save and is safe for the other user of it, iwmmxt_task_disable().
The register collision is also resolved by moving concan_ symbols as
{inc,dec}_preempt_count are now local to iwmmxt_task_enable().

Fixes: 431a84b1a4f7 ("ARM: 8034/1: Disable preemption in iwmmxt_task_enable()")

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
iio: buffer: Fix demux table creation

When creating the demux table we need to iterate over the selected scan mask for
the buffer to get the samples which should be copied to destination buffer.
Right now the code uses the mask which contains all active channels, which means
the demux table contains entries which causes it to copy all the samples from
source to destination buffer one by one without doing any demuxing.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Cc: Stable@vger.kernel.org
iio:bma180: Fix scale factors to report correct acceleration units

The userspace interface for acceleration sensors is documented as using
m/s^2 units [Documentation/ABI/testing/sysfs-bus-iio]

The fullscale raw values for the BMA80 corresponds to -/+ 1, 1.5, 2, etc G
depending on the selected mode.

The scale table was converting to G rather than m/s^2.
Change the scaling table to match the documented interface.

See commit 71702e6e, iio: mma8452: Use correct acceleration units,
for a related fix.

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Cc: Stable@vger.kernel.org
iio:bma180: Missing check for frequency fractional part

val2 should be zero

This will make no difference for correct inputs but will reject
incorrect ones with a decimal part in the value written to the sysfs
interface.

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Cc: Stable@vger.kernel.org
Merge tag 'iio-fixes-for-3.16e' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus

Jonathan writes:

Fifth set of fixes for IIO in the 3.16 cycle.

One nasty one that has been around a long time and a couple of non compliant
ABI fixes.

* The demux code used to split out desired channels for devices that only
  support reading sets of channels at one time had a bug where it was
  building it's conversion tables against the wrong bitmap resulting in
  it never actually demuxing anything.  This is an old bug, but will be
  effecting an increasing number of drivers as it is often used to avoid
  some fiddly code in the individual drivers.

* bma180 and mma8452 weren't obeying the ABI wrt to units for acceleration.
  Were in G rather than m/s^2. A little input check was missing from bma180
  that might lead to acceptance of incorrect values.  This last one is minor
  but might lead to incorrect userspace code working and problems in the
  future.
staging: rtl8723au: rtw_resume(): release semaphore before exit on error

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sched_clock: Avoid corrupting hrtimer tree during suspend

During suspend we call sched_clock_poll() to update the epoch and
accumulated time and reprogram the sched_clock_timer to fire
before the next wrap-around time. Unfortunately,
sched_clock_poll() doesn't restart the timer, instead it relies
on the hrtimer layer to do that and during suspend we aren't
calling that function from the hrtimer layer. Instead, we're
reprogramming the expires time while the hrtimer is enqueued,
which can cause the hrtimer tree to be corrupted. Furthermore, we
restart the timer during suspend but we update the epoch during
resume which seems counter-intuitive.

Let's fix this by saving the accumulated state and canceling the
timer during suspend. On resume we can update the epoch and
restart the timer similar to what we would do if we were starting
the clock for the first time.

Fixes: a08ca5d1089d "sched_clock: Use an hrtimer instead of timer"
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1406174630-23458-1-git-send-email-john.stultz@linaro.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
ARM: 8112/1: only select ARM_PATCH_PHYS_VIRT if MMU is enabled

This fixes the following warning:

	warning: (ARCH_MULTIPLATFORM && ARCH_INTEGRATOR && ARCH_SHMOBILE_LEGACY) selects ARM_PATCH_PHYS_VIRT which has unmet direct dependencies (!XIP_KERNEL && MMU && (!ARCH_REALVIEW || !SPARSEMEM))

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
staging: vt6655: Fix Warning on boot handle_irq_event_percpu.

