SELinux: Fix kernel BUG on empty security contexts.

commit 2172fa709ab32ca60e86179dc67d0857be8e2c98 upstream.

Setting an empty security context (length=0) on a file will
lead to incorrectly dereferencing the type and other fields
of the security context structure, yielding a kernel BUG.
As a zero-length security context is never valid, just reject
all such security contexts whether coming from userspace
via setxattr or coming from the filesystem upon a getxattr
request by SELinux.

Setting a security context value (empty or otherwise) unknown to
SELinux in the first place is only possible for a root process
(CAP_MAC_ADMIN), and, if running SELinux in enforcing mode, only
if the corresponding SELinux mac_admin permission is also granted
to the domain by policy.  In Fedora policies, this is only allowed for
specific domains such as livecd for setting down security contexts
that are not defined in the build host policy.

Reproducer:
su
setenforce 0
touch foo
setfattr -n security.selinux foo

Caveat:
Relabeling or removing foo after doing the above may not be possible
without booting with SELinux disabled.  Any subsequent access to foo
after doing the above will also trigger the BUG.

BUG output from Matthew Thode:
[  473.893141] ------------[ cut here ]------------
[  473.962110] kernel BUG at security/selinux/ss/services.c:654!
[  473.995314] invalid opcode: 0000 [#6] SMP
[  474.027196] Modules linked in:
[  474.058118] CPU: 0 PID: 8138 Comm: ls Tainted: G      D   I
3.13.0-grsec #1
[  474.116637] Hardware name: Supermicro X8ST3/X8ST3, BIOS 2.0
07/29/10
[  474.149768] task: ffff8805f50cd010 ti: ffff8805f50cd488 task.ti:
ffff8805f50cd488
[  474.183707] RIP: 0010:[<ffffffff814681c7>]  [<ffffffff814681c7>]
context_struct_compute_av+0xce/0x308
[  474.219954] RSP: 0018:ffff8805c0ac3c38  EFLAGS: 00010246
[  474.252253] RAX: 0000000000000000 RBX: ffff8805c0ac3d94 RCX:
0000000000000100
[  474.287018] RDX: ffff8805e8aac000 RSI: 00000000ffffffff RDI:
ffff8805e8aaa000
[  474.321199] RBP: ffff8805c0ac3cb8 R08: 0000000000000010 R09:
0000000000000006
[  474.357446] R10: 0000000000000000 R11: ffff8805c567a000 R12:
0000000000000006
[  474.419191] R13: ffff8805c2b74e88 R14: 00000000000001da R15:
0000000000000000
[  474.453816] FS:  00007f2e75220800(0000) GS:ffff88061fc00000(0000)
knlGS:0000000000000000
[  474.489254] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  474.522215] CR2: 00007f2e74716090 CR3: 00000005c085e000 CR4:
00000000000207f0
[  474.556058] Stack:
[  474.584325]  ffff8805c0ac3c98 ffffffff811b549b ffff8805c0ac3c98
ffff8805f1190a40
[  474.618913]  ffff8805a6202f08 ffff8805c2b74e88 00068800d0464990
ffff8805e8aac860
[  474.653955]  ffff8805c0ac3cb8 000700068113833a ffff880606c75060
ffff8805c0ac3d94
[  474.690461] Call Trace:
[  474.723779]  [<ffffffff811b549b>] ? lookup_fast+0x1cd/0x22a
[  474.778049]  [<ffffffff81468824>] security_compute_av+0xf4/0x20b
[  474.811398]  [<ffffffff8196f419>] avc_compute_av+0x2a/0x179
[  474.843813]  [<ffffffff8145727b>] avc_has_perm+0x45/0xf4
[  474.875694]  [<ffffffff81457d0e>] inode_has_perm+0x2a/0x31
[  474.907370]  [<ffffffff81457e76>] selinux_inode_getattr+0x3c/0x3e
[  474.938726]  [<ffffffff81455cf6>] security_inode_getattr+0x1b/0x22
[  474.970036]  [<ffffffff811b057d>] vfs_getattr+0x19/0x2d
[  475.000618]  [<ffffffff811b05e5>] vfs_fstatat+0x54/0x91
[  475.030402]  [<ffffffff811b063b>] vfs_lstat+0x19/0x1b
[  475.061097]  [<ffffffff811b077e>] SyS_newlstat+0x15/0x30
[  475.094595]  [<ffffffff8113c5c1>] ? __audit_syscall_entry+0xa1/0xc3
[  475.148405]  [<ffffffff8197791e>] system_call_fastpath+0x16/0x1b
[  475.179201] Code: 00 48 85 c0 48 89 45 b8 75 02 0f 0b 48 8b 45 a0 48
8b 3d 45 d0 b6 00 8b 40 08 89 c6 ff ce e8 d1 b0 06 00 48 85 c0 49 89 c7
75 02 <0f> 0b 48 8b 45 b8 4c 8b 28 eb 1e 49 8d 7d 08 be 80 01 00 00 e8
[  475.255884] RIP  [<ffffffff814681c7>]
context_struct_compute_av+0xce/0x308
[  475.296120]  RSP <ffff8805c0ac3c38>
[  475.328734] ---[ end trace f076482e9d754adc ]---

