audit_add_tree_rule() must set 'rule->tree = NULL;' firstly, to protect
the rule itself freed in kill_rules().

The reason is when it is killed, the 'rule' itself may have already
released, we should not access it.  one example: we add a rule to an
inode, just at the same time the other task is deleting this inode.

The work flow for adding a rule:

    audit_receive() -> (need audit_cmd_mutex lock)
      audit_receive_skb() ->
        audit_receive_msg() ->
          audit_receive_filter() ->
            audit_add_rule() ->
              audit_add_tree_rule() -> (need audit_filter_mutex lock)
                ...
                unlock audit_filter_mutex
                get_tree()
                ...
                iterate_mounts() -> (iterate all related inodes)
                  tag_mount() ->
                    tag_trunk() ->
                      create_trunk() -> (assume it is 1st rule)
                        fsnotify_add_mark() ->
                          fsnotify_add_inode_mark() ->  (add mark to inode->i_fsnotify_marks)
                        ...
                        get_tree(); (each inode will get one)
                ...
                lock audit_filter_mutex

The work flow for deleting an inode:

    __destroy_inode() ->
     fsnotify_inode_delete() ->
       __fsnotify_inode_delete() ->
        fsnotify_clear_marks_by_inode() ->  (get mark from inode->i_fsnotify_marks)
          fsnotify_destroy_mark() ->
           fsnotify_destroy_mark_locked() ->
             audit_tree_freeing_mark() ->
               evict_chunk() ->
                 ...
                 tree->goner = 1
                 ...
                 kill_rules() ->   (assume current->audit_context == NULL)
                   call_rcu() ->   (rule->tree != NULL)
                     audit_free_rule_rcu() ->
                       audit_free_rule()
                 ...
                 audit_schedule_prune() ->  (assume current->audit_context == NULL)
                   kthread_run() ->    (need audit_cmd_mutex and audit_filter_mutex lock)
                     prune_one() ->    (delete it from prue_list)
                       put_tree(); (match the original get_tree above)
Signed-off-by: NChen Gang <gang.chen@asianux.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we have a page fault for the address which is backed by a hugepage
under migration, the kernel can't wait correctly and do busy looping on
hugepage fault until the migration finishes.  As a result, users who try
to kick hugepage migration (via soft offlining, for example) occasionally
experience long delay or soft lockup.

This is because pte_offset_map_lock() can't get a correct migration entry
or a correct page table lock for hugepage.  This patch introduces
migration_entry_wait_huge() to solve this.
Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: NRik van Riel <riel@redhat.com>
Reviewed-by: NWanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: NMichal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@vger.kernel.org>	[2.6.35+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

dlm_mig_lockres_handler() is missing a dlm_lockres_put() on an error path.
Signed-off-by: Njoyce <xuejiufei@huawei.com>
Reviewed-by: Nshencanquan <shencanquan@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The watermark check consists of two sub-checks.  The first one is:

	if (free_pages <= min + lowmem_reserve)
		return false;

The check assures that there is minimal amount of RAM in the zone.  If
CMA is used then the free_pages is reduced by the number of free pages
in CMA prior to the over-mentioned check.

	if (!(alloc_flags & ALLOC_CMA))
		free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);

This prevents the zone from being drained from pages available for
non-movable allocations.

The second check prevents the zone from getting too fragmented.

	for (o = 0; o < order; o++) {
		free_pages -= z->free_area[o].nr_free << o;
		min >>= 1;
		if (free_pages <= min)
			return false;
	}

The field z->free_area[o].nr_free is equal to the number of free pages
including free CMA pages.  Therefore the CMA pages are subtracted twice.
This may cause a false positive fail of __zone_watermark_ok() if the CMA
area gets strongly fragmented.  In such a case there are many 0-order
free pages located in CMA.  Those pages are subtracted twice therefore
they will quickly drain free_pages during the check against
fragmentation.  The test fails even though there are many free non-cma
pages in the zone.

This patch fixes this issue by subtracting CMA pages only for a purpose of
(free_pages <= min + lowmem_reserve) check.

