This is the s390 version of 875ebe94 ("powerpc/smp: Wait until secondaries
are active & online").
The race described in length within the commit message is also possible on s390
and every other architecture. So fix this race on s390 as well.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Sebastian reported a crash caused by a jump label mismatch after resume.
This happens because we do not save the kernel text section during suspend
and therefore also do not restore it during resume, but use the kernel image
that restores the old system.

This means that after a suspend/resume cycle we lost all modifications done
to the kernel text section.
The reason for this is the pfn_is_nosave() function, which incorrectly
returns that read-only pages don't need to be saved. This is incorrect since
we mark the kernel text section read-only.
We still need to make sure to not save and restore pages contained within
NSS and DCSS segment.
To fix this add an extra case for the kernel text section and only save
those pages if they are not contained within an NSS segment.

Fixes the following crash (and the above bugs as well):

Jump label code mismatch at netif_receive_skb_internal+0x28/0xd0
Found:    c0 04 00 00 00 00
Expected: c0 f4 00 00 00 11
New:      c0 04 00 00 00 00
Kernel panic - not syncing: Corrupted kernel text
CPU: 0 PID: 9 Comm: migration/0 Not tainted 3.19.0-01975-gb1b096e70f23 #4
Call Trace:
  [<0000000000113972>] show_stack+0x72/0xf0
  [<000000000081f15e>] dump_stack+0x6e/0x90
  [<000000000081c4e8>] panic+0x108/0x2b0
  [<000000000081be64>] jump_label_bug.isra.2+0x104/0x108
  [<0000000000112176>] __jump_label_transform+0x9e/0xd0
  [<00000000001121e6>] __sm_arch_jump_label_transform+0x3e/0x50
  [<00000000001d1136>] multi_cpu_stop+0x12e/0x170
  [<00000000001d1472>] cpu_stopper_thread+0xb2/0x168
  [<000000000015d2ac>] smpboot_thread_fn+0x134/0x1b0
  [<0000000000158baa>] kthread+0x10a/0x110
  [<0000000000824a86>] kernel_thread_starter+0x6/0xc
Reported-and-tested-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Git commit d97d929f ("s390: move cacheinfo sysfs to generic cacheinfo
infrastructure") removed the general-instructions-extension availability
check before the ecag instruction is executed.
Without this check this may lead to crashes on machines without this facility.
Therefore add the check again where needed.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Given that sizeof(long) is now always 8, we can simplify syscall_get_arch()
a bit.
Just another piece I didn't find when removing 31 bit support.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add a BUILD_BUG_ON() to enforce that irqclass_sub_desc contains the required
number of defined interrupt descriptions and won't be filled up with zeros.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Rename two more files which I forgot. Also remove the "asm" from the
swsusp_asm64.S file, since the ".S" suffix already makes it obvious
that this file contains assembler code.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

ipl.c uses 3 different macros to create a sysfs show function for ipl
attributes. Define IPL_ATTR_SHOW_FN which is used by all macros.
Reviewed-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Use macros wherever applicable and create a shutdown_action attribute
group to simplify the code.
Reviewed-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Use macros wherever applicable and put bin_attributes inside attribute_groups
to simplify/remove some code.
Reviewed-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove __user address space annotation for sim_stor_event() calls since it
generates false positive warnings from sparse.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

As reported by sparse these can and should be static.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Use the sturg instruction instead of the stura instruction. This allows to
modify up to eight bytes in a row instead of only four.

For function tracer enabling and disabling this reduces the time needed to
modify the text sections by 50%, since for each mcount call site six bytes
need to be changed.

Also remove the EXTABLE entries, since calls to this function are not
supposed to fail.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove the s390 architecture implementation of probe_kernel_write() and
instead use a new function s390_kernel_write() to modify kernel text and
data everywhere.

The s390 implementation of probe_kernel_write() was potentially broken
since it modified memory in a read-modify-write fashion, which read four
bytes, modified the requested bytes within those four bytes and wrote
the result back.
If two cpus would modify the same four byte area at different locations
within that area, this could lead to corruption.
Right now the only places which called probe_kernel_write() did run within
stop_machine_run. Therefore the scenario can't happen right now, however
that might change at any time.

