Impact: extend the scope of hung-task checks

Changed the default value of hung_task_check_count to PID_MAX_LIMIT.
hung_task_batch_count added to put an upper bound on the critical
section. Every hung_task_batch_count checks, the rcu lock is never
held for a too long time.

Keeping the critical section small minimizes time preemption is disabled
and keeps rcu grace periods small.

To prevent following a stale pointer, get_task_struct is called on g and t.
To verify that g and t have not been unhashed while outside the critical
section, the task states are checked.

The design was proposed by Frédéric Weisbecker.
Signed-off-by: Mandeep Singh Baines <msb@google.com>
Suggested-by: Frédéric Weisbecker <fweisbec@gmail.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

The definition of spawn_softlockup_task in sched.h became
unnecessary once it was converted to the early_initcall()
interface.
Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: fix potential false panic

A potential race exists if sysctl_hung_task_timeout_secs is reset to 0
while inside check_hung_uniterruptible_tasks(). If check_task() is
entered, a comparison with 0 will result in a false hung_task being
detected.

If sysctl_hung_task_panic is set, the system will panic.
Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Fixes the following compile error:

 kernel/fork.c:1049: error: 'struct task_struct' has no member named 'last_switch_count'
 kernel/fork.c:1050: error: 'struct task_struct' has no member named 'last_switch_timestamp'
Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Decoupling allows:

* hung tasks check to happen at very low priority

* hung tasks check and softlockup to be enabled/disabled independently
  at compile and/or run-time

* individual panic settings to be enabled disabled independently
  at compile and/or run-time

* softlockup threshold to be reduced without increasing hung tasks
  poll frequency (hung task check is expensive relative to softlock watchdog)

* hung task check to be zero over-head when disabled at run-time
Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Move RCU Kconfig options from top-level menu to an "RCU Subsystem"
menu under the "General Setup" menu.
Signed-off-by: Mike Travis <travis@sgi.com>
Tested-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

At run-time, if softlockup_thresh is changed to a much lower value,
touch_timestamp is likely to be much older than the new softlock_thresh.

This will cause a false softlockup to be detected. If softlockup_panic
is enabled, the system will panic.

The fix is to touch all watchdogs before changing softlockup_thresh.
Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: reduce memory footprint

add __cpuinit to rcu_init_percpu_data(), and this function's text
will be discarded after boot when !CONFIG_HOTPLUG_CPU.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

* 'x86-pat-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86 PAT: remove CPA WARN_ON for zero pte
  x86 PAT: return compatible mapping to remap_pfn_range callers
  x86 PAT: change track_pfn_vma_new to take pgprot_t pointer param
  x86 PAT: consolidate old memtype new memtype check into a function
  x86 PAT: remove PFNMAP type on track_pfn_vma_new() error

* master.kernel.org:/home/rmk/linux-2.6-arm:
  TWL4030: fix clk API usage
  [ARM] 5364/1: allow flush_ioremap_region() to be used from modules
  [ARM] w90x900: fix build errors and warnings
  [ARM] i.MX add missing include
  [ARM] i.MX: fix breakage from commit 27889273
  [ARM] i.MX: remove LCDC controller register definitions from imx-regs.h

Since we (Analog Devices) updated our Blackfin kernel to 2.6.28, we've
seen occasional 5-second hangs from telnet.  telnetd calls select with a
NULL timeout, but with the new kernel, the system call occasionally
returns 0, which causes telnet to call sleep (5).  This did not happen
with earlier kernels.

The code in sys_pselect7 looks a bit strange, in particular the variable
"to" is initialized to NULL, then changed if a non-null timeout was
passed in, but not used further.  It needs to be passed to
core_sys_select instead of &end_time.

This bug was introduced by 8ff3e8e8
("select: switch select() and poll() over to hrtimers").
Signed-off-by: Bernd Schmidt <bernd.schmidt@analog.com>
Reviewed-by: Ulrich Drepper <drepper@redhat.com>
Tested-by: Robin Getz <rgetz@blackfin.uclinux.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit b430428a ("8250: Don't clobber
spinlocks.") introduced a regression on the parisc architecture, which
broke the handover to the serial port at boottime.

early_serial_setup() was changed to only copy a subset of the uart_port
fields, and sadly the "type" and "line" fields were forgotten and thus
the serial port was not initialized and could not be used for a
handover.  This patch fixes this by copying the missing fields.

As this change to early_serial_setup() doesn't need an initialized
spinlock in the uart_port struct any longer, we can drop the spinlock
initialization in the superio driver.