Laura said:

  We were observing allocation failures of higher order pages (order 5 =
  128K typically) under tight memory conditions resulting in driver
  failure.  The output from the page allocation failure showed plenty of
  free pages of the appropriate order/type/zone and mostly CMA pages in
  the lower orders.

  For full disclosure, we still observed some page allocation failures
  even after applying the patch but the number was drastically reduced and
  those failures were attributed to fragmentation/other system issues.
Signed-off-by: NTomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Tested-by: NLaura Abbott <lauraa@codeaurora.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Tested-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Cc: <stable@vger.kernel.org>	[3.7+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The "info.fill" array isn't initialized so it can leak uninitialized stack
information to user space.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NRobin Holt <holt@sgi.com>
Acked-by: NDimitri Sivanich <sivanich@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There was a regression introduced by 36f55889 ("aio: refcounting
cleanup"), reported by Jens Axboe - the refcounting cleanup switched to
using RCU in the shutdown path, but the synchronize_rcu() was done in
the context of the io_destroy() syscall greatly increasing the time it
could block.

This patch switches it to call_rcu() and makes shutdown asynchronous
(more asynchronous than it was originally; before the refcount changes
io_destroy() would still wait on pending kiocbs).

Note that there's a global quota on the max outstanding kiocbs, and that
quota must be manipulated synchronously; otherwise io_setup() could
return -EAGAIN when there isn't quota available, and userspace won't
have any way of waiting until shutdown of the old kioctxs has finished
(besides busy looping).

So we release our quota before kioctx shutdown has finished, which
should be fine since the quota never corresponded to anything real
anyways.
Signed-off-by: NKent Overstreet <koverstreet@google.com>
Cc: Zach Brown <zab@redhat.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Reported-by: NJens Axboe <axboe@kernel.dk>
Tested-by: NJens Axboe <axboe@kernel.dk>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>
Tested-by: NBenjamin LaHaise <bcrl@kvack.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add support for the at91sam9x5-family which must use the shadow
interrupt mask due to a hardware issue (causing RTC_IMR to always be
zero).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: Robert Nelson <Robert.Nelson@digikey.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add shadow interrupt-mask register which can be used on SoCs where the
actual hardware register is broken.

Note that some care needs to be taken to make sure the shadow mask
corresponds to the actual hardware state.  The added overhead is not an
issue for the non-broken SoCs due to the relatively infrequent
interrupt-mask updates.  We do, however, only use the shadow mask value
as a fall-back when it actually needed as there is still a theoretical
possibility that the mask is incorrect (see the code for details).
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: Robert Nelson <Robert.Nelson@digikey.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add accessors for the interrupt register.

This will allow us to easily add a shadow interrupt-mask register to use
on SoCs where the interrupt-mask register cannot be used.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: Robert Nelson <Robert.Nelson@digikey.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add configuration support which can be used to implement SoC-specific
workarounds for broken hardware.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: Robert Nelson <Robert.Nelson@digikey.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The members of Atmel's at91sam9x5 family (9x5) have a broken RTC
interrupt mask register (AT91_RTC_IMR).  It does not reflect enabled
interrupts but instead always returns zero.

The kernel's rtc-at91rm9200 driver handles the RTC for the 9x5 family.
Currently when the date/time is set, an interrupt is generated and this
driver neglects to handle the interrupt.  The kernel complains about the
un-handled interrupt and disables it henceforth.  This not only breaks
the RTC function, but since that interrupt is shared (Atmel's SYS
interrupt) then other things break as well (e.g.  the debug port no
longer accepts characters).

Tested on the at91sam9g25.  Bug confirmed by Atmel.

This patch (of 5):

Add missing match-table compile guard.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: Robert Nelson <Robert.Nelson@digikey.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

While removing a non-empty directory, the kernel dumps a message:

  (rmdir,21743,1):ocfs2_unlink:953 ERROR: status = -39

Suppress the error message from being printed in the dmesg so users
don't panic.
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Acked-by: NSunil Mushran <sunil.mushran@gmail.com>
Reviewed-by: NJie Liu <jeff.liu@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

read_swap_cache_async() can race against get_swap_page(), and stumble
across a SWAP_HAS_CACHE entry in the swap map whose page wasn't brought
into the swapcache yet.

