Using:
- CONFIG_LOCKUP_DETECTOR=y
- CONFIG_PREEMPT=y
- CONFIG_LOCKDEP=y
- CONFIG_PROVE_LOCKING=y
- CONFIG_PROVE_RCU=y
found a missing rcu lock during boot on a 512 MiB x86_64 ubuntu vm:
  ===================================================
  [ INFO: suspicious rcu_dereference_check() usage. ]
  ---------------------------------------------------
  kernel/pid.c:419 invoked rcu_dereference_check() without protection!

  other info that might help us debug this:

  rcu_scheduler_active = 1, debug_locks = 0
  1 lock held by ureadahead/1355:
   #0:  (tasklist_lock){.+.+..}, at: [<ffffffff8115bc09>] sys_ioprio_set+0x7f/0x29e

  stack backtrace:
  Pid: 1355, comm: ureadahead Not tainted 2.6.37-dbg-DEV #1
  Call Trace:
   [<ffffffff8109c10c>] lockdep_rcu_dereference+0xaa/0xb3
   [<ffffffff81088cbf>] find_task_by_pid_ns+0x44/0x5d
   [<ffffffff81088cfa>] find_task_by_vpid+0x22/0x24
   [<ffffffff8115bc3e>] sys_ioprio_set+0xb4/0x29e
   [<ffffffff8147cf21>] ? trace_hardirqs_off_thunk+0x3a/0x3c
   [<ffffffff8105c409>] sysenter_dispatch+0x7/0x2c
   [<ffffffff8147cee2>] ? trace_hardirqs_on_thunk+0x3a/0x3f

The fix is to:
a) grab rcu lock in sys_ioprio_{set,get}() and
b) avoid grabbing tasklist_lock.
Discussion in: http://marc.info/?l=linux-kernel&m=128951324702889Signed-off-by: NGreg Thelen <gthelen@google.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>

Modified by Jens to remove the now redundant inner rcu lock and
unlock since they are now protected by the outer lock.
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Merge branch 'upstream/blkfront' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen into for-linus

Conflicts:
	drivers/block/xen-blkfront.c
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Reported-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Remove anticipatory block I/O scheduler info from Documentation/
since the code has been deleted.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Reported-by: N"Robert P. J. Day" <rpjday@crashcourse.ca>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

REQ_HARDBARRIER is dead now, so remove the leftovers.  What's left
at this point is:

 - various checks inside the block layer.
 - sanity checks in bio based drivers.
 - now unused bio_empty_barrier helper.
 - Xen blockfront use of BLKIF_OP_WRITE_BARRIER - it's dead for a while,
   but Xen really needs to sort out it's barrier situaton.
 - setting of ordered tags in uas - dead code copied from old scsi
   drivers.
 - scsi different retry for barriers - it's dead and should have been
   removed when flushes were converted to FS requests.
 - blktrace handling of barriers - removed.  Someone who knows blktrace
   better should add support for REQ_FLUSH and REQ_FUA, though.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Conflicts:
	drivers/block/cciss.c
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Commit 4221a991 "Add RCU check for
find_task_by_vpid()" introduced rcu_lockdep_assert to find_task_by_pid_ns=

Assertion failed in sys_ioprio_get. The patch is fixing assertion
failure in ioprio_set as well.

 kernel/pid.c:419 invoked rcu_dereference_check() without protection!

 stack backtrace:
 Pid: 4254, comm: iotop Not tainted
 Call Trace:
 [<ffffffff810656f2>] lockdep_rcu_dereference+0xaa/0xb2
 [<ffffffff81053c67>] find_task_by_pid_ns+0x4f/0x68
 [<ffffffff81053c9d>] find_task_by_vpid+0x1d/0x1f
 [<ffffffff811104e2>] sys_ioprio_get+0x50/0x2da
 [<ffffffff81002182>] system_call_fastpath+0x16/0x1b

V2: rcu critical section expanded according to comment by Paul E. McKenney
Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

With 2.6.37-rc1, I observe sys_ioprio_set not taking the RCU lock [1]
across access to the task credentials.

Inspecting the code in fs/ioprio.c, the tasklist_lock is held for read
across the __task_cred call, which is presumably sufficient to prevent
the task credentials becoming stale.