Cc: David Daney <ddaney@caviumnetworks.com>
Cc: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Cc: linux-parisc@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Always pass a struct device if one is available; and there's really
no reason for the processor specific stuff in this file if only
people would follow the API usage properly by using the struct device.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Impact: reduce scope of debug check - avoid warnings

The logic to find whether identity map exists or not using
high_memory or max_low_pfn_mapped/max_pfn_mapped are not complete
as the memory withing the range may not be mapped if there is a
unusable hole in e820.

Specifically, on my test system I started seeing these warnings with
tools like hwinfo, acpidump trying to map ACPI region.

[   27.400018] ------------[ cut here ]------------
[   27.400344] WARNING: at /home/venkip/src/linus/linux-2.6/arch/x86/mm/pageattr.c:560 __change_page_attr_set_clr+0xf3/0x8b8()
[   27.400821] Hardware name: X7DB8
[   27.401070] CPA: called for zero pte. vaddr = ffff8800cff6a000 cpa->vaddr = ffff8800cff6a000
[   27.401569] Modules linked in:
[   27.401882] Pid: 4913, comm: dmidecode Not tainted 2.6.28-05716-gfe0bdec6 #586
[   27.402141] Call Trace:
[   27.402488]  [<ffffffff80237c21>] warn_slowpath+0xd3/0x10f
[   27.402749]  [<ffffffff80274ade>] ? find_get_page+0xb3/0xc9
[   27.403028]  [<ffffffff80274a2b>] ? find_get_page+0x0/0xc9
[   27.403333]  [<ffffffff80226425>] __change_page_attr_set_clr+0xf3/0x8b8
[   27.403628]  [<ffffffff8028ec99>] ? __purge_vmap_area_lazy+0x192/0x1a1
[   27.403883]  [<ffffffff8028eb52>] ? __purge_vmap_area_lazy+0x4b/0x1a1
[   27.404172]  [<ffffffff80290268>] ? vm_unmap_aliases+0x1ab/0x1bb
[   27.404512]  [<ffffffff80290105>] ? vm_unmap_aliases+0x48/0x1bb
[   27.404766]  [<ffffffff80226d28>] change_page_attr_set_clr+0x13e/0x2e6
[   27.405026]  [<ffffffff80698fa7>] ? _spin_unlock+0x26/0x2a
[   27.405292]  [<ffffffff80227e6a>] ? reserve_memtype+0x19b/0x4e3
[   27.405590]  [<ffffffff80226ffd>] _set_memory_wb+0x22/0x24
[   27.405844]  [<ffffffff80225d28>] ioremap_change_attr+0x26/0x28
[   27.406097]  [<ffffffff80228355>] reserve_pfn_range+0x1a3/0x235
[   27.406427]  [<ffffffff80228430>] track_pfn_vma_new+0x49/0xb3
[   27.406686]  [<ffffffff80286c46>] remap_pfn_range+0x94/0x32c
[   27.406940]  [<ffffffff8022878d>] ? phys_mem_access_prot_allowed+0xb5/0x1a8
[   27.407209]  [<ffffffff803e9bf4>] mmap_mem+0x75/0x9d
[   27.407523]  [<ffffffff8028b3b4>] mmap_region+0x2cf/0x53e
[   27.407776]  [<ffffffff8028b8cc>] do_mmap_pgoff+0x2a9/0x30d
[   27.408034]  [<ffffffff8020f4a4>] sys_mmap+0x92/0xce
[   27.408339]  [<ffffffff8020b65b>] system_call_fastpath+0x16/0x1b
[   27.408614] ---[ end trace 4b16ad70c09a602d ]---
[   27.408871] dmidecode:4913 reserve_pfn_range ioremap_change_attr failed write-back for cff6a000-cff6b000

This is wih track_pfn_vma_new trying to keep identity map in sync.
The address cff6a000 is the ACPI region according to e820.

[    0.000000] BIOS-provided physical RAM map:
[    0.000000]  BIOS-e820: 0000000000000000 - 000000000009c000 (usable)
[    0.000000]  BIOS-e820: 000000000009c000 - 00000000000a0000 (reserved)
[    0.000000]  BIOS-e820: 00000000000cc000 - 00000000000d0000 (reserved)
[    0.000000]  BIOS-e820: 00000000000e4000 - 0000000000100000 (reserved)
[    0.000000]  BIOS-e820: 0000000000100000 - 00000000cff60000 (usable)
[    0.000000]  BIOS-e820: 00000000cff60000 - 00000000cff69000 (ACPI data)
[    0.000000]  BIOS-e820: 00000000cff69000 - 00000000cff80000 (ACPI NVS)
[    0.000000]  BIOS-e820: 00000000cff80000 - 00000000d0000000 (reserved)
[    0.000000]  BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
[    0.000000]  BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
[    0.000000]  BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
[    0.000000]  BIOS-e820: 00000000ff000000 - 0000000100000000 (reserved)
[    0.000000]  BIOS-e820: 0000000100000000 - 0000000230000000 (usable)

And is not mapped as per init_memory_mapping.