Reported-by:  Matthew Thode <mthode@mthode.org>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: __set_page_dirty_nobuffers() uses spin_lock_irqsave() instead of spin_lock_irq()

commit a85d9df1ea1d23682a0ed1e100e6965006595d06 upstream.

During aio stress test, we observed the following lockdep warning.  This
mean AIO+numa_balancing is currently deadlockable.

The problem is, aio_migratepage disable interrupt, but
__set_page_dirty_nobuffers unintentionally enable it again.

Generally, all helper function should use spin_lock_irqsave() instead of
spin_lock_irq() because they don't know caller at all.

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

          CPU0
          ----
     lock(&(&ctx->completion_lock)->rlock);
     <Interrupt>
       lock(&(&ctx->completion_lock)->rlock);

    *** DEADLOCK ***

      dump_stack+0x19/0x1b
      print_usage_bug+0x1f7/0x208
      mark_lock+0x21d/0x2a0
      mark_held_locks+0xb9/0x140
      trace_hardirqs_on_caller+0x105/0x1d0
      trace_hardirqs_on+0xd/0x10
      _raw_spin_unlock_irq+0x2c/0x50
      __set_page_dirty_nobuffers+0x8c/0xf0
      migrate_page_copy+0x434/0x540
      aio_migratepage+0xb1/0x140
      move_to_new_page+0x7d/0x230
      migrate_pages+0x5e5/0x700
      migrate_misplaced_page+0xbc/0xf0
      do_numa_page+0x102/0x190
      handle_pte_fault+0x241/0x970
      handle_mm_fault+0x265/0x370
      __do_page_fault+0x172/0x5a0
      do_page_fault+0x1a/0x70
      page_fault+0x28/0x30

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: __set_page_dirty uses spin_lock_irqsave instead of spin_lock_irq

commit 227d53b397a32a7614667b3ecaf1d89902fb6c12 upstream.

To use spin_{un}lock_irq is dangerous if caller disabled interrupt.
During aio buffer migration, we have a possibility to see the following
call stack.

aio_migratepage  [disable interrupt]
  migrate_page_copy
    clear_page_dirty_for_io
      set_page_dirty
        __set_page_dirty_buffers
          __set_page_dirty
            spin_lock_irq

This mean, current aio migration is a deadlockable.  spin_lock_irqsave
is a safer alternative and we should use it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: David Rientjes rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86, hweight: Fix BUG when booting with CONFIG_GCOV_PROFILE_ALL=y

commit 6583327c4dd55acbbf2a6f25e775b28b3abf9a42 upstream.

Commit d61931d89b, "x86: Add optimized popcnt variants" introduced
compile flag -fcall-saved-rdi for lib/hweight.c. When combined with
options -fprofile-arcs and -O2, this flag causes gcc to generate
broken constructor code. As a result, a 64 bit x86 kernel compiled
with CONFIG_GCOV_PROFILE_ALL=y prints message "gcov: could not create
file" and runs into sproadic BUGs during boot.

The gcc people indicate that these kinds of problems are endemic when
using ad hoc calling conventions.  It is therefore best to treat any
file compiled with ad hoc calling conventions as an isolated
environment and avoid things like profiling or coverage analysis,
since those subsystems assume a "normal" calling conventions.

This patch avoids the bug by excluding lib/hweight.o from coverage
profiling.