This transient swap_map state is expected to be transitory, but the
actual placement of discard at scan_swap_map() inserts a wait for I/O
completion thus making the thread at read_swap_cache_async() to loop
around its -EEXIST case, while the other end at get_swap_page() is
scheduled away at scan_swap_map().  This can leave the system deadlocked
if the I/O completion happens to be waiting on the CPU waitqueue where
read_swap_cache_async() is busy looping and !CONFIG_PREEMPT.

This patch introduces a cond_resched() call to make the aforementioned
read_swap_cache_async() busy loop condition to bail out when necessary,
thus avoiding the subtle race window.
Signed-off-by: NRafael Aquini <aquini@redhat.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NHugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When booted in legacy mode device_init_wakeup() gets called by
drivers/mfd/twl-core.c when the children are initialized.  However, when
booted using device tree, the children are created with
of_platform_populate() instead add_children().

This means that the RTC driver will not have device_init_wakeup() set,
and we need to call it from the driver probe like RTC drivers typically
do.

Without this we cannot test PM wake-up events on omaps for cases where
there may not be any physical wake-up event.
Signed-off-by: NTony Lindgren <tony@atomide.com>
Reported-by: NKevin Hilman <khilman@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If a new logical drive is added and the CCISS_REGNEWD ioctl is invoked
(as is normal with the Array Configuration Utility) the process will
hang as below.  It attempts to acquire the same mutex twice, once in
do_ioctl() and once in cciss_unlocked_open().  The BKL was recursive,
the mutex isn't.

  Linux version 3.10.0-rc2 (scameron@localhost.localdomain) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-3) (GCC) ) #1 SMP Fri May 24 14:32:12 CDT 2013
  [...]
  acu             D 0000000000000001     0  3246   3191 0x00000080
  Call Trace:
    schedule+0x29/0x70
    schedule_preempt_disabled+0xe/0x10
    __mutex_lock_slowpath+0x17b/0x220
    mutex_lock+0x2b/0x50
    cciss_unlocked_open+0x2f/0x110 [cciss]
    __blkdev_get+0xd3/0x470
    blkdev_get+0x5c/0x1e0
    register_disk+0x182/0x1a0
    add_disk+0x17c/0x310
    cciss_add_disk+0x13a/0x170 [cciss]
    cciss_update_drive_info+0x39b/0x480 [cciss]
    rebuild_lun_table+0x258/0x370 [cciss]
    cciss_ioctl+0x34f/0x470 [cciss]
    do_ioctl+0x49/0x70 [cciss]
    __blkdev_driver_ioctl+0x28/0x30
    blkdev_ioctl+0x200/0x7b0
    block_ioctl+0x3c/0x40
    do_vfs_ioctl+0x89/0x350
    SyS_ioctl+0xa1/0xb0
    system_call_fastpath+0x16/0x1b

This mutex usage was added into the ioctl path when the big kernel lock
was removed.  As it turns out, these paths are all thread safe anyway
(or can easily be made so) and we don't want ioctl() to be single
threaded in any case.
Signed-off-by: NStephen M. Cameron <scameron@beardog.cce.hp.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mike Miller <mike.miller@hp.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

audit_log_start() does wait_for_auditd() in a loop until
audit_backlog_wait_time passes or audit_skb_queue has a room.

If signal_pending() is true this becomes a busy-wait loop, schedule() in
TASK_INTERRUPTIBLE won't block.

Thanks to Guy for fully investigating and explaining the problem.

(akpm: that'll cause the system to lock up on a non-preemptible
uniprocessor kernel)

(Guy: "Our customer was in fact running a uniprocessor machine, and they
reported a system hang.")
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Reported-by: NGuy Streeter <streeter@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

During resume, we call hpet_rtc_timer_init after masking an irq bit in
hpet.  This will cause the call to hpet_disable_rtc_channel to be undone
if RTC_AIE is the only bit not masked.

Allowing the cmos interrupt handler to run before resuming caused some
issues where the timer for the alarm was not removed.  This would cause
other, later timers to not be cleared, so utilities such as hwclock
would time out when waiting for the update interrupt.