To fix this rename probe_kernel_write() to s390_kernel_write() which can
have special semantics, like only call it while running within stop_machine().
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

This patch extends the diag288 watchdog driver to be able to deal with KVM
hypervisors. Only z/VM needs special handling, we can use the same interface
as on LPAR. Remove all pr_info output to avoid misconception. Because there
is no value in these messages and only the pr_err messages make sense.
Signed-off-by: NXu Wang <gesaint@linux.vnet.ibm.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

There's no reason why we wouldn't want to be able to send a keep alive
message to /dev/watchdog (feed dog) for the s390 diag288 watchdog, so
let's enable the WDIOF_KEEPALIVEPING option.
Signed-off-by: NXu Wang <gesaint@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove the hard coded scheduler for the DASD device driver to enable
change of the scheduler during runtime. Set recommended deadline
scheduler via additional udev rule.
Signed-off-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

In case of a translation exception the page tables are corrupted. If the
exception handler then calls die() which again calls show_regs()
-> show_code() -> copy_from_user(), the kernel may access the same memory
location again and generates yet another translation exception. Which in turn
will lead to a deadlock on the die_lock spinlock, which the kernel tries to
grab recursively.

Given that the page tables are corrupted anyway, if we see such an exception,
let's simply panic.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Given that the kernel now always runs in 64 bit mode, it is
pointless to check if the z/Architecture mode is active.
Remove the checks.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Since sizeof(long) == 4 is always false now, simplify cmpxchg_double a bit.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove the 31 bit syscalls from the syscall table. This is a separate patch
just in case I screwed something up so it can be easily reverted.
However the conversion was done with a script, so everything should be ok.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Rename a couple of files to get rid of the "64" suffix.
"git blame" will still work.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.

The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062e ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.

Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

After a suspend/resume cycle we missed to enable smt again, which leads
to all sorts of bugs, since the kernel assumes smt is enabled, while the
hardware thinks it is not.
Reported-and-tested-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Reported-by: NStefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

For compat tasks the mmap randomization does not use the maximum
randomization value from mmap_rnd_mask but the fixed value of 0x7ff.
This needs to be respected in the definition of STACK_RND_MASK as
well.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The SF_CYCLES_BASIC_DIAG is always registered even if it is turned of in the
current hardware configuration.  Because diagnostic-sampling is typically not
turned on in the hardware configuration, do not register this perf event by
default.  Enable it only if the diagnostic-sampling function is authorized.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Merge misc fixes from Andrew Morton:
 "13 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  memcg: disable hierarchy support if bound to the legacy cgroup hierarchy
  mm: reorder can_do_mlock to fix audit denial
  kasan, module: move MODULE_ALIGN macro into <linux/moduleloader.h>
  kasan, module, vmalloc: rework shadow allocation for modules
  fanotify: fix event filtering with FAN_ONDIR set
  mm/nommu.c: export symbol max_mapnr
  arch/c6x/include/asm/pgtable.h: define dummy pgprot_writecombine for !MMU
  nilfs2: fix deadlock of segment constructor during recovery
  mm: cma: fix CMA aligned offset calculation
  mm, hugetlb: close race when setting PageTail for gigantic pages
  mm, oom: do not fail __GFP_NOFAIL allocation if oom killer is disabled
  drivers/rtc/rtc-s3c.c: add .needs_src_clk to s3c6410 RTC data
  ocfs2: make append_dio an incompat feature

If the memory cgroup controller is initially mounted in the scope of the
default cgroup hierarchy and then remounted to a legacy hierarchy, it will
still have hierarchy support enabled, which is incorrect.  We should
disable hierarchy support if bound to the legacy cgroup hierarchy.
Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A userspace call to mmap(MAP_LOCKED) may result in the successful locking
of memory while also producing a confusing audit log denial.  can_do_mlock
checks capable and rlimit.  If either of these return positive
can_do_mlock returns true.  The capable check leads to an LSM hook used by
apparmour and selinux which produce the audit denial.  Reordering so
rlimit is checked first eliminates the denial on success, only recording a
denial when the lock is unsuccessful as a result of the denial.
Signed-off-by: NJeff Vander Stoep <jeffv@google.com>
Acked-by: NNick Kralevich <nnk@google.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Paul Cassella <cassella@cray.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/moduleloader.h is more suitable place for this macro.
Also change alignment to PAGE_SIZE for CONFIG_KASAN=n as such
alignment already assumed in several places.
Signed-off-by: NAndrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Current approach in handling shadow memory for modules is broken.

