When flushing the AVC, such as during a policy load, the various
network caches are also flushed, with each making a call to
synchronize_net() which has shown to be expensive in some cases.
This patch consolidates the network cache flushes into a single AVC
callback which only calls synchronize_net() once for each AVC cache
flush.
Reported-by: Jaejyn Shin <flagon22bass@gmail.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>

With the introduction of fair queued rwlock, recursive read_lock()
may hang the offending process if there is a write_lock() somewhere
in between.

With recursive read_lock checking enabled, the following error was
reported:

=============================================
[ INFO: possible recursive locking detected ]
3.16.0-rc1 #2 Tainted: G            E
---------------------------------------------
load_policy/708 is trying to acquire lock:
 (policy_rwlock){.+.+..}, at: [<ffffffff8125b32a>]
security_genfs_sid+0x3a/0x170

but task is already holding lock:
 (policy_rwlock){.+.+..}, at: [<ffffffff8125b48c>]
security_fs_use+0x2c/0x110

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(policy_rwlock);
  lock(policy_rwlock);

This patch fixes the occurrence of recursive read_lock() of
policy_rwlock by adding a helper function __security_genfs_sid()
which requires caller to take the lock before calling it. The
security_fs_use() was then modified to call the new helper function.
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <pmoore@redhat.com>

The cond_read_node() should free the given node on error path as it's
not linked to p->cond_list yet.  This is done via cond_node_destroy()
but it's not called when next_entry() fails before the expr loop.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Paul Moore <pmoore@redhat.com>

The node->cur_state and len can be read in a single call of next_entry().
And setting len before reading is a dead write so can be eliminated.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
(Minor tweak to the length parameter in the call to next_entry())
Signed-off-by: Paul Moore <pmoore@redhat.com>

To increase compiler portability there is <linux/compiler.h> which
provides convenience macros for various gcc constructs.  Eg: __packed
for __attribute__((packed)).

This patch is part of a large task I've taken to clean the gcc
specific attributes and use the the macros instead.
Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>

There're some code duplication for reading a string value during
policydb_read().  Add str_read() helper to fix it.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Paul Moore <pmoore@redhat.com>

ARRAY_SIZE is more concise to use when the size of an array is divided
by the size of its type or the size of its first element.

The Coccinelle semantic patch that makes this change is as follows:

// <smpl>
@@
type T;
T[] E;
@@

- (sizeof(E)/sizeof(E[...]))
+ ARRAY_SIZE(E)
// </smpl>
Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>

Files added to hostprogs-y are cleaned. (See scripts/Makefile.clean)
Adding them to clean-files is redundant.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>

Linux 3.15

This reverts commit 3e1a878b.

It came in very late, and already has one reported failure: Sitsofe
reports that the current tree fails to boot on his EeePC, and bisected
it down to this.  Rather than waste time trying to figure out what's
wrong, just revert it.
Reported-by: Sitsofe Wheeler <sitsofe@gmail.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull btrfs fix from Chris Mason:
 "I had this in my 3.16 merge window queue, but it is small and obvious
  enough for 3.15.  I cherry-picked and retested against current rc8"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: send, fix corrupted path strings for long paths

Pull SCSI target fixes from Nicholas Bellinger:
 "Here are the remaining fixes for v3.15.

  This series includes:

   - iser-target fix for ImmediateData exception reference count bug
     (Sagi + nab)
   - iscsi-target fix for MC/S login + potential iser-target MRDSL
     buffer overrun (Santosh + Roland)
   - iser-target fix for v3.15-rc multi network portal shutdown
     regression (nab)
   - target fix for allowing READ_CAPCITY during ALUA Standby access
     state (Chris + nab)
   - target fix for NULL pointer dereference of alua_access_state for
     un-configured devices (Chris + nab)"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  target: Fix alua_access_state attribute OOPs for un-configured devices
  target: Allow READ_CAPACITY opcode in ALUA Standby access state
  iser-target: Fix multi network portal shutdown regression
  iscsi-target: Fix wrong buffer / buffer overrun in iscsi_change_param_value()
  iser-target: Add missing target_put_sess_cmd for ImmedateData failure

Pull x86 fixes from Peter Anvin:
 "A significantly larger than I'd like set of patches for just below the
  wire.  All of these, however, fix real problems.