[    0.000000] init_memory_mapping: 0000000000000000-00000000cff60000
[    0.000000] init_memory_mapping: 0000000100000000-0000000230000000

We can add logic to check for this. But, there can also be other holes in
identity map when we have 1GB of aligned reserved space in e820.

This patch handles it by removing the WARN_ON and returning a specific
error value (EFAULT) to indicate that the address does not have any
identity mapping.

The code that tries to keep identity map in sync can ignore
this error, with other callers of cpa still getting error here.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: avoid warning message, potentially solve 3D performance regression

Change x86 PAT code to return compatible memtype if the exact memtype that
was requested in remap_pfn_rage and friends is not available due to some
conflict.

This is done by returning the compatible type in pgprot parameter of
track_pfn_vma_new(), and the caller uses that memtype for page table.

Note that track_pfn_vma_copy() which is basically called during fork gets the
prot from existing page table and should not have any conflict. Hence we use
strict memtype check there and do not allow compatible memtypes.

This patch fixes the bug reported here:

  http://marc.info/?l=linux-kernel&m=123108883716357&w=2

Specifically the error message:

  X:5010 map pfn expected mapping type write-back for d0000000-d0101000,
  got write-combining

Should go away.
Reported-and-bisected-by: Kevin Winchester <kjwinchester@gmail.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: cleanup

Change the protection parameter for track_pfn_vma_new() into a pgprot_t pointer.
Subsequent patch changes the x86 PAT handling to return a compatible
memtype in pgprot_t, if what was requested cannot be allowed due to conflicts.
No fuctionality change in this patch.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: cleanup

Move the new memtype old memtype allowed check to header so that is can be
shared by other users. Subsequent patch uses this in pat.c in remap_pfn_range()
code path. No functionality change in this patch.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Impact: fix (harmless) double-free of memtype entries and avoid warning

On track_pfn_vma_new() failure, reset the vm_flags so that there will be
no second cleanup happening when upper level routines call unmap_vmas().

This patch fixes part of the bug reported here:

  http://marc.info/?l=linux-kernel&m=123108883716357&w=2

Specifically the error message:

  X:5010 freeing invalid memtype d0000000-d0101000

Is due to multiple frees on error path, will not happen with the patch below.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  Revert "i386: add TRACE_IRQS_OFF for the nmi"

Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  smp_call_function_single(): be slightly less stupid, fix #2
  lockdep, mm: fix might_fault() annotation

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband:
  IB/iser: Add dependency on INFINIBAND_ADDR_TRANS
  IPoIB: Do not join broadcast group if interface is brought down
  RDMA/nes: Fix for NIPQUAD removal
  IPoIB: Fix loss of connectivity after bonding failover on both sides
  IB/mlx4: Don't register IB device for adapters with no IB ports
  mlx4_core: Fix warning from min()
  IB/ehca: spin_lock_irqsave() takes an unsigned long

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  pata_it821x: Update RDC UDMA handling
  ata: fix wrong WARN_ON_ONCE

With some broken BIOSs when VT-d is enabled, the data structures are
filled incorrectly. This can cause a NULL pointer dereference in very
early boot.
Signed-off-by: Dirk Hohndel <hohndel@linux.intel.com>
Acked-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The UDMA affliction is apparently specific to revision 0x11. Keeps us in sync
with drivers/ide current.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

This patch fixes a wrong WARN_ON that was triggered by 32bit PIO support:
WARNING: at drivers/ata/libata-sff.c:1017 ata_sff_hsm_move+0x45e/0x750()

__atapi_pio_bytes simply doesnt know enough to decide if there is a bug.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

Fix ib_iser build to depend on INFINIBAND_ADDR_TRANS; if INET=y but
IPV6=n, then the RDMA CM is not built but INFINIBAND_ISER can be
enabled, leading to:

    ERROR: "rdma_destroy_id" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_connect" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_destroy_qp" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_create_id" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_create_qp" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_resolve_route" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_disconnect" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
    ERROR: "rdma_resolve_addr" [drivers/infiniband/ulp/iser/ib_iser.ko] undefined!
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>