WARNING: CPU: 0 PID: 929 at /home/apw/COD/linux/kernel/irq/handle.c:147 handle_irq_event_percpu+0x1d1/0x1e0()
irq 17 handler device_intr+0x0/0xa80 [vt6655_stage] enabled interrupts

Using spin_lock_irqsave appears to fix this.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: vt6655: Fix disassociated messages every 10 seconds

byReAssocCount is incremented every second resulting in
disassociated message being send every 10 seconds whether
connection or not.

byReAssocCount should only advance while eCommandState
is in WLAN_ASSOCIATE_WAIT

Change existing scope to if condition.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86_64/entry/xen: Do not invoke espfix64 on Xen

This moves the espfix64 logic into native_iret.  To make this work,
it gets rid of the native patch for INTERRUPT_RETURN:
INTERRUPT_RETURN on native kernels is now 'jmp native_iret'.

This changes the 16-bit SS behavior on Xen from OOPSing to leaking
some bits of the Xen hypervisor's RSP (I think).

[ hpa: this is a nonzero cost on native, but probably not enough to
  measure. Xen needs to fix this in their own code, probably doing
  something equivalent to espfix64. ]

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/7b8f1d8ef6597cb16ae004a43c56980a7de3cf94.1406129132.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>
ARM: fix alignment of keystone page table fixup

If init_mm.brk is not section aligned, the LPAE fixup code will miss
updating the final PMD.  Fix this by aligning map_end.

Fixes: a77e0c7b2774 ("ARM: mm: Recreate kernel mappings in early_paging_init()")
Cc: <stable@vger.kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 8115/1: LPAE: reduce damage caused by idmap to virtual memory layout

On LPAE, each level 1 (pgd) page table entry maps 1GiB, and the level 2
(pmd) entries map 2MiB.

When the identity mapping is created on LPAE, the pgd pointers are copied
from the swapper_pg_dir.  If we find that we need to modify the contents
of a pmd, we allocate a new empty pmd table and insert it into the
appropriate 1GB slot, before then filling it with the identity mapping.

However, if the 1GB slot covers the kernel lowmem mappings, we obliterate
those mappings.

When replacing a PMD, first copy the old PMD contents to the new PMD, so
that we preserve the existing mappings, particularly the mappings of the
kernel itself.

[rewrote commit message and added code comment -- rmk]

Fixes: ae2de101739c ("ARM: LPAE: Add identity mapping support for the 3-level page table format")
Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: nomadik: fix up double inversion in DT

The GPIO pin connected to card detect was inverted twice: once by
the argument to the GPIO line itself where it was magically marked
as active low by the flag GPIO_ACTIVE_LOW (0x01) in the third cell,
and also marked active low AGAIN by explicitly stating
"cd-inverted" (a deprecated method).

After commit 78f87df2b4f8760954d7d80603d0cfcbd4759683
"mmc: mmci: Use the common mmc DT parser" this results in the
line being inverted twice so it was effectively uninverted, while
the old code would not have this effect, instead disregarding the
flag on the GPIO line altogether, which is a bug. I admit the
semantics may be unclear but inverting twice is as good a
definition as any on how this should work.

So fix up the buggy device tree. Use proper #includes so the DTS
is clear and readable.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
MAINTAINERS: Update Tegra Git URL

swarren/linux-tegra.git is a stale location; it has moved to
tegra/linux.git.

While the git protocol re-directs to the new location, HTTP does not.
Besides, MAINTAINERS should contain the canonical URL.

Signed-off-by: Andreas Färber <afaerber@suse.de>
[swarren, updated commit message]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
direct-io: fix AIO regression

The direct-io.c rewrite to use the iov_iter infrastructure stopped updating
the size field in struct dio_submit, and thus rendered the check for
allowing asynchronous completions to always return false.  Fix this by
comparing it to the count of bytes in the iov_iter instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Tim Chen <tim.c.chen@linux.intel.com>
Tested-by: Tim Chen <tim.c.chen@linux.intel.com>
vfs: fix check for fallocate on active swapfile

Fix the broken check for calling sys_fallocate() on an active swapfile,
introduced by commit 0790b31b69374ddadefe ("fs: disallow all fallocate
operation on active swapfile").