  The one thing that is genuinely scary in here is the change of SMP
  initialization, but that *does* fix a confirmed hang when booting
  virtual machines.

  There is also a patch to actually do the right thing about not
  offlining a CPU when there are not enough interrupt vectors available
  in the system; the accounting was done incorrectly.  The worst case
  for that patch is that we fail to offline CPUs when we should (the new
  code is strictly more conservative than the old), so is not
  particularly risky.

  Most of the rest is minor stuff; the EFI patches are all about
  exporting correct information to boot loaders and kexec"

* 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: EFI_MIXED should not prohibit loading above 4G
  x86/smpboot: Initialize secondary CPU only if master CPU will wait for it
  x86/smpboot: Log error on secondary CPU wakeup failure at ERR level
  x86: Fix list/memory corruption on CPU hotplug
  x86: irq: Get correct available vectors for cpu disable
  x86/efi: Do not export efi runtime map in case old map
  x86/efi: earlyprintk=efi,keep fix

commit 7d453eee ("x86/efi: Wire up CONFIG_EFI_MIXED") introduced a
regression for the functionality to load kernels above 4G. The relevant
(incorrect) reasoning behind this change can be seen in the commit
message,

  "The xloadflags field in the bzImage header is also updated to reflect
  that the kernel supports both entry points by setting both of
  XLF_EFI_HANDOVER_32 and XLF_EFI_HANDOVER_64 when CONFIG_EFI_MIXED=y.
  XLF_CAN_BE_LOADED_ABOVE_4G is disabled so that the kernel text is
  guaranteed to be addressable with 32-bits."

This is obviously bogus since 32-bit EFI loaders will never place the
kernel above the 4G mark. So this restriction is entirely unnecessary.

But things are worse than that - since we want to encourage people to
always compile with CONFIG_EFI_MIXED=y so that their kernels work out of
the box for both 32-bit and 64-bit firmware, commit 7d453eee
effectively disables XLF_CAN_BE_LOADED_ABOVE_4G completely.

Remove the overzealous and superfluous restriction and restore the
XLF_CAN_BE_LOADED_ABOVE_4G functionality.

Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1402140380-15377-1-git-send-email-matt@console-pimps.orgSigned-off-by: H. Peter Anvin <hpa@zytor.com>

The age table walker doesn't check non-present hugetlb entry in common
path, so hugetlb_entry() callbacks must check it.  The reason for this
behavior is that some callers want to handle it in its own way.

[ I think that reason is bogus, btw - it should just do what the regular
  code does, which is to call the "pte_hole()" function for such hugetlb
  entries  - Linus]

However, some callers don't check it now, which causes unpredictable
result, for example when we have a race between migrating hugepage and
reading /proc/pid/numa_maps.  This patch fixes it by adding !pte_present
checks on buggy callbacks.

This bug exists for years and got visible by introducing hugepage
migration.

ChangeLog v2:
- fix if condition (check !pte_present() instead of pte_present())
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org> [3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Backported to 3.15.  Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org> ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If a path has more than 230 characters, we allocate a new buffer to
use for the path, but we were forgotting to copy the contents of the
previous buffer into the new one, which has random content from the
kmalloc call.

Test:

    mkfs.btrfs -f /dev/sdd
    mount /dev/sdd /mnt

    TEST_PATH="/mnt/fdmanana/.config/google-chrome-mysetup/Default/Pepper_Data/Shockwave_Flash/WritableRoot/#SharedObjects/JSHJ4ZKN/s.wsj.net/[[IMPORT]]/players.edgesuite.net/flash/plugins/osmf/advanced-streaming-plugin/v2.7/osmf1.6/Ak#"
    mkdir -p $TEST_PATH
    echo "hello world" > $TEST_PATH/amaiAdvancedStreamingPlugin.txt

    btrfs subvolume snapshot -r /mnt /mnt/mysnap1
    btrfs send /mnt/mysnap1 -f /tmp/1.snap

A test for xfstests follows.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Cc: Marc Merlin <marc@merlins.org>
Tested-by: Marc MERLIN <marc@merlins.org>
Signed-off-by: Chris Mason <clm@fb.com>

Pull scheduler fixes from Ingo Molnar:
 "Four misc fixes: each was deemed serious enough to warrant v3.15
  inclusion"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix tg_set_cfs_bandwidth() deadlock on rq->lock
  sched/dl: Fix race in dl_task_timer()
  sched: Fix sched_policy < 0 comparison
  sched/numa: Fix use of spin_{un}lock_irq() when interrupts are disabled

While working address sanitizer for kernel I've discovered
use-after-free bug in __put_anon_vma.