===================================================

[ INFO: suspicious rcu_dereference_check() usage. ]

---------------------------------------------------

kernel/pid.c:419 invoked rcu_dereference_check() without protection!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 1

1 lock held by start-stop-daem/2246:

 #0:  (tasklist_lock){.?.?..}, at: [<ffffffff811a2dfa>]
sys_ioprio_set+0x8a/0x400

stack backtrace:

Pid: 2246, comm: start-stop-daem Not tainted 2.6.37-rc1-330cd+ #2

Call Trace:

 [<ffffffff8109f5f4>] lockdep_rcu_dereference+0xa4/0xc0

 [<ffffffff81085651>] find_task_by_pid_ns+0x81/0x90

 [<ffffffff8108567d>] find_task_by_vpid+0x1d/0x20

 [<ffffffff811a3160>] sys_ioprio_set+0x3f0/0x400

 [<ffffffff816efa79>] ? trace_hardirqs_on_thunk+0x3a/0x3f

 [<ffffffff81003482>] system_call_fastpath+0x16/0x1b

Take the RCU lock for read across acquiring the pointer to the task
credentials and dereferencing it.
Signed-off-by: NDaniel J Blueman <daniel.blueman@gmail.com>

Fixed up by Jens to fix missing rcu_read_unlock() on mismatches.
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Structure hd_geometry is copied to userland with 4 padding bytes
between cylinders and start fields uninitialized on 64-bit platforms.
It leads to leaking of contents of kernel stack memory.

Currently there is no memset() in real implementations of getgeo()
in drivers/block/, so it makes sense to have memset() in blkdev_ioctl().
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Convert direct reads of an inode's i_size to using i_size_read().

i_size_{read,write} use a seqcount to protect reads from accessing
incomple writes.  Concurrent i_size_write()s require mutual exclussion
to protect the seqcount that is used by i_size_{read,write}.  But
i_size_read() callers do not need to use additional locking.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Acked-by: NNeilBrown <neilb@suse.de>
Acked-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Randy reports that he gets the following stack trace when
removing the cciss module:

[  109.164277] Pid: 3463, comm: rmmod Not tainted 2.6.37-rc1 #7
[  109.164280] Call Trace:
[  109.164292]  [<ffffffff8107eb8d>] warn_slowpath_common+0xc6/0xf3
[  109.164299]  [<ffffffff8107ecaa>] warn_slowpath_fmt+0x5b/0x6b
[  109.164307]  [<ffffffff8155175b>] ? _raw_spin_unlock+0x40/0x4b
[  109.164313]  [<ffffffff8123dd1e>] remove_proc_entry+0x156/0x35e
[  109.164320]  [<ffffffff812cd91b>] ? do_raw_spin_unlock+0xff/0x10f
[  109.164327]  [<ffffffff8113823d>] ? trace_hardirqs_on+0x10/0x4a
[  109.164333]  [<ffffffff8155162d>] ? _raw_spin_unlock_irq+0x4c/0x7b
[  109.164339]  [<ffffffff8154d4d1>] ? wait_for_common+0x145/0x15e
[  109.164345]  [<ffffffff81075337>] ? default_wake_function+0x0/0x22
[  109.164357]  [<ffffffffa0615a8f>] cciss_cleanup+0xa9/0xc7 [cciss]
[  109.164365]  [<ffffffff810d3cb0>] sys_delete_module+0x2d6/0x368
[  109.164371]  [<ffffffff8155036b>] ? lockdep_sys_exit_thunk+0x35/0x67
[  109.164377]  [<ffffffff810fdfaf>] ? audit_syscall_entry+0x172/0x1a5
[  109.164383]  [<ffffffff815502f5>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[  109.164389]  [<ffffffff8100ea72>] system_call_fastpath+0x16/0x1b
[  109.164394] ---[ end trace 88e8568246ed0b1d ]---

which will happen if you don't actually have an HP CISS adapter,
since it'll do an uncondional removal of a proc directory it
never attempted to create in that case.
Reported-by: NRandy Dunlap <randy.dunlap@oracle.com>
Tested-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

If the iovec is being set up in a way that causes uaddr + PAGE_SIZE
to overflow, we could end up attempting to map a huge number of
pages. Check for this invalid input type.
Reported-by: NDan Rosenberg <drosenberg@vsecurity.com>
Cc: stable@kernel.org
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Reported-by: NDan Rosenberg <drosenberg@vsecurity.com>
Cc: stable@kernel.org
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Reported-by: NDan Rosenberg <drosenberg@vsecurity.com>
Cc: stable@kernel.org
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Ensure that we pass down properly validated iov segments before
calling into the mapping or copy functions.
Reported-by: NDan Rosenberg <drosenberg@vsecurity.com>
Cc: stable@kernel.org
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Commit 27ae60f8 ("ipw2x00: replace "ieee80211" with "libipw" where
appropriate") changed DRV_NAME to be "libipw", but didn't properly fix
up the places where it was used to specify the name for the /proc/net/
directory.