Signed-off-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
timer: Fix lock inversion between hrtimer_bases.lock and scheduler locks

clockevents_increase_min_delta() calls printk() from under
hrtimer_bases.lock. That causes lock inversion on scheduler locks because
printk() can call into the scheduler. Lockdep puts it as:

======================================================
[ INFO: possible circular locking dependency detected ]
3.15.0-rc8-06195-g939f04b #2 Not tainted
-------------------------------------------------------
trinity-main/74 is trying to acquire lock:
 (&port_lock_key){-.....}, at: [<811c60be>] serial8250_console_write+0x8c/0x10c

but task is already holding lock:
 (hrtimer_bases.lock){-.-...}, at: [<8103caeb>] hrtimer_try_to_cancel+0x13/0x66

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #5 (hrtimer_bases.lock){-.-...}:
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e
       [<8103c918>] __hrtimer_start_range_ns+0x1c/0x197
       [<8107ec20>] perf_swevent_start_hrtimer.part.41+0x7a/0x85
       [<81080792>] task_clock_event_start+0x3a/0x3f
       [<810807a4>] task_clock_event_add+0xd/0x14
       [<8108259a>] event_sched_in+0xb6/0x17a
       [<810826a2>] group_sched_in+0x44/0x122
       [<81082885>] ctx_sched_in.isra.67+0x105/0x11f
       [<810828e6>] perf_event_sched_in.isra.70+0x47/0x4b
       [<81082bf6>] __perf_install_in_context+0x8b/0xa3
       [<8107eb8e>] remote_function+0x12/0x2a
       [<8105f5af>] smp_call_function_single+0x2d/0x53
       [<8107e17d>] task_function_call+0x30/0x36
       [<8107fb82>] perf_install_in_context+0x87/0xbb
       [<810852c9>] SYSC_perf_event_open+0x5c6/0x701
       [<810856f9>] SyS_perf_event_open+0x17/0x19
       [<8142f8ee>] syscall_call+0x7/0xb

-> #4 (&ctx->lock){......}:
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f04c>] _raw_spin_lock+0x21/0x30
       [<81081df3>] __perf_event_task_sched_out+0x1dc/0x34f
       [<8142cacc>] __schedule+0x4c6/0x4cb
       [<8142cae0>] schedule+0xf/0x11
       [<8142f9a6>] work_resched+0x5/0x30

-> #3 (&rq->lock){-.-.-.}:
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f04c>] _raw_spin_lock+0x21/0x30
       [<81040873>] __task_rq_lock+0x33/0x3a
       [<8104184c>] wake_up_new_task+0x25/0xc2
       [<8102474b>] do_fork+0x15c/0x2a0
       [<810248a9>] kernel_thread+0x1a/0x1f
       [<814232a2>] rest_init+0x1a/0x10e
       [<817af949>] start_kernel+0x303/0x308
       [<817af2ab>] i386_start_kernel+0x79/0x7d

-> #2 (&p->pi_lock){-.-...}:
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e
       [<810413dd>] try_to_wake_up+0x1d/0xd6
       [<810414cd>] default_wake_function+0xb/0xd
       [<810461f3>] __wake_up_common+0x39/0x59
       [<81046346>] __wake_up+0x29/0x3b
       [<811b8733>] tty_wakeup+0x49/0x51
       [<811c3568>] uart_write_wakeup+0x17/0x19
       [<811c5dc1>] serial8250_tx_chars+0xbc/0xfb
       [<811c5f28>] serial8250_handle_irq+0x54/0x6a
       [<811c5f57>] serial8250_default_handle_irq+0x19/0x1c
       [<811c56d8>] serial8250_interrupt+0x38/0x9e
       [<810510e7>] handle_irq_event_percpu+0x5f/0x1e2
       [<81051296>] handle_irq_event+0x2c/0x43
       [<81052cee>] handle_level_irq+0x57/0x80
       [<81002a72>] handle_irq+0x46/0x5c
       [<810027df>] do_IRQ+0x32/0x89
       [<8143036e>] common_interrupt+0x2e/0x33
       [<8142f23c>] _raw_spin_unlock_irqrestore+0x3f/0x49
       [<811c25a4>] uart_start+0x2d/0x32
       [<811c2c04>] uart_write+0xc7/0xd6
       [<811bc6f6>] n_tty_write+0xb8/0x35e
       [<811b9beb>] tty_write+0x163/0x1e4
       [<811b9cd9>] redirected_tty_write+0x6d/0x75
       [<810b6ed6>] vfs_write+0x75/0xb0
       [<810b7265>] SyS_write+0x44/0x77
       [<8142f8ee>] syscall_call+0x7/0xb