For the last anon_vma, anon_vma->root freed before child anon_vma.
Later in anon_vma_free(anon_vma) we are referencing to already freed
anon_vma->root to check rwsem.

This fixes it by freeing the child anon_vma before freeing
anon_vma->root.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.0+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This patch fixes a OOPs where an attempt to write to the per-device
alua_access_state configfs attribute at:

  /sys/kernel/config/target/core/$HBA/$DEV/alua/$TG_PT_GP/alua_access_state

results in an NULL pointer dereference when the backend device has not
yet been configured.

This patch adds an explicit check for DF_CONFIGURED, and fails with
-ENODEV to avoid this case.
Reported-by: Chris Boot <crb@tiger-computing.co.uk>
Reported-by: Philip Gaw <pgaw@darktech.org.uk>
Cc: Chris Boot <crb@tiger-computing.co.uk>
Cc: Philip Gaw <pgaw@darktech.org.uk>
Cc: stable@vger.kernel.org # 3.8+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch allows READ_CAPACITY + SAI_READ_CAPACITY_16 opcode
processing to occur while the associated ALUA group is in Standby
access state.

This is required to avoid host side LUN probe failures during the
initial scan if an ALUA group has already implicitly changed into
Standby access state.

This addresses a bug reported by Chris + Philip using dm-multipath
+ ESX hosts configured with ALUA multipath.
Reported-by: Chris Boot <crb@tiger-computing.co.uk>
Reported-by: Philip Gaw <pgaw@darktech.org.uk>
Cc: Chris Boot <crb@tiger-computing.co.uk>
Cc: Philip Gaw <pgaw@darktech.org.uk>
Cc: Hannes Reinecke <hare@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

 * Fix earlyprintk=efi,keep support by switching to an ioremap() mapping
   of the framebuffer when early_ioremap() is no longer available and
   dropping __init from functions that may be invoked after
   free_initmem() - Dave Young

 * We shouldn't be exporting the EFI runtime map in sysfs if not using
   the new 1:1 EFI mapping code since in that case the mappings are not
   static across a kexec reboot - Dave Young
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Pull perf fixes from Ingo Molnar:
 "Two last minute tooling fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf probe: Fix perf probe to find correct variable DIE
  perf probe: Fix a segfault if asked for variable it doesn't find

Merge futex fixes from Thomas Gleixner:
 "So with more awake and less futex wreckaged brain, I went through my
  list of points again and came up with the following 4 patches.

  1) Prevent pi requeueing on the same futex

     I kept Kees check for uaddr1 == uaddr2 as a early check for private
     futexes and added a key comparison to both futex_requeue and
     futex_wait_requeue_pi.

     Sebastian, sorry for the confusion yesterday night.  I really
     misunderstood your question.

     You are right the check is pointless for shared futexes where the
     same physical address is mapped to two different virtual addresses.

  2) Sanity check atomic acquisiton in futex_lock_pi_atomic

     That's basically what Darren suggested.

     I just simplified it to use futex_top_waiter() to find kernel
     internal state.  If state is found return -EINVAL and do not bother
     to fix up the user space variable.  It's corrupted already.

  3) Ensure state consistency in futex_unlock_pi

     The code is silly versus the owner died bit.  There is no point to
     preserve it on unlock when the user space thread owns the futex.

     What's worse is that it does not update the user space value when
     the owner died bit is set.  So the kernel itself creates observable
     inconsistency.

     Another "optimization" is to retry an atomic unlock.  That's
     pointless as in a sane environment user space would not call into
     that code if it could have unlocked it atomically.  So we always
     check whether there is kernel state around and only if there is
     none, we do the unlock by setting the user space value to 0.

  4) Sanitize lookup_pi_state

     lookup_pi_state is ambigous about TID == 0 in the user space value.

     This can be a valid state even if there is kernel state on this
     uaddr, but we miss a few corner case checks.