For backwards compatibility reasons, that directory name remained
"ieee80211", but due to the DRV_NAME change, the error case printouts
and the cleanup functions now used "libipw" instead.  Which made it all
fail badly.

For example, on module unload as reported by Randy:

  WARNING: at fs/proc/generic.c:816 remove_proc_entry+0x156/0x35e()
  name 'libipw'

because it's trying to unregister a /proc directory that obviously
doesn't even exist.

Clean it all up to use DRV_PROCNAME for the actual /proc directory name.
Reported-and-tested-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Pavel Roskin <proski@gnu.org>
Cc: John W. Linville <linville@tuxdriver.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'kvm-updates/2.6.37' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: PPC: BookE: Load the lower half of MSR
  KVM: PPC: BookE: fix sleep with interrupts disabled
  KVM: PPC: e500: Call kvm_vcpu_uninit() before kvmppc_e500_tlb_uninit().
  PPC: KVM: Book E doesn't have __end_interrupts.
  KVM: x86: Issue smp_call_function_many with preemption disabled
  KVM: x86: fix information leak to userland
  KVM: PPC: fix information leak to userland
  KVM: MMU: fix rmap_remove on non present sptes
  KVM: Write protect memory after slot swap

Commit 48821184 ("floppy: switch to one queue per drive instead of
sharing a queue") introduced a use-after-free.  We do "put_disk()" on
the disk device _before_ we then clean up the queue associated with that
disk.

Move the put_disk() down to avoid dereferencing a free'd data structure.

Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Reported-and-tested-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit d9ca07a0 ("watchdog: Avoid kernel crash when disabling
watchdog") introduces a section mismatch.

Now that we reference no_watchdog from non-__init code it can no longer
be __initdata.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (41 commits)
  inet_diag: Make sure we actually run the same bytecode we audited.
  netlink: Make nlmsg_find_attr take a const nlmsghdr*.
  fib: fib_result_assign() should not change fib refcounts
  netfilter: ip6_tables: fix information leak to userspace
  cls_cgroup: Fix crash on module unload
  memory corruption in X.25 facilities parsing
  net dst: fix percpu_counter list corruption and poison overwritten
  rds: Remove kfreed tcp conn from list
  rds: Lost locking in loop connection freeing
  de2104x: fix panic on load
  atl1 : fix panic on load
  netxen: remove unused firmware exports
  caif: Remove noisy printout when disconnecting caif socket
  caif: SPI-driver bugfix - incorrect padding.
  caif: Bugfix for socket priority, bindtodev and dbg channel.
  smsc911x: Set Ethernet EEPROM size to supported device's size
  ipv4: netfilter: ip_tables: fix information leak to userland
  ipv4: netfilter: arp_tables: fix information leak to userland
  cxgb4vf: remove call to stop TX queues at load time.
  cxgb4: remove call to stop TX queues at load time.
  ...

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
  firewire: ohci: fix race when reading count in AR descriptor
  firewire: ohci: avoid reallocation of AR buffers
  firewire: ohci: fix race in AR split packet handling
  firewire: ohci: fix buffer overflow in AR split packet handling

* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  cifs: make cifs_set_oplock_level() take a cifsInodeInfo pointer
  cifs: dereferencing first then checking
  cifs: trivial comment fix: tlink_tree is now a rbtree
  [CIFS] Cleanup unused variable build warning
  cifs: convert tlink_tree to a rbtree
  cifs: store pointer to master tlink in superblock (try #2)
  cifs: trivial doc fix: note setlease implemented
  CIFS: Add cifs_set_oplock_level
  FS: cifs, remove unneeded NULL tests

posix-cpu-timers.c correctly assumes that the dying process does
posix_cpu_timers_exit_group() and removes all !CPUCLOCK_PERTHREAD
timers from signal->cpu_timers list.

But, it also assumes that timer->it.cpu.task is always the group
leader, and thus the dead ->task means the dead thread group.

This is obviously not true after de_thread() changes the leader.
After that almost every posix_cpu_timer_ method has problems.

It is not simple to fix this bug correctly. First of all, I think
that timer->it.cpu should use struct pid instead of task_struct.
Also, the locking should be reworked completely. In particular,
tasklist_lock should not be used at all. This all needs a lot of
nontrivial and hard-to-test changes.

Change __exit_signal() to do posix_cpu_timers_exit_group() when
the old leader dies during exec. This is not the fix, just the
temporary hack to hide the problem for 2.6.37 and stable. IOW,
this is obviously wrong but this is what we currently have anyway:
cpu timers do not work after mt exec.