[akpm@linux-foundation.org: coding-style tweak]
Signed-off-by: NDerek Basehore <dbasehore@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use device_init_wakeup() instead of device_set_wakeup_capable() and move
it before rtc dev registering.  This fixes alarmtimer not registered
when tps6586x rtc is the only wakeup compatible rtc in the system.
Signed-off-by: NDmitry Osipenko <digetx@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

struct memcg_cache_params has a union.  Different parts of this union
are used for root and non-root caches.  A part with destroying work is
used only for non-root caches.

  BUG: unable to handle kernel paging request at 0000000fffffffe0
  IP: kmem_cache_alloc+0x41/0x1f0
  Modules linked in: netlink_diag af_packet_diag udp_diag tcp_diag inet_diag unix_diag ip6table_filter ip6_tables i2c_piix4 virtio_net virtio_balloon microcode i2c_core pcspkr floppy
  CPU: 0 PID: 1929 Comm: lt-vzctl Tainted: G      D      3.10.0-rc1+ #2
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  RIP: kmem_cache_alloc+0x41/0x1f0
  Call Trace:
   getname_flags.part.34+0x30/0x140
   getname+0x38/0x60
   do_sys_open+0xc5/0x1e0
   SyS_open+0x22/0x30
   system_call_fastpath+0x16/0x1b
  Code: f4 53 48 83 ec 18 8b 05 8e 53 b7 00 4c 8b 4d 08 21 f0 a8 10 74 0d 4c 89 4d c0 e8 1b 76 4a 00 4c 8b 4d c0 e9 92 00 00 00 4d 89 f5 <4d> 8b 45 00 65 4c 03 04 25 48 cd 00 00 49 8b 50 08 4d 8b 38 49
  RIP  [<ffffffff8116b641>] kmem_cache_alloc+0x41/0x1f0
Signed-off-by: NAndrey Vagin <avagin@openvz.org>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: NMichal Hocko <mhocko@suse.cz>
Cc: Li Zefan <lizefan@huawei.com>
Cc: <stable@vger.kernel.org>	[3.9.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If an error occurs, for example an EIO in __ocfs2_prepare_orphan_dir,
ocfs2_prep_new_orphaned_file will release the inode_ac, then when the
caller of ocfs2_prep_new_orphaned_file gets a 0 return, it will refer to
a NULL ocfs2_alloc_context struct in the following functions.  A kernel
panic happens.
Signed-off-by: N"Xiaowei.Hu" <xiaowei.hu@oracle.com>
Reviewed-by: Nshencanquan <shencanquan@huawei.com>
Acked-by: NSunil Mushran <sunil.mushran@gmail.com>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For 'while' looping, need stop when 'nbytes == 0', or will cause issue.
('nbytes' is size_t which is always bigger or equal than zero).

The related warning: (with EXTRA_CFLAGS=-W)

  lib/mpi/mpicoder.c:40:2: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
Signed-off-by: NChen Gang <gang.chen@asianux.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: David Howells <dhowells@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The dmesg_restrict sysctl currently covers the syslog method for access
dmesg, however /dev/kmsg isn't covered by the same protections.  Most
people haven't noticed because util-linux dmesg(1) defaults to using the
syslog method for access in older versions.  With util-linux dmesg(1)
defaults to reading directly from /dev/kmsg.

To fix /dev/kmsg, let's compare the existing interfaces and what they
allow:

 - /proc/kmsg allows:
  - open (SYSLOG_ACTION_OPEN) if CAP_SYSLOG since it uses a destructive
    single-reader interface (SYSLOG_ACTION_READ).
  - everything, after an open.

 - syslog syscall allows:
  - anything, if CAP_SYSLOG.
  - SYSLOG_ACTION_READ_ALL and SYSLOG_ACTION_SIZE_BUFFER, if
    dmesg_restrict==0.
  - nothing else (EPERM).

The use-cases were:
 - dmesg(1) needs to do non-destructive SYSLOG_ACTION_READ_ALLs.
 - sysklog(1) needs to open /proc/kmsg, drop privs, and still issue the
   destructive SYSLOG_ACTION_READs.

AIUI, dmesg(1) is moving to /dev/kmsg, and systemd-journald doesn't
clear the ring buffer.