Shadow memory could be freed only after memory shadow corresponds it is no
longer used.  vfree() called from interrupt context could use memory its
freeing to store 'struct llist_node' in it:

    void vfree(const void *addr)
    {
    ...
        if (unlikely(in_interrupt())) {
            struct vfree_deferred *p = this_cpu_ptr(&vfree_deferred);
            if (llist_add((struct llist_node *)addr, &p->list))
                    schedule_work(&p->wq);

Later this list node used in free_work() which actually frees memory.
Currently module_memfree() called in interrupt context will free shadow
before freeing module's memory which could provoke kernel crash.

So shadow memory should be freed after module's memory.  However, such
deallocation order could race with kasan_module_alloc() in module_alloc().

Free shadow right before releasing vm area.  At this point vfree()'d
memory is not used anymore and yet not available for other allocations.
New VM_KASAN flag used to indicate that vm area has dynamically allocated
shadow memory so kasan frees shadow only if it was previously allocated.
Signed-off-by: NAndrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With FAN_ONDIR set, the user can end up getting events, which it hasn't
marked.  This was revealed with fanotify04 testcase failure on
Linux-4.0-rc1, and is a regression from 3.19, revealed with 66ba93c0
("fanotify: don't set FAN_ONDIR implicitly on a marks ignored mask").

   # /opt/ltp/testcases/bin/fanotify04
   [ ... ]
  fanotify04    7  TPASS  :  event generated properly for type 100000
  fanotify04    8  TFAIL  :  fanotify04.c:147: got unexpected event 30
  fanotify04    9  TPASS  :  No event as expected

The testcase sets the adds the following marks : FAN_OPEN | FAN_ONDIR for
a fanotify on a dir.  Then does an open(), followed by close() of the
directory and expects to see an event FAN_OPEN(0x20).  However, the
fanotify returns (FAN_OPEN|FAN_CLOSE_NOWRITE(0x10)).  This happens due to
the flaw in the check for event_mask in fanotify_should_send_event() which
does:

	if (event_mask & marks_mask & ~marks_ignored_mask)
		return true;

where, event_mask == (FAN_ONDIR | FAN_CLOSE_NOWRITE),
       marks_mask == (FAN_ONDIR | FAN_OPEN),
       marks_ignored_mask == 0

Fix this by masking the outgoing events to the user, as we already take
care of FAN_ONDIR and FAN_EVENT_ON_CHILD.
Signed-off-by: NSuzuki K. Poulose <suzuki.poulose@arm.com>
Tested-by: NLino Sanfilippo <LinoSanfilippo@gmx.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Cc: Eric Paris <eparis@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Several modules may need max_mapnr, so export, the related error with
allmodconfig under c6x:

  MODPOST 3327 modules
  ERROR: "max_mapnr" [fs/pstore/ramoops.ko] undefined!
  ERROR: "max_mapnr" [drivers/media/v4l2-core/videobuf2-dma-contig.ko] undefined!
Signed-off-by: NChen Gang <gang.chen.5i5j@gmail.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When !MMU, asm-generic will not define default pgprot_writecombine, so c6x
needs to define it by itself.  The related error:

    CC [M]  fs/pstore/ram_core.o
  fs/pstore/ram_core.c: In function 'persistent_ram_vmap':
  fs/pstore/ram_core.c:399:10: error: implicit declaration of function 'pgprot_writecombine' [-Werror=implicit-function-declaration]
     prot = pgprot_writecombine(PAGE_KERNEL);
            ^
  fs/pstore/ram_core.c:399:8: error: incompatible types when assigning to type 'pgprot_t {aka struct <anonymous>}' from type 'int'
     prot = pgprot_writecombine(PAGE_KERNEL);
          ^
Signed-off-by: NChen Gang <gang.chen.5i5j@gmail.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

According to a report from Yuxuan Shui, nilfs2 in kernel 3.19 got stuck
during recovery at mount time.  The code path that caused the deadlock was
as follows:

  nilfs_fill_super()
    load_nilfs()
      nilfs_salvage_orphan_logs()
        * Do roll-forwarding, attach segment constructor for recovery,
          and kick it.

        nilfs_segctor_thread()
          nilfs_segctor_thread_construct()
           * A lock is held with nilfs_transaction_lock()
             nilfs_segctor_do_construct()
               nilfs_segctor_drop_written_files()
                 iput()
                   iput_final()
                     write_inode_now()
                       writeback_single_inode()
                         __writeback_single_inode()
                           do_writepages()
                             nilfs_writepage()
                               nilfs_construct_dsync_segment()
                                 nilfs_transaction_lock() --> deadlock