     I tried to come up with a smaller solution hacking the checks into
     the current cruft, but it turned out to be ugly as hell and I got
     more confused than I was before.  So I rewrote the sanity checks
     along the state documentation with awful lots of commentry"

* emailed patches from Thomas Gleixner <tglx@linutronix.de>:
  futex: Make lookup_pi_state more robust
  futex: Always cleanup owner tid in unlock_pi
  futex: Validate atomic acquisition in futex_lock_pi_atomic()
  futex-prevent-requeue-pi-on-same-futex.patch futex: Forbid uaddr == uaddr2 in futex_requeue(..., requeue_pi=1)

The current implementation of lookup_pi_state has ambigous handling of
the TID value 0 in the user space futex.  We can get into the kernel
even if the TID value is 0, because either there is a stale waiters bit
or the owner died bit is set or we are called from the requeue_pi path
or from user space just for fun.

The current code avoids an explicit sanity check for pid = 0 in case
that kernel internal state (waiters) are found for the user space
address.  This can lead to state leakage and worse under some
circumstances.

Handle the cases explicit:

       Waiter | pi_state | pi->owner | uTID      | uODIED | ?

  [1]  NULL   | ---      | ---       | 0         | 0/1    | Valid
  [2]  NULL   | ---      | ---       | >0        | 0/1    | Valid

  [3]  Found  | NULL     | --        | Any       | 0/1    | Invalid

  [4]  Found  | Found    | NULL      | 0         | 1      | Valid
  [5]  Found  | Found    | NULL      | >0        | 1      | Invalid

  [6]  Found  | Found    | task      | 0         | 1      | Valid

  [7]  Found  | Found    | NULL      | Any       | 0      | Invalid

  [8]  Found  | Found    | task      | ==taskTID | 0/1    | Valid
  [9]  Found  | Found    | task      | 0         | 0      | Invalid
  [10] Found  | Found    | task      | !=taskTID | 0/1    | Invalid

 [1] Indicates that the kernel can acquire the futex atomically. We
     came came here due to a stale FUTEX_WAITERS/FUTEX_OWNER_DIED bit.

 [2] Valid, if TID does not belong to a kernel thread. If no matching
     thread is found then it indicates that the owner TID has died.

 [3] Invalid. The waiter is queued on a non PI futex

 [4] Valid state after exit_robust_list(), which sets the user space
     value to FUTEX_WAITERS | FUTEX_OWNER_DIED.

 [5] The user space value got manipulated between exit_robust_list()
     and exit_pi_state_list()

 [6] Valid state after exit_pi_state_list() which sets the new owner in
     the pi_state but cannot access the user space value.

 [7] pi_state->owner can only be NULL when the OWNER_DIED bit is set.

 [8] Owner and user space value match

 [9] There is no transient state which sets the user space TID to 0
     except exit_robust_list(), but this is indicated by the
     FUTEX_OWNER_DIED bit. See [4]

[10] There is no transient state which leaves owner and user space
     TID out of sync.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Drewry <wad@chromium.org>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If the owner died bit is set at futex_unlock_pi, we currently do not
cleanup the user space futex.  So the owner TID of the current owner
(the unlocker) persists.  That's observable inconsistant state,
especially when the ownership of the pi state got transferred.

Clean it up unconditionally.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Drewry <wad@chromium.org>
Cc: Darren Hart <dvhart@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We need to protect the atomic acquisition in the kernel against rogue
user space which sets the user space futex to 0, so the kernel side
acquisition succeeds while there is existing state in the kernel
associated to the real owner.

Verify whether the futex has waiters associated with kernel state.  If
it has, return -EINVAL.  The state is corrupted already, so no point in
cleaning it up.  Subsequent calls will fail as well.  Not our problem.

[ tglx: Use futex_top_waiter() and explain why we do not need to try
  	restoring the already corrupted user space state. ]
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Drewry <wad@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

futex-prevent-requeue-pi-on-same-futex.patch futex: Forbid uaddr == uaddr2 in futex_requeue(..., requeue_pi=1)

If uaddr == uaddr2, then we have broken the rule of only requeueing from
a non-pi futex to a pi futex with this call.  If we attempt this, then
dangling pointers may be left for rt_waiter resulting in an exploitable
condition.

This change brings futex_requeue() in line with futex_wait_requeue_pi()
which performs the same check as per commit 6f7b0a2a ("futex: Forbid
uaddr == uaddr2 in futex_wait_requeue_pi()")

[ tglx: Compare the resulting keys as well, as uaddrs might be
  	different depending on the mapping ]

Fixes CVE-2014-3153.