Reported-by: Meelis Roos <mroos@linux.ee>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/52F3A30C.7050205@linux.vnet.ibm.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
printk: Fix scheduling-while-atomic problem in console_cpu_notify()

commit 85eae82a0855d49852b87deac8653e4ebc8b291f upstream.

The console_cpu_notify() function runs with interrupts disabled in the
CPU_DYING case.  It therefore cannot block, for example, as will happen
when it calls console_lock().  Therefore, remove the CPU_DYING leg of
the switch statement to avoid this problem.

Change-Id: Ic3a23b1889dcbdb25c10a3c1f5905b50ee43adf6
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Guillaume Morin <guillaume@morinfr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ext4: protect group inode free counting with group lock

commit 6f2e9f0e7d795214b9cf5a47724a273b705fd113 upstream.

Now when we set the group inode free count, we don't have a proper
group lock so that multiple threads may decrease the inode free
count at the same time. And e2fsck will complain something like:

Free inodes count wrong for group #1 (1, counted=0).
Fix? no

Free inodes count wrong for group #2 (3, counted=0).
Fix? no

Directories count wrong for group #2 (780, counted=779).
Fix? no

Free inodes count wrong for group #3 (2272, counted=2273).
Fix? no

So this patch try to protect it with the ext4_lock_group.

btw, it is found by xfstests test case 269 and the volume is
mkfsed with the parameter
"-O ^resize_inode,^uninit_bg,extent,meta_bg,flex_bg,ext_attr"
and I have run it 100 times and the error in e2fsck doesn't
show up again.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drm/i915: kick any firmware framebuffers before claiming the gtt

commit 9f846a16d213523fbe6daea17e20df6b8ac5a1e5 upstream.

Especially vesafb likes to map everything as uc- (yikes), and if that
mapping hangs around still while we try to map the gtt as wc the
kernel will downgrade our request to uc-, resulting in abyssal
performance.

Unfortunately we can't do this as early as readon does (i.e. as the
first thing we do when initializing the hw) because our fb/mmio space
region moves around on a per-gen basis. So I've had to move it below
the gtt initialization, but that seems to work, too. The important
thing is that we do this before we set up the gtt wc mapping.

Now an altogether different question is why people compile their
kernels with vesafb enabled, but I guess making things just work isn't
bad per se ...

v2:
- s/radeondrmfb/inteldrmfb/
- fix up error handling

v3: Kill #ifdef X86, this is Intel after all. Noticed by Ben Widawsky.

v4: Jani Nikula complained about the pointless bool primary
initialization.

v5: Don't oops if we can't allocate, noticed by Chris Wilson.

v6: Resolve conflicts with agp rework and fixup whitespace.

This is commit e188719a2891f01b3100d in drm-next.

Backport to 3.5 -fixes queue requested by Dave Airlie - due to grub
using vesa on fedora their initrd seems to load vesafb before loading
the real kms driver. So tons more people actually experience a
dead-slow gpu. Hence also the Cc: stable.

Reported-and-tested-by: "Kilarski, Bernard R" <bernard.r.kilarski@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm/page_alloc.c: remove pageblock_default_order()

commit 955c1cd7401565671b064e499115344ec8067dfd upstream.

This has always been broken: one version takes an unsigned int and the
other version takes no arguments.  This bug was hidden because one
version of set_pageblock_order() was a macro which doesn't evaluate its
argument.

Simplify it all and remove pageblock_default_order() altogether.

Reported-by: rajman mekaco <rajman.mekaco@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: setup pageblock_order before it's used by sparsemem

commit ca57df79d4f64e1a4886606af4289d40636189c5 upstream.

On architectures with CONFIG_HUGETLB_PAGE_SIZE_VARIABLE set, such as
Itanium, pageblock_order is a variable with default value of 0.  It's set
to the right value by set_pageblock_order() in function
free_area_init_core().

But pageblock_order may be used by sparse_init() before free_area_init_core()
is called along path:
sparse_init()
    ->sparse_early_usemaps_alloc_node()
	->usemap_size()
	    ->SECTION_BLOCKFLAGS_BITS
		->((1UL << (PFN_SECTION_SHIFT - pageblock_order)) *
NR_PAGEBLOCK_BITS)

The uninitialized pageblock_size will cause memory wasting because
usemap_size() returns a much bigger value then it's really needed.