This can happen if commit 7ef3ff2f ("nilfs2: fix deadlock of segment
constructor over I_SYNC flag") is applied and roll-forward recovery was
performed at mount time.  The roll-forward recovery can happen if datasync
write is done and the file system crashes immediately after that.  For
instance, we can reproduce the issue with the following steps:

 < nilfs2 is mounted on /nilfs (device: /dev/sdb1) >
 # dd if=/dev/zero of=/nilfs/test bs=4k count=1 && sync
 # dd if=/dev/zero of=/nilfs/test conv=notrunc oflag=dsync bs=4k
 count=1 && reboot -nfh
 < the system will immediately reboot >
 # mount -t nilfs2 /dev/sdb1 /nilfs

The deadlock occurs because iput() can run segment constructor through
writeback_single_inode() if MS_ACTIVE flag is not set on sb->s_flags.  The
above commit changed segment constructor so that it calls iput()
asynchronously for inodes with i_nlink == 0, but that change was
imperfect.

This fixes the another deadlock by deferring iput() in segment constructor
even for the case that mount is not finished, that is, for the case that
MS_ACTIVE flag is not set.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Reported-by: NYuxuan Shui <yshuiv7@gmail.com>
Tested-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
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>

The CMA aligned offset calculation is incorrect for non-zero order_per_bit
values.

For example, if cma->order_per_bit=1, cma->base_pfn= 0x2f800000 and
align_order=12, the function returns a value of 0x17c00 instead of 0x400.

This patch fixes the CMA aligned offset calculation.

The previous calculation was wrong and would return too-large values for
the offset, so that when cma_alloc looks for free pages in the bitmap with
the requested alignment > order_per_bit, it starts too far into the bitmap
and so CMA allocations will fail despite there actually being plenty of
free pages remaining.  It will also probably have the wrong alignment.
With this change, we will get the correct offset into the bitmap.

One affected user is powerpc KVM, which has kvm_cma->order_per_bit set to
KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, or 18 - 12 = 6.

[gregory.0xf0@gmail.com: changelog additions]
Signed-off-by: NDanesh Petigara <dpetigara@broadcom.com>
Reviewed-by: NGregory Fong <gregory.0xf0@gmail.com>
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that gigantic pages are dynamically allocatable, care must be taken to
ensure that p->first_page is valid before setting PageTail.

If this isn't done, then it is possible to race and have compound_head()
return NULL.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NDavidlohr Bueso <dave@stgolabs.net>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Tetsuo Handa has pointed out that __GFP_NOFAIL allocations might fail
after OOM killer is disabled if the allocation is performed by a kernel
thread.  This behavior was introduced from the very beginning by
7f33d49a ("mm, PM/Freezer: Disable OOM killer when tasks are frozen").
 This means that the basic contract for the allocation request is broken
and the context requesting such an allocation might blow up unexpectedly.

There are basically two ways forward.

1) move oom_killer_disable after kernel threads are frozen.  This has a
   risk that the OOM victim wouldn't be able to finish because it would
   depend on an already frozen kernel thread.  This would be really tricky
   to debug.

2) do not fail GFP_NOFAIL allocation no matter what and risk a
   potential Freezable kernel threads will loop and fail the suspend.
   Incidental allocations after kernel threads are frozen will at least
   dump a warning - if we are lucky and the serial console is still active
   of course...

This patch implements the later option because it is safer.  We would see
warning rather than allocation failures for the kernel threads which would
blow up otherwise and have a higher chances to identify __GFP_NOFAIL users
from deeper pm code.
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Acked-by: NDavid Rientjes <rientjes@gooogle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit df9e26d0 ("rtc: s3c: add support for RTC of Exynos3250 SoC")
added an "rtc_src" DT property to specify the clock used as a source to
the S3C real-time clock.

Not all SoCs needs this so commit eaf3a659 ("drivers/rtc/rtc-s3c.c:
fix initialization failure without rtc source clock") changed to check
the struct s3c_rtc_data .needs_src_clk to conditionally grab the clock.

But that commit didn't update the data for each IP version so the RTC
broke on the boards that needs a source clock. This is the case of at
least Exynos5250 and Exynos5440 which uses the s3c6410 RTC IP block.

This commit fixes the S3C rtc on the Exynos5250 Snow and Exynos5420
Peach Pit and Pi Chromebooks.
Signed-off-by: NJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Tyler Baker <tyler.baker@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>