Reported-by: Pinkie Pie
Signed-off-by: Will Drewry <wad@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Hang is observed on virtual machines during CPU hotplug,
especially in big guests with many CPUs. (It reproducible
more often if host is over-committed).

It happens because master CPU gives up waiting on
secondary CPU and allows it to run wild. As result
AP causes locking or crashing system. For example
as described here:

   https://lkml.org/lkml/2014/3/6/257

If master CPU have sent STARTUP IPI successfully,
and AP signalled to master CPU that it's ready
to start initialization, make master CPU wait
indefinitely till AP is onlined.
To ensure that AP won't ever run wild, make it
wait at early startup till master CPU confirms its
intention to wait for AP. If AP doesn't respond in 10
seconds, the master CPU will timeout and cancel
AP onlining.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1401975765-22328-4-git-send-email-imammedo@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

If system is running without debug level logging,
it will not log error if do_boot_cpu() failed to
wakeup AP. It may lead to silent AP bringup
failures at boot time.
Change message level to KERN_ERR to make error
visible to user as it's done on other architectures.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1401975765-22328-3-git-send-email-imammedo@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

currently if AP wake up is failed, master CPU marks AP as not
present in do_boot_cpu() by calling set_cpu_present(cpu, false).
That leads to following list corruption on the next physical CPU
hotplug:

[  418.107336] WARNING: CPU: 1 PID: 45 at lib/list_debug.c:33 __list_add+0xbe/0xd0()
[  418.115268] list_add corruption. prev->next should be next (ffff88003dc57600), but was ffff88003e20c3a0. (prev=ffff88003e20c3a0).
[  418.123693] Modules linked in: nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6t_REJECT ipt_REJECT cfg80211 xt_conntrack rfkill ee
[  418.138979] CPU: 1 PID: 45 Comm: kworker/u10:1 Not tainted 3.14.0-rc6+ #387
[  418.149989] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007
[  418.165750] Workqueue: kacpi_hotplug acpi_hotplug_work_fn
[  418.166433]  0000000000000021 ffff880038ca7988 ffffffff8159b22d 0000000000000021
[  418.176460]  ffff880038ca79d8 ffff880038ca79c8 ffffffff8106942c ffff880038ca79e8
[  418.177453]  ffff88003e20c3a0 ffff88003dc57600 ffff88003e20c3a0 00000000ffffffea
[  418.178445] Call Trace:
[  418.185811]  [<ffffffff8159b22d>] dump_stack+0x49/0x5c
[  418.186440]  [<ffffffff8106942c>] warn_slowpath_common+0x8c/0xc0
[  418.187192]  [<ffffffff81069516>] warn_slowpath_fmt+0x46/0x50
[  418.191231]  [<ffffffff8136ef51>] ? acpi_ns_get_node+0xb7/0xc7
[  418.193889]  [<ffffffff812f796e>] __list_add+0xbe/0xd0
[  418.196649]  [<ffffffff812e2aa9>] kobject_add_internal+0x79/0x200
[  418.208610]  [<ffffffff812e2e18>] kobject_add_varg+0x38/0x60
[  418.213831]  [<ffffffff812e2ef4>] kobject_add+0x44/0x70
[  418.229961]  [<ffffffff813e2c60>] device_add+0xd0/0x550
[  418.234991]  [<ffffffff813f0e95>] ? pm_runtime_init+0xe5/0xf0
[  418.250226]  [<ffffffff813e32be>] device_register+0x1e/0x30
[  418.255296]  [<ffffffff813e82a3>] register_cpu+0xe3/0x130
[  418.266539]  [<ffffffff81592be5>] arch_register_cpu+0x65/0x150
[  418.285845]  [<ffffffff81355c0d>] acpi_processor_hotadd_init+0x5a/0x9b
...
Which is caused by the fact that generic_processor_info() allocates
logical CPU id by calling:

 cpu = cpumask_next_zero(-1, cpu_present_mask);

which returns id of previously failed to wake up CPU, since its
bit is cleared by do_boot_cpu() and as result register_cpu()
tries to register another CPU with the same id as already
present but failed to be onlined CPU.

Taking in account that AP will not do anything if master CPU
failed to wake it up, there is no reason to mark that AP as not
present and break next cpu hotplug attempts. As a side effect of
not marking AP as not present, user would be allowed to online
it again later.