For example, on an Itanium platform,
sparse_init() pageblock_order=0 usemap_size=24576
free_area_init_core() before pageblock_order=0, usemap_size=24576
free_area_init_core() after pageblock_order=12, usemap_size=8

That means 24K memory has been wasted for each section, so fix it by calling
set_pageblock_order() from sparse_init().

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Jiang Liu <liuj97@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Keping Chen <chenkeping@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Conflicts:
	mm/internal.h

Change-Id: If0f517ff1d34b70c497364b9cb038fc683f9cd92
dm sysfs: fix a module unload race

commit 2995fa78e423d7193f3b57835f6c1c75006a0315 upstream.

This reverts commit be35f48610 ("dm: wait until embedded kobject is
released before destroying a device") and provides an improved fix.

The kobject release code that calls the completion must be placed in a
non-module file, otherwise there is a module unload race (if the process
calling dm_kobject_release is preempted and the DM module unloaded after
the completion is triggered, but before dm_kobject_release returns).

To fix this race, this patch moves the completion code to dm-builtin.c
which is always compiled directly into the kernel if BLK_DEV_DM is
selected.

The patch introduces a new dm_kobject_holder structure, its purpose is
to keep the completion and kobject in one place, so that it can be
accessed from non-module code without the need to export the layout of
struct mapped_device to that code.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ftrace: Synchronize setting function_trace_op with ftrace_trace_function

commit 405e1d834807e51b2ebd3dea81cb51e53fb61504 upstream.

[ Partial commit backported to 3.4. The ftrace_sync() code by this is
  required for other fixes that 3.4 needs. ]

ftrace_trace_function is a variable that holds what function will be called
directly by the assembly code (mcount). If just a single function is
registered and it handles recursion itself, then the assembly will call that
function directly without any helper function. It also passes in the
ftrace_op that was registered with the callback. The ftrace_op to send is
stored in the function_trace_op variable.

The ftrace_trace_function and function_trace_op needs to be coordinated such
that the called callback wont be called with the wrong ftrace_op, otherwise
bad things can happen if it expected a different op. Luckily, there's no
callback that doesn't use the helper functions that requires this. But
there soon will be and this needs to be fixed.

Use a set_function_trace_op to store the ftrace_op to set the
function_trace_op to when it is safe to do so (during the update function
within the breakpoint or stop machine calls). Or if dynamic ftrace is not
being used (static tracing) then we have to do a bit more synchronization
when the ftrace_trace_function is set as that takes affect immediately
(as oppose to dynamic ftrace doing it with the modification of the trampoline).

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ftrace: Fix synchronization location disabling and freeing ftrace_ops

commit a4c35ed241129dd142be4cadb1e5a474a56d5464 upstream.

The synchronization needed after ftrace_ops are unregistered must happen
after the callback is disabled from becing called by functions.

The current location happens after the function is being removed from the
internal lists, but not after the function callbacks were disabled, leaving
the functions susceptible of being called after their callbacks are freed.

This affects perf and any externel users of function tracing (LTTng and
SystemTap).

Fixes: cdbe61bfe704 "ftrace: Allow dynamically allocated function tracers"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ftrace: Have function graph only trace based on global_ops filters

commit 23a8e8441a0a74dd612edf81dc89d1600bc0a3d1 upstream.

Doing some different tests, I discovered that function graph tracing, when
filtered via the set_ftrace_filter and set_ftrace_notrace files, does
not always keep with them if another function ftrace_ops is registered
to trace functions.

The reason is that function graph just happens to trace all functions
that the function tracer enables. When there was only one user of
function tracing, the function graph tracer did not need to worry about
being called by functions that it did not want to trace. But now that there
are other users, this becomes a problem.