Based on the comments in devkmsg_llseek, it sounds like actions besides
reading aren't going to be supported by /dev/kmsg (i.e.
SYSLOG_ACTION_CLEAR), so we have a strict subset of the non-destructive
syslog syscall actions.

To this end, move the check as Josh had done, but also rename the
constants to reflect their new uses (SYSLOG_FROM_CALL becomes
SYSLOG_FROM_READER, and SYSLOG_FROM_FILE becomes SYSLOG_FROM_PROC).
SYSLOG_FROM_READER allows non-destructive actions, and SYSLOG_FROM_PROC
allows destructive actions after a capabilities-constrained
SYSLOG_ACTION_OPEN check.

 - /dev/kmsg allows:
  - open if CAP_SYSLOG or dmesg_restrict==0
  - reading/polling, after open

Addresses https://bugzilla.redhat.com/show_bug.cgi?id=903192

[akpm@linux-foundation.org: use pr_warn_once()]
Signed-off-by: NKees Cook <keescook@chromium.org>
Reported-by: NChristian Kujau <lists@nerdbynature.de>
Tested-by: NJosh Boyer <jwboyer@redhat.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We recently noticed that reboot of a 1024 cpu machine takes approx 16
minutes of just stopping the cpus.  The slowdown was tracked to commit
f96972f2 ("kernel/sys.c: call disable_nonboot_cpus() in
kernel_restart()").

The current implementation does all the work of hot removing the cpus
before halting the system.  We are switching to just migrating to the
boot cpu and then continuing with shutdown/reboot.

This also has the effect of not breaking x86's command line parameter
for specifying the reboot cpu.  Note, this code was shamelessly copied
from arch/x86/kernel/reboot.c with bits removed pertaining to the
reboot_cpu command line parameter.
Signed-off-by: NRobin Holt <holt@sgi.com>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Russ Anderson <rja@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are instances in the kernel where we would like to disable CPU
hotplug (from sysfs) during some important operation.  Today the freezer
code depends on this and the code to do it was kinda tailor-made for
that.

Restructure the code and make it generic enough to be useful for other
usecases too.
Signed-off-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: NRobin Holt <holt@sgi.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Russ Anderson <rja@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull NVMe fixes from Matthew Wilcox.

* 'fixes-3.10' of git://git.infradead.org/users/willy/linux-nvme:
  NVMe: Add MSI support
  NVMe: Use dma_set_mask() correctly
  Return the result from user admin command IOCTL even in case of failure
  NVMe: Do not cancel command multiple times
  NVMe: fix error return code in nvme_submit_bio_queue()
  NVMe: check for integer overflow in nvme_map_user_pages()
  MAINTAINERS: update NVM EXPRESS DRIVER file list
  NVMe: Fix a signedness bug in nvme_trans_modesel_get_mp
  NVMe: Remove redundant version.h header include

Pull kvm bugfixes from Gleb Natapov:
 "There is one more fix for MIPS KVM ABI here, MIPS and PPC build
  breakage fixes and a couple of PPC bug fixes"

* 'fixes' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm/ppc/booke64: Fix lazy ee handling in kvmppc_handle_exit()
  kvm/ppc/booke: Hold srcu lock when calling gfn functions
  kvm/ppc/booke64: Disable e6500 support
  kvm/ppc/booke64: Fix AltiVec interrupt numbers and build breakage
  mips/kvm: Use KVM_REG_MIPS and proper size indicators for *_ONE_REG
  kvm: Add definition of KVM_REG_MIPS
  KVM: add kvm_para_available to asm-generic/kvm_para.h

EE is hard-disabled on entry to kvmppc_handle_exit(), so call
hard_irq_disable() so that PACA_IRQ_HARD_DIS is set, and soft_enabled
is unset.

Without this, we get warnings such as arch/powerpc/kernel/time.c:300,
and sometimes host kernel hangs.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

KVM core expects arch code to acquire the srcu lock when calling
gfn_to_memslot and similar functions.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

The previous patch made 64-bit booke KVM build again, but Altivec
support is still not complete, and we can't prevent the guest from
turning on Altivec (which can corrupt host state until state
save/restore is implemented).  Disable e6500 on KVM until this is
fixed.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Interrupt numbers defined for Book3E follows IVORs definition. Align
BOOKE_INTERRUPT_ALTIVEC_UNAVAIL and BOOKE_INTERRUPT_ALTIVEC_ASSIST to this
rule which also fixes the build breakage.
IVORs 32 and 33 are shared so reflect this in the interrupts naming.