Also fix memory corruption in acpi_unmap_lsapic()

if during CPU hotplug master CPU failed to wake up AP
it set percpu x86_cpu_to_apicid to BAD_APICID=0xFFFF for AP.

However following attempt to unplug that CPU will lead to
out of bound write access to __apicid_to_node[] which is
32768 items long on x86_64 kernel.

So with above fix of cpu_present_mask make sure that a present
CPU has a valid APIC ID by not setting x86_cpu_to_apicid
to BAD_APICID in do_boot_cpu() on failure and allow
acpi_processor_remove()->acpi_unmap_lsapic() cleanly remove CPU.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1401975765-22328-2-git-send-email-imammedo@redhat.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

tg_set_cfs_bandwidth() sets cfs_b->timer_active to 0 to
force the period timer restart. It's not safe, because
can lead to deadlock, described in commit 927b54fc:
"__start_cfs_bandwidth calls hrtimer_cancel while holding rq->lock,
waiting for the hrtimer to finish. However, if sched_cfs_period_timer
runs for another loop iteration, the hrtimer can attempt to take
rq->lock, resulting in deadlock."

Three CPUs must be involved:

  CPU0               CPU1                         CPU2
  take rq->lock      period timer fired
  ...                take cfs_b lock
  ...                ...                          tg_set_cfs_bandwidth()
  throttle_cfs_rq()  release cfs_b lock           take cfs_b lock
  ...                distribute_cfs_runtime()     timer_active = 0
  take cfs_b->lock   wait for rq->lock            ...
  __start_cfs_bandwidth()
  {wait for timer callback
   break if timer_active == 1}

So, CPU0 and CPU1 are deadlocked.

Instead of resetting cfs_b->timer_active, tg_set_cfs_bandwidth can
wait for period timer callbacks (ignoring cfs_b->timer_active) and
restart the timer explicitly.
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/87wqdi9g8e.wl\%klamm@yandex-team.ru
Cc: pjt@google.com
Cc: chris.j.arges@canonical.com
Cc: gregkh@linuxfoundation.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Throttled task is still on rq, and it may be moved to other cpu
if user is playing with sched_setaffinity(). Therefore, unlocked
task_rq() access makes the race.

Juri Lelli reports he got this race when dl_bandwidth_enabled()
was not set.

Other thing, pointed by Peter Zijlstra:

   "Now I suppose the problem can still actually happen when
    you change the root domain and trigger a effective affinity
    change that way".

To fix that we do the same as made in __task_rq_lock(). We do not
use __task_rq_lock() itself, because it has a useful lockdep check,
which is not correct in case of dl_task_timer(). We do not need
pi_lock locked here. This case is an exception (PeterZ):

   "The only reason we don't strictly need ->pi_lock now is because
    we're guaranteed to have p->state == TASK_RUNNING here and are
    thus free of ttwu races".
Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/3056991400578422@web14g.yandex.ruSigned-off-by: Ingo Molnar <mingo@kernel.org>

attr.sched_policy is u32, therefore a comparison against < 0 is never true.
Fix this by casting sched_policy to int.

This issue was reported by coverity CID 1219934.

Fixes: dbdb2275 ("sched: Disallow sched_attr::sched_policy < 0")
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1401741514-7045-1-git-send-email-richard@nod.atSigned-off-by: Ingo Molnar <mingo@kernel.org>

As Peter Zijlstra told me, we have the following path:

do_exit()
  exit_itimers()
    itimer_delete()
      spin_lock_irqsave(&timer->it_lock, &flags);
      timer_delete_hook(timer);
        kc->timer_del(timer) := posix_cpu_timer_del()
          put_task_struct()
            __put_task_struct()
              task_numa_free()
                spin_lock(&grp->lock);

Which means that task_numa_free() can be called with interrupts
disabled, which means that we should not be using spin_lock_irq() but
spin_lock_irqsave() instead. Otherwise we are enabling interrupts while
holding an interrupt unsafe lock!
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner<tglx@linutronix.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140527182541.GH11096@twins.programming.kicks-ass.netSigned-off-by: Ingo Molnar <mingo@kernel.org>

Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf into perf/urgent

Pull perf/urgent fixes from Jiri Olsa:

 * Fix perf probe to find correct variable DIE (Masami Hiramatsu)

 * Fix a segfault in perf probe if asked for variable it doesn't find (Masami Hiramatsu)
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull percpu fix from Tejun Heo:
 "It is very late but this is an important percpu-refcount fix from
  Sebastian Ott.