For example, one just needs to do the following:

 # cd /sys/kernel/debug/tracing
 # echo schedule > set_ftrace_filter
 # echo function_graph > current_tracer
 # cat trace
[..]
 0)               |  schedule() {
 ------------------------------------------
 0)    <idle>-0    =>   rcu_pre-7
 ------------------------------------------

 0) ! 2980.314 us |  }
 0)               |  schedule() {
 ------------------------------------------
 0)   rcu_pre-7    =>    <idle>-0
 ------------------------------------------

 0) + 20.701 us   |  }

 # echo 1 > /proc/sys/kernel/stack_tracer_enabled
 # cat trace
[..]
 1) + 20.825 us   |      }
 1) + 21.651 us   |    }
 1) + 30.924 us   |  } /* SyS_ioctl */
 1)               |  do_page_fault() {
 1)               |    __do_page_fault() {
 1)   0.274 us    |      down_read_trylock();
 1)   0.098 us    |      find_vma();
 1)               |      handle_mm_fault() {
 1)               |        _raw_spin_lock() {
 1)   0.102 us    |          preempt_count_add();
 1)   0.097 us    |          do_raw_spin_lock();
 1)   2.173 us    |        }
 1)               |        do_wp_page() {
 1)   0.079 us    |          vm_normal_page();
 1)   0.086 us    |          reuse_swap_page();
 1)   0.076 us    |          page_move_anon_rmap();
 1)               |          unlock_page() {
 1)   0.082 us    |            page_waitqueue();
 1)   0.086 us    |            __wake_up_bit();
 1)   1.801 us    |          }
 1)   0.075 us    |          ptep_set_access_flags();
 1)               |          _raw_spin_unlock() {
 1)   0.098 us    |            do_raw_spin_unlock();
 1)   0.105 us    |            preempt_count_sub();
 1)   1.884 us    |          }
 1)   9.149 us    |        }
 1) + 13.083 us   |      }
 1)   0.146 us    |      up_read();

When the stack tracer was enabled, it enabled all functions to be traced, which
now the function graph tracer also traces. This is a side effect that should
not occur.

To fix this a test is added when the function tracing is changed, as well as when
the graph tracer is enabled, to see if anything other than the ftrace global_ops
function tracer is enabled. If so, then the graph tracer calls a test trampoline
that will look at the function that is being traced and compare it with the
filters defined by the global_ops.

As an optimization, if there's no other function tracers registered, or if
the only registered function tracers also use the global ops, the function
graph infrastructure will call the registered function graph callback directly
and not go through the test trampoline.

Fixes: d2d45c7a03a2 "tracing: Have stack_tracer use a separate list of functions"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sched/nohz: Fix rq->cpu_load[] calculations

commit 556061b00c9f2fd6a5524b6bde823ef12f299ecf upstream.

While investigating why the load-balancer did funny I found that the
rq->cpu_load[] tables were completely screwy.. a bit more digging
revealed that the updates that got through were missing ticks followed
by a catchup of 2 ticks.

The catchup assumes the cpu was idle during that time (since only nohz
can cause missed ticks and the machine is idle etc..) this means that
esp. the higher indices were significantly lower than they ought to
be.

The reason for this is that its not correct to compare against jiffies
on every jiffy on any other cpu than the cpu that updates jiffies.

This patch cludges around it by only doing the catch-up stuff from
nohz_idle_balance() and doing the regular stuff unconditionally from
the tick.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: pjt@google.com
Cc: Venkatesh Pallipadi <venki@google.com>
Link: http://lkml.kernel.org/n/tip-tp4kj18xdd5aj4vvj0qg55s2@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sched/nohz: Fix rq->cpu_load calculations some more

commit 5aaa0b7a2ed5b12692c9ffb5222182bd558d3146 upstream.

Follow up on commit 556061b00 ("sched/nohz: Fix rq->cpu_load[]
calculations") since while that fixed the busy case it regressed the
mostly idle case.

Add a callback from the nohz exit to also age the rq->cpu_load[]
array. This closes the hole where either there was no nohz load
balance pass during the nohz, or there was a 'significant' amount of
idle time between the last nohz balance and the nohz exit.

So we'll update unconditionally from the tick to not insert any
accidental 0 load periods while busy, and we try and catch up from
nohz idle balance and nohz exit. Both these are still prone to missing
a jiffy, but that has always been the case.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: pjt@google.com
Cc: Venkatesh Pallipadi <venki@google.com>
Link: http://lkml.kernel.org/n/tip-kt0trz0apodbf84ucjfdbr1a@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
IB/qib: Convert qib_user_sdma_pin_pages() to use get_user_pages_fast()

commit 603e7729920e42b3c2f4dbfab9eef4878cb6e8fa upstream.

qib_user_sdma_queue_pkts() gets called with mmap_sem held for
writing. Except for get_user_pages() deep down in
qib_user_sdma_pin_pages() we don't seem to need mmap_sem at all.  Even
more interestingly the function qib_user_sdma_queue_pkts() (and also
qib_user_sdma_coalesce() called somewhat later) call copy_from_user()
which can hit a page fault and we deadlock on trying to get mmap_sem
when handling that fault.