Because the ipoib_workqueue is not flushed when ipoib interface is
brought down, ipoib_mcast_join() may trigger a join to the broadcast
group after priv->broadcast was set to NULL (during cleanup).  This
will cause the system to be a member of the broadcast group when
interface is down.  As a side effect, this breaks the optimization of
setting the Q_key only when joining the broadcast group.
Signed-off-by: Yossi Etigin <yosefe@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

At 37000 feet somewhere near Greenland I woke up from a half-sleep with the
realisation that __lowest_in_progress() is buggy. After landing I checked
and there were indeed 2 problems with it; this patch fixes both:
* The order of the list checks was wrong
* The locking was not correct.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There has been some light flamewar on lkml about decoding oopses
in modules (as part of the crashdump flamewar).

Now this isn't rocket science, just the markup_oops.pl script
cheaped out and didn't handle modules. But really; a flamewar
all about that?? What happened to C++ in the kernel or reading
files from inside the kernel?

This patch adds module support to markup_oops.pl; it's not the
most pretty perl but it works for my testcases...
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add the Multi-Tech cellular modem firmware to the TI USB serial driver.
This firmware was extracted from:

ftp://ftp.multitech.com/wireless/wireless_linux.zip

Firmware licence: "all firmware components are redistributable in binary
	form" per support@multitech.com
	Copyright (C) 2005 Multi-Tech Systems, Inc.
Signed-off-by: Chris Adams <cmadams@hiwaay.net>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add Multi-Tech cellular modem support to the ti_usb_3410_5052 driver.
Signed-off-by: Chris Adams <cmadams@hiwaay.net>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The TI USB serial driver supports specifying alternate vendor and
product IDs (since the chips can and are used in devices under other
vendor/product IDs).  However, the alternate IDs were not loaded in the
combined product table.  This patch also adds support for loading
alternate firmware for alternate vendor/product IDs.
Signed-off-by: Chris Adams <cmadams@hiwaay.net>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Julia Lawell found a case where a NULL check was misplaced in the
usb-serial code. However as the object in question cannot be NULL the
check can simply be removed.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Julia Lawall found an un-needed check in the neo driver. Her patch moves
the check to cover the code dereferencing it, however it cannot be NULL
anyway so remove the NULL check instead.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The pty changes and updates for window sizing forgot to correct the
kerneldoc
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  kernel/sched.c: add missing forward declaration for 'double_rq_lock'
  sched: partly revert "sched debug: remove NULL checking in print_cfs_rt_rq()"
  cpumask: fix CONFIG_NUMA=y sched.c

Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sparc64: Fix cpumask related build failure
  smp_call_function_single(): be slightly less stupid, fix
  smp_call_function_single(): be slightly less stupid
  rcu: fix bug in rcutorture system-shutdown code

* 'for-next' of git://git.o-hand.com/linux-mfd:
  mfd: Fix twl4030-core build
  mfd: Ensure sm501 GPIO pin mode is GPIO when configured
  mfd: dm355 evm MMC/SD card detection
  regulator: PCF50633 pmic driver
  input: PCF50633 input driver
  power_supply: PCF50633 battery charger driver
  rtc: PCF50633 rtc driver
  mfd: PCF50633 gpio support
  mfd: PCF50633 adc driver
  mfd: PCF50633 core driver

* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: (37 commits)
  MIPS: Only write c0_framemask on CPUs which have this register.
  MIPS: Alchemy: new userspace suspend interface for development boards.
  MIPS: Alchemy: dbdma suspend/resume support.
  MIPS: Alchemy: Fix up PM code on Au1550/Au1200
  MIPS: Alchemy: move calc_clock function.
  MIPS: Alchemy: RTC counter clocksource / clockevent support.
  MIPS: make cp0 counter clocksource/event usable as fallback.
  MIPS: Alchemy: remove cpu_table.
  MIPS: Alchemy: remove get/set_au1x00_lcd_clock().
  MIPS: Print irq handler description
  MIPS: Alchemy: pb1200: update CPLD cascade irq handler.
  MIPS: Alchemy: update core interrupt code.
  MIPS: Alchemy: move commandline mangling out of common code
  MIPS: Alchemy: devboards: consolidate files
  MIPS: Alchemy: Move development board code to common subdirectory
  MIPS: Add Cavium OCTEON to arch/mips/Kconfig
  MIPS: Add defconfig for Cavium OCTEON.
  MIPS: Adjust the dma-common.c platform hooks.
  MIPS: Add Cavium OCTEON slot into proper tlb category.
  MIPS:  Compute branch returns for Cavium OCTEON specific branch instructions.
  ...