-> #1 (&tty->write_wait){-.....}:
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e
       [<81046332>] __wake_up+0x15/0x3b
       [<811b8733>] tty_wakeup+0x49/0x51
       [<811c3568>] uart_write_wakeup+0x17/0x19
       [<811c5dc1>] serial8250_tx_chars+0xbc/0xfb
       [<811c5f28>] serial8250_handle_irq+0x54/0x6a
       [<811c5f57>] serial8250_default_handle_irq+0x19/0x1c
       [<811c56d8>] serial8250_interrupt+0x38/0x9e
       [<810510e7>] handle_irq_event_percpu+0x5f/0x1e2
       [<81051296>] handle_irq_event+0x2c/0x43
       [<81052cee>] handle_level_irq+0x57/0x80
       [<81002a72>] handle_irq+0x46/0x5c
       [<810027df>] do_IRQ+0x32/0x89
       [<8143036e>] common_interrupt+0x2e/0x33
       [<8142f23c>] _raw_spin_unlock_irqrestore+0x3f/0x49
       [<811c25a4>] uart_start+0x2d/0x32
       [<811c2c04>] uart_write+0xc7/0xd6
       [<811bc6f6>] n_tty_write+0xb8/0x35e
       [<811b9beb>] tty_write+0x163/0x1e4
       [<811b9cd9>] redirected_tty_write+0x6d/0x75
       [<810b6ed6>] vfs_write+0x75/0xb0
       [<810b7265>] SyS_write+0x44/0x77
       [<8142f8ee>] syscall_call+0x7/0xb

-> #0 (&port_lock_key){-.....}:
       [<8104a62d>] __lock_acquire+0x9ea/0xc6d
       [<8104a942>] lock_acquire+0x92/0x101
       [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e
       [<811c60be>] serial8250_console_write+0x8c/0x10c
       [<8104e402>] call_console_drivers.constprop.31+0x87/0x118
       [<8104f5d5>] console_unlock+0x1d7/0x398
       [<8104fb70>] vprintk_emit+0x3da/0x3e4
       [<81425f76>] printk+0x17/0x19
       [<8105bfa0>] clockevents_program_min_delta+0x104/0x116
       [<8105c548>] clockevents_program_event+0xe7/0xf3
       [<8105cc1c>] tick_program_event+0x1e/0x23
       [<8103c43c>] hrtimer_force_reprogram+0x88/0x8f
       [<8103c49e>] __remove_hrtimer+0x5b/0x79
       [<8103cb21>] hrtimer_try_to_cancel+0x49/0x66
       [<8103cb4b>] hrtimer_cancel+0xd/0x18
       [<8107f102>] perf_swevent_cancel_hrtimer.part.60+0x2b/0x30
       [<81080705>] task_clock_event_stop+0x20/0x64
       [<81080756>] task_clock_event_del+0xd/0xf
       [<81081350>] event_sched_out+0xab/0x11e
       [<810813e0>] group_sched_out+0x1d/0x66
       [<81081682>] ctx_sched_out+0xaf/0xbf
       [<81081e04>] __perf_event_task_sched_out+0x1ed/0x34f
       [<8142cacc>] __schedule+0x4c6/0x4cb
       [<8142cae0>] schedule+0xf/0x11
       [<8142f9a6>] work_resched+0x5/0x30

other info that might help us debug this:

Chain exists of:
  &port_lock_key --> &ctx->lock --> hrtimer_bases.lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(hrtimer_bases.lock);
                               lock(&ctx->lock);
                               lock(hrtimer_bases.lock);
  lock(&port_lock_key);