In theory this change adds another race. The exiting leader can
detach the timers which were attached to the new leader. However,
the window between de_thread() and release_task() is small, we
can pretend that sys_timer_create() was called before de_thread().
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging:
  hwmon: (ltc4261) Fix error message format
  hwmon: (ltc4261) Add missing newline in debug message

All the callers already have a pointer to struct cifsInodeInfo. Use it.
Signed-off-by: NSuresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: NPavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

adapter->id is deprecated and not set by any adapter driver, so this
was certainly not what the author wanted to use. adapter->nr maybe,
but as dev_err() already includes this value, as well as the client's
address, there's no point repeating them. Better print a simple error
message in plain English words.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: NGuenter Roeck <guenter.roeck@ericsson.com>

Reported-by: NJoe Perches <joe@perches.com>
Signed-off-by: NGuenter Roeck <guenter.roeck@ericsson.com>
Acked-by: NJean Delvare <khali@linux-fr.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  arch/tile: mark "hardwall" device as non-seekable
  asm-generic/stat.h: support 64-bit file time_t for stat()
  arch/tile: don't allow user code to set the PL via ptrace or signal return
  arch/tile: correct double syscall restart for nested signals
  arch/tile: avoid __must_check warning on one strict_strtol check
  arch/tile: bomb raw_local_irq_ to arch_local_irq_
  arch/tile: complete migration to new kmap_atomic scheme

Add MODULE_LICENSE() that matches file comments so that kernel
is not tainted.

	leds_net5501: module license 'unspecified' taints kernel.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Acked-by: NRichard Purdie <rpurdie@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This was preventing the guest from setting any bits in the
hardware MSR which aren't forced on, such as MSR[SPE].
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

It is not legal to call mutex_lock() with interrupts disabled.
This will assert with debug checks enabled.

If there's a real need to disable interrupts here, it could be done
after the mutex is acquired -- but I don't see why it's needed at all.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Reviewed-by: NChristian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

The VCPU uninit calls some TLB functions, and the TLB uninit function
frees the memory used by them.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Acked-by: NLiu Yu <yu.liu@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Fix an unresolved symbol with CONFIG_KVM_GUEST plus CONFIG_RELOCATABLE on
Book E.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

smp_call_function_many is specified to be called only with preemption
disabled. Fulfill this requirement.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Structures kvm_vcpu_events, kvm_debugregs, kvm_pit_state2 and
kvm_clock_data are copied to userland with some padding and reserved
fields unitialized.  It leads to leaking of contents of kernel stack
memory.  We have to initialize them to zero.

In patch v1 Jan Kiszka suggested to fill reserved fields with zeros
instead of memset'ting the whole struct.  It makes sense as these
fields are explicitly marked as padding.  No more fields need zeroing.

KVM-Stable-Tag.
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Structure kvm_ppc_pvinfo is copied to userland with flags and
pad fields unitialized.  It leads to leaking of contents of
kernel stack memory.
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

drop_spte should not attempt to rmap_remove a non present shadow pte.

This fixes a BUG_ON seen on kvm-autotest.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Reported-by: NLucas Meneghel Rodrigues <lmr@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

I have observed the following bug trigger:

1. userspace calls GET_DIRTY_LOG
2. kvm_mmu_slot_remove_write_access is called and makes a page ro
3. page fault happens and makes the page writeable
   fault is logged in the bitmap appropriately
4. kvm_vm_ioctl_get_dirty_log swaps slot pointers

a lot of time passes

5. guest writes into the page
6. userspace calls GET_DIRTY_LOG

At point (5), bitmap is clean and page is writeable,
thus, guest modification of memory is not logged
and GET_DIRTY_LOG returns an empty bitmap.

The rule is that all pages are either dirty in the current bitmap,
or write-protected, which is violated here.

It seems that just moving kvm_mmu_slot_remove_write_access down
to after the slot pointer swap should fix this bug.

KVM-Stable-Tag.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

We can optimize kernel/relay.c::relay_alloc_page_array() slightly by
using vzalloc.  The patch makes these changes:

 - use vzalloc instead of vmalloc+memset.
 - remove redundant local variable 'array'.
 - declare local 'pa_size' as const.

Cuts down nicely on both source and object-code size.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Acked-by: NPekka Enberg <penberg@kernel.org>
Acked-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'for-linus-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
  m68k, m68knommu: Do not include linux/hardirq.h in asm/irqflags.h
  m68knommu: add back in declaration of do_IRQ