So just make qib_user_sdma_pin_pages() use get_user_pages_fast() and
leave mmap_sem locking for mm.

This deadlock has actually been observed in the wild when the node
is under memory pressure.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Roland Dreier <roland@purestorage.com>
[Backported to 3.4: (Thank to Ben Hutchings)
 - Adjust context
 - Adjust indentation and nr_pages argument in qib_user_sdma_pin_pages()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
target/file: Use O_DSYNC by default for FILEIO backends

commit a4dff3043c231d57f982af635c9d2192ee40e5ae upstream.

Convert to use O_DSYNC for all cases at FILEIO backend creation time to
avoid the extra syncing of pure timestamp updates with legacy O_SYNC during
default operation as recommended by hch.  Continue to do this independently of
Write Cache Enable (WCE) bit, as WCE=0 is currently the default for all backend
devices and enabled by user on per device basis via attrib/emulate_write_cache.

This patch drops the now unnecessary fd_buffered_io= token usage that was
originally signalling when to explictly disable O_SYNC at backend creation
time for buffered I/O operation.  This can end up being dangerous for a number
of reasons during physical node failure, so go ahead and drop this option
for now when O_DSYNC is used as the default.

Also allow explict FUA WRITEs -> vfs_fsync_range() call to function in
fd_execute_cmd() independently of WCE bit setting.

Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
[bwh: Backported to 3.2:
 - We have fd_do_task() and not fd_execute_cmd()
 - Various fields are in struct se_task rather than struct se_cmd
 - fd_create_virtdevice() flags initialisation hasn't been cleaned up]
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
target/file: Re-enable optional fd_buffered_io=1 operation

commit b32f4c7ed85c5cee2a21a55c9f59ebc9d57a2463 upstream.

This patch re-adds the ability to optionally run in buffered FILEIO mode
(eg: w/o O_DSYNC) for device backends in order to once again use the
Linux buffered cache as a write-back storage mechanism.

This logic was originally dropped with mainline v3.5-rc commit:

commit a4dff3043c231d57f982af635c9d2192ee40e5ae
Author: Nicholas Bellinger <nab@linux-iscsi.org>
Date:   Wed May 30 16:25:41 2012 -0700

    target/file: Use O_DSYNC by default for FILEIO backends

This difference with this patch is that fd_create_virtdevice() now
forces the explicit setting of emulate_write_cache=1 when buffered FILEIO
operation has been enabled.

(v2: Switch to FDBD_HAS_BUFFERED_IO_WCE + add more detailed
     comment as requested by hch)

Reported-by: Ferry <iscsitmp@bananateam.nl>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
KVM: Fix buffer overflow in kvm_set_irq()

commit f2ebd422f71cda9c791f76f85d2ca102ae34a1ed upstream.

kvm_set_irq() has an internal buffer of three irq routing entries, allowing
connecting a GSI to three IRQ chips or on MSI.  However setup_routing_entry()
does not properly enforce this, allowing three irqchip routes followed by
an MSI route to overflow the buffer.

Fix by ensuring that an MSI entry is added to an empty list.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PM / Hibernate: Hibernate/thaw fixes/improvements

commit 5a21d489fd9541a4a66b9a500659abaca1b19a51 upstream.

 1. Do not allocate memory for buffers from emergency pools, unless
    absolutely required. Do not warn about and do not retry non-essential
    failed allocations.

 2. Do not check the amount of free pages left on every single page
    write, but wait until one map is completely populated and then check.

 3. Set maximum number of pages for read buffering consistently, instead
    of inadvertently depending on the size of the sector type.

 4. Fix copyright line, which I missed when I submitted the hibernation
    threading patch.

 5. Dispense with bit shifting arithmetic to improve readability.

 6. Really recalculate the number of pages required to be free after all
    allocations have been done.

 7. Fix calculation of pages required for read buffering. Only count in
    pages that do not belong to high memory.

Signed-off-by: Bojan Smojver <bojan@rexursive.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>