This fixes a build break for 64-bit booke KVM.
Signed-off-by: NMihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

The API requires that the GET_ONE_REG and SET_ONE_REG ioctls have this
extra information encoded in the register identifiers.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

We use 0x7000000000000000ULL as 0x6000000000000000ULL is reserved for
ARM64.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

The stop machine logic can lock up if all but one of the migration
threads make it through the disable-irq step and the one remaining
thread gets stuck in __do_softirq.  The reason __do_softirq can hang is
that it has a bail-out based on jiffies timeout, but in the lockup case,
jiffies itself is not incremented.

To work around this, re-add the max_restart counter in __do_irq and stop
processing irqs after 10 restarts.

Thanks to Tejun Heo and Rusty Russell and others for helping me track
this down.

This was introduced in 3.9 by commit c10d7367 ("softirq: reduce
latencies").

It may be worth looking into ath9k to see if it has issues with its irq
handler at a later date.

The hang stack traces look something like this:

    ------------[ cut here ]------------
    WARNING: at kernel/watchdog.c:245 watchdog_overflow_callback+0x9c/0xa7()
    Watchdog detected hard LOCKUP on cpu 2
    Modules linked in: ath9k ath9k_common ath9k_hw ath mac80211 cfg80211 nfsv4 auth_rpcgss nfs fscache nf_nat_ipv4 nf_nat veth 8021q garp stp mrp llc pktgen lockd sunrpc]
    Pid: 23, comm: migration/2 Tainted: G         C   3.9.4+ #11
    Call Trace:
     <NMI>   warn_slowpath_common+0x85/0x9f
      warn_slowpath_fmt+0x46/0x48
      watchdog_overflow_callback+0x9c/0xa7
      __perf_event_overflow+0x137/0x1cb
      perf_event_overflow+0x14/0x16
      intel_pmu_handle_irq+0x2dc/0x359
      perf_event_nmi_handler+0x19/0x1b
      nmi_handle+0x7f/0xc2
      do_nmi+0xbc/0x304
      end_repeat_nmi+0x1e/0x2e
     <<EOE>>
      cpu_stopper_thread+0xae/0x162
      smpboot_thread_fn+0x258/0x260
      kthread+0xc7/0xcf
      ret_from_fork+0x7c/0xb0
    ---[ end trace 4947dfa9b0a4cec3 ]---
    BUG: soft lockup - CPU#1 stuck for 22s! [migration/1:17]
    Modules linked in: ath9k ath9k_common ath9k_hw ath mac80211 cfg80211 nfsv4 auth_rpcgss nfs fscache nf_nat_ipv4 nf_nat veth 8021q garp stp mrp llc pktgen lockd sunrpc]
    irq event stamp: 835637905
    hardirqs last  enabled at (835637904): __do_softirq+0x9f/0x257
    hardirqs last disabled at (835637905): apic_timer_interrupt+0x6d/0x80
    softirqs last  enabled at (5654720): __do_softirq+0x1ff/0x257
    softirqs last disabled at (5654725): irq_exit+0x5f/0xbb
    CPU 1
    Pid: 17, comm: migration/1 Tainted: G        WC   3.9.4+ #11 To be filled by O.E.M. To be filled by O.E.M./To be filled by O.E.M.
    RIP: tasklet_hi_action+0xf0/0xf0
    Process migration/1
    Call Trace:
     <IRQ>
      __do_softirq+0x117/0x257
      irq_exit+0x5f/0xbb
      smp_apic_timer_interrupt+0x8a/0x98
      apic_timer_interrupt+0x72/0x80
     <EOI>
      printk+0x4d/0x4f
      stop_machine_cpu_stop+0x22c/0x274
      cpu_stopper_thread+0xae/0x162
      smpboot_thread_fn+0x258/0x260
      kthread+0xc7/0xcf
      ret_from_fork+0x7c/0xb0
Signed-off-by: NBen Greear <greearb@candelatech.com>
Acked-by: NTejun Heo <tj@kernel.org>
Acked-by: NPekka Riikonen <priikone@iki.fi>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull net/9p bug fix from Eric Van Hensbergen:
 "zero copy error fix"

* tag '9p-3.10-bug-fix-1' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  net/9p: Handle error in zero copy request correctly for 9p2000.u

Pull spi fixes from Mark Brown:
 "A few nasty issues, particularly a race with the interrupt controller
  in the xilinx driver, together with a couple of more minor fixes and a
  much needed move of the mailing list away from sourceforge."