  The problem is that percpu_ref_*() used __this_cpu_*() instead of
  this_cpu_*().  The difference between the two is that the latter is
  atomic on the local cpu while the former is not.  this_cpu_inc() is
  guaranteed to increment the percpu counter on the cpu that the
  operation is executed on without any synchronization; however,
  __this_cpu_inc() doesn't and if the local cpu invokes the function
  from different contexts (e.g.  process and irq) of the same CPU, it's
  not guaranteed to actually increment as it may be implemented as rmw.

  This bug existed from the get-go but it hasn't been noticed earlier
  probably because on x86 __this_cpu_inc() is equivalent to
  this_cpu_inc() as both get translated into single instruction;
  however, s390 uses the generic rmw implementation and gets affected by
  the bug.  Kudos to Sebastian and Heiko for diagnosing it.

  The change is very low risk and fixes a critical issue on the affected
  architectures, so I think it's a good candidate for inclusion although
  it's very late in the devel cycle.  On the other hand, this has been
  broken since v3.11, so backporting it through -stable post -rc1 won't
  be the end of the world.

  I'll ping Christoph whether __this_cpu_*() ops can be better annotated
  so that it can trigger lockdep warning when used from multiple
  contexts"

* 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu-refcount: fix usage of this_cpu_ops

The percpu-refcount infrastructure uses the underscore variants of
this_cpu_ops in order to modify percpu reference counters.
(e.g. __this_cpu_inc()).

However the underscore variants do not atomically update the percpu
variable, instead they may be implemented using read-modify-write
semantics (more than one instruction).  Therefore it is only safe to
use the underscore variant if the context is always the same (process,
softirq, or hardirq). Otherwise it is possible to lose updates.

This problem is something that Sebastian has seen within the aio
subsystem which uses percpu refcounters both in process and softirq
context leading to reference counts that never dropped to zeroes; even
though the number of "get" and "put" calls matched.

Fix this by using the non-underscore this_cpu_ops variant which
provides correct per cpu atomic semantics and fixes the corrupted
reference counts.

Cc: Kent Overstreet <kmo@daterainc.com>
Cc: <stable@vger.kernel.org> # v3.11+
Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
References: http://lkml.kernel.org/g/alpine.LFD.2.11.1406041540520.21183@denkbrett

Pull intel pstate fixes from Rafael Wysocki:
 "Final power management fixes for 3.15

   - Taking non-idle time into account when calculating core busy time
     was a mistake and led to a performance regression.  Since the
     problem it was supposed to address is now taken care of in a
     different way, we don't need to do it any more, so drop the
     non-idle time tracking from intel_pstate.  Dirk Brandewie.

   - Changing to fixed point math throughout the busy calculation
     introduced rounding errors that adversely affect the accuracy of
     intel_pstate's computations.  Fix from Dirk Brandewie.

   - The PID controller algorithm used by intel_pstate assumes that the
     time interval between two adjacent samples will always be the same
     which is not the case for deferable timers (used by intel_pstate)
     when the system is idle.  This leads to inaccurate predictions and
     artificially increases convergence times for the minimum P-state.
     Fix from Dirk Brandewie.

   - intel_pstate carries out computations using 32-bit variables that
     may overflow for large enough values of APERF/MPERF.  Switch to
     using 64-bit variables for computations, from Doug Smythies"

* tag 'pm-3.15-final' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  intel_pstate: Improve initial busy calculation
  intel_pstate: add sample time scaling
  intel_pstate: Correct rounding in busy calculation
  intel_pstate: Remove C0 tracking

Pull drm fixes from Dave Airlie:
 "All fairly small: radeon stability and a panic path fix.

  Mostly radeon fixes, suspend/resume fix, stability on the CIK
  chipsets, along with a locking check avoidance patch for panic times
  regression"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/radeon: use the CP DMA on CIK
  drm/radeon: sync page table updates
  drm/radeon: fix vm buffer size estimation
  drm/crtc-helper: skip locking checks in panicking path
  drm/radeon/dpm: resume fixes for some systems