 *** DEADLOCK ***

4 locks held by trinity-main/74:
 #0:  (&rq->lock){-.-.-.}, at: [<8142c6f3>] __schedule+0xed/0x4cb
 #1:  (&ctx->lock){......}, at: [<81081df3>] __perf_event_task_sched_out+0x1dc/0x34f
 #2:  (hrtimer_bases.lock){-.-...}, at: [<8103caeb>] hrtimer_try_to_cancel+0x13/0x66
 #3:  (console_lock){+.+...}, at: [<8104fb5d>] vprintk_emit+0x3c7/0x3e4

stack backtrace:
CPU: 0 PID: 74 Comm: trinity-main Not tainted 3.15.0-rc8-06195-g939f04b #2
 00000000 81c3a310 8b995c14 81426f69 8b995c44 81425a99 8161f671 8161f570
 8161f538 8161f559 8161f538 8b995c78 8b142bb0 00000004 8b142fdc 8b142bb0
 8b995ca8 8104a62d 8b142fac 000016f2 81c3a310 00000001 00000001 00000003
Call Trace:
 [<81426f69>] dump_stack+0x16/0x18
 [<81425a99>] print_circular_bug+0x18f/0x19c
 [<8104a62d>] __lock_acquire+0x9ea/0xc6d
 [<8104a942>] lock_acquire+0x92/0x101
 [<811c60be>] ? serial8250_console_write+0x8c/0x10c
 [<811c6032>] ? wait_for_xmitr+0x76/0x76
 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e
 [<811c60be>] ? serial8250_console_write+0x8c/0x10c
 [<811c60be>] serial8250_console_write+0x8c/0x10c
 [<8104af87>] ? lock_release+0x191/0x223
 [<811c6032>] ? wait_for_xmitr+0x76/0x76
 [<8104e402>] call_console_drivers.constprop.31+0x87/0x118
 [<8104f5d5>] console_unlock+0x1d7/0x398
 [<8104fb70>] vprintk_emit+0x3da/0x3e4
 [<81425f76>] printk+0x17/0x19
 [<8105bfa0>] clockevents_program_min_delta+0x104/0x116
 [<8105cc1c>] tick_program_event+0x1e/0x23
 [<8103c43c>] hrtimer_force_reprogram+0x88/0x8f
 [<8103c49e>] __remove_hrtimer+0x5b/0x79
 [<8103cb21>] hrtimer_try_to_cancel+0x49/0x66
 [<8103cb4b>] hrtimer_cancel+0xd/0x18
 [<8107f102>] perf_swevent_cancel_hrtimer.part.60+0x2b/0x30
 [<81080705>] task_clock_event_stop+0x20/0x64
 [<81080756>] task_clock_event_del+0xd/0xf
 [<81081350>] event_sched_out+0xab/0x11e
 [<810813e0>] group_sched_out+0x1d/0x66
 [<81081682>] ctx_sched_out+0xaf/0xbf
 [<81081e04>] __perf_event_task_sched_out+0x1ed/0x34f
 [<8104416d>] ? __dequeue_entity+0x23/0x27
 [<81044505>] ? pick_next_task_fair+0xb1/0x120
 [<8142cacc>] __schedule+0x4c6/0x4cb
 [<81047574>] ? trace_hardirqs_off_caller+0xd7/0x108
 [<810475b0>] ? trace_hardirqs_off+0xb/0xd
 [<81056346>] ? rcu_irq_exit+0x64/0x77

Fix the problem by using printk_deferred() which does not call into the
scheduler.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
dm bufio: fully initialize shrinker

1d3d4437eae1 ("vmscan: per-node deferred work") added a flags field to
struct shrinker assuming that all shrinkers were zero filled.  The dm
bufio shrinker is not zero filled, which leaves arbitrary kmalloc() data
in flags.  So far the only defined flags bit is SHRINKER_NUMA_AWARE.
But there are proposed patches which add other bits to shrinker.flags
(e.g. memcg awareness).

Rather than simply initializing the shrinker, this patch uses kzalloc()
when allocating the dm_bufio_client to ensure that the embedded shrinker
and any other similar structures are zeroed.

This fixes theoretical over aggressive shrinking of dm bufio objects.
If the uninitialized dm_bufio_client.shrinker.flags contains
SHRINKER_NUMA_AWARE then shrink_slab() would call the dm shrinker for
each numa node rather than just once.  This has been broken since 3.12.

Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # v3.12+