* tag 'spi-v3.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: hspi: fixup long delay time
  spi: spi-xilinx: Remove ISR race condition
  spi: topcliff-pch: fix error return code in pch_spi_probe()
  spi: topcliff-pch: Pass correct pointer to free_irq()
  spi: Move mailing list to vger

Merge tag 'stable/for-linus-3.10-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull xen fixes from Konrad Rzeszutek Wilk:
 "Two bug-fixes for regressions:
   - xen/tmem stopped working after a certain combination of
     modprobe/swapon was used
   - cpu online/offlining would trigger WARN_ON."

* tag 'stable/for-linus-3.10-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/tmem: Don't over-write tmem_frontswap_poolid after tmem_frontswap_init set it.
  xen/smp: Fixup NOHZ per cpu data when onlining an offline CPU.

Pull regmap fixes from Mark Brown:
 "The biggest fix here is Lars-Peter's fix for custom locking callbacks
  which is pretty localised but important for those devices that use the
  feature.  Otherwise we've got a couple of fairly small cleanups which
  would have been sent sooner were it not for letting Lars-Peter's patch
  soak for a while"

* tag 'regmap-v3.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: rbtree: Fixed node range check on sync
  regmap: regcache: Fixup locking for custom lock callbacks
  regmap: debugfs: Check return value of regmap_write()

Pull crypto fixes from Herbert Xu:
 "This fixes a build problem in sahara and temporarily disables two new
  optimisations because of performance regressions until a permanent fix
  is ready"

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: sahara - fix building as module
  crypto: blowfish - disable AVX2 implementation
  crypto: twofish - disable AVX2 implementation

Commit 10a7a077 ("xen: tmem: enable Xen
tmem shim to be built/loaded as a module") allows the tmem module
to be loaded any time. For this work the frontswap API had to
be able to asynchronously to call tmem_frontswap_init before
or after the swap image had been set. That was added in git
commit 905cd0e1
("mm: frontswap: lazy initialization to allow tmem backends to build/run as modules").

Which means we could do this (The common case):

 modprobe tmem		[so calls frontswap_register_ops, no ->init]
			 modifies tmem_frontswap_poolid = -1
 swapon /dev/xvda1	[__frontswap_init, calls -> init, tmem_frontswap_poolid is
			 < 0 so tmem hypercall done]

Or the failing one:

 swapon /dev/xvda1	[calls __frontswap_init, sets the need_init bitmap]
 modprobe tmem		[calls frontswap_register_ops, -->init calls, finds out
			tmem_frontswap_poolid is 0, does not make a hypercall.
			Later in the module_init, sets tmem_frontswap_poolid=-1]

Which meant that in the failing case we would not call the hypercall
to initialize the pool and never be able to make any frontswap
backend calls.

Moving the frontswap_register_ops after setting the tmem_frontswap_poolid
fixes it.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NBob Liu <bob.liu@oracle.com>

Pull powerpc fixes from Benjamin Herrenschmidt:
 "This is purely regressions (though not all recent ones) or stable
  material"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc: Partial revert of "Context switch more PMU related SPRs"
  powerpc/perf: Fix deadlock caused by calling printk() in PMU exception
  powerpc/hw_breakpoints: Add DABRX cpu feature to fix 32-bit regression
  powerpc/power8: Update denormalization handler
  powerpc/pseries: Simplify denormalization handler
  powerpc/power8: Fix oprofile and perf
  powerpc/eeh: Don't check RTAS token to get PE addr
  powerpc/pci: Check the bus address instead of resource address in pcibios_fixup_resources