PageTransHuge() can't guarantee the page is a transparent huge page
since it returns true for both transparent huge and hugetlbfs pages.

This patch fixes it by checking the page is also !hugetlbfs page.

Before patch:

[  121.571128] Injecting memory failure at pfn 23a200
[  121.571141] MCE 0x23a200: huge page recovery: Delayed
[  140.355100] MCE: Memory failure is now running on 0x23a200

After patch:

[   94.290793] Injecting memory failure at pfn 23a000
[   94.290800] MCE 0x23a000: huge page recovery: Delayed
[  105.722303] MCE: Software-unpoisoned page 0x23a000
Signed-off-by: NWanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

madvise_hwpoison won't check if the page is small page or huge page and
traverses in small page granularity against the range unconditionally,
which result in a printk flood "MCE xxx: already hardware poisoned" if
the page is a huge page.

This patch fixes it by using compound_order(compound_head(page)) for
huge page iterator.

Testcase:

#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <errno.h>

#define PAGES_TO_TEST 3
#define PAGE_SIZE	4096 * 512

int main(void)
{
	char *mem;
	int i;

	mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE,
			PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, 0, 0);

	if (madvise(mem, PAGES_TO_TEST * PAGE_SIZE, MADV_HWPOISON) == -1)
		return -1;

	munmap(mem, PAGES_TO_TEST * PAGE_SIZE);

	return 0;
}
Signed-off-by: NWanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Recently commit bab55417 ("block: support embedded device command
line partition") introduced CONFIG_CMDLINE_PARSER.  However, that name
is too generic and sounds like it enables/disables generic kernel boot
arg processing, when it really is block specific.

Before this option becomes a part of a full/final release, add the BLK_
prefix to it so that it is clear in absence of any other context that it
is block specific.

In addition, fix up the following less critical items:
 - help text was not really at all helpful.
 - index file for Documentation was not updated
 - add the new arg to Documentation/kernel-parameters.txt
 - clarify wording in source comments
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Cai Zhiyong <caizhiyong@huawei.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The function __munlock_pagevec_fill() introduced in commit 7a8010cd
("mm: munlock: manual pte walk in fast path instead of
follow_page_mask()") uses pmd_addr_end() for restricting its operation
within current page table.

This is insufficient on architectures/configurations where pmd is folded
and pmd_addr_end() just returns the end of the full range to be walked.
In this case, it allows pte++ to walk off the end of a page table
resulting in unpredictable behaviour.

This patch fixes the function by using pgd_addr_end() and pud_addr_end()
before pmd_addr_end(), which will yield correct page table boundary on
all configurations.  This is similar to what existing page walkers do
when walking each level of the page table.

Additionaly, the patch clarifies a comment for get_locked_pte() call in the
function.
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Reviewed-by: NBob Liu <bob.liu@oracle.com>
Cc: Jörn Engel <joern@logfs.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Isolated balloon pages can wrongly end up in LRU lists when
migrate_pages() finishes its round without draining all the isolated
page list.

The same issue can happen when reclaim_clean_pages_from_list() tries to
reclaim pages from an isolated page list, before migration, in the CMA
path.  Such balloon page leak opens a race window against LRU lists
shrinkers that leads us to the following kernel panic:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
  IP: [<ffffffff810c2625>] shrink_page_list+0x24e/0x897
  PGD 3cda2067 PUD 3d713067 PMD 0
  Oops: 0000 [#1] SMP
  CPU: 0 PID: 340 Comm: kswapd0 Not tainted 3.12.0-rc1-22626-g4367597 #87
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  RIP: shrink_page_list+0x24e/0x897
  RSP: 0000:ffff88003da499b8  EFLAGS: 00010286
  RAX: 0000000000000000 RBX: ffff88003e82bd60 RCX: 00000000000657d5
  RDX: 0000000000000000 RSI: 000000000000031f RDI: ffff88003e82bd40
  RBP: ffff88003da49ab0 R08: 0000000000000001 R09: 0000000081121a45
  R10: ffffffff81121a45 R11: ffff88003c4a9a28 R12: ffff88003e82bd40
  R13: ffff88003da0e800 R14: 0000000000000001 R15: ffff88003da49d58
  FS:  0000000000000000(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000067d9000 CR3: 000000003ace5000 CR4: 00000000000407b0
  Call Trace:
    shrink_inactive_list+0x240/0x3de
    shrink_lruvec+0x3e0/0x566
    __shrink_zone+0x94/0x178
    shrink_zone+0x3a/0x82
    balance_pgdat+0x32a/0x4c2
    kswapd+0x2f0/0x372
    kthread+0xa2/0xaa
    ret_from_fork+0x7c/0xb0
  Code: 80 7d 8f 01 48 83 95 68 ff ff ff 00 4c 89 e7 e8 5a 7b 00 00 48 85 c0 49 89 c5 75 08 80 7d 8f 00 74 3e eb 31 48 8b 80 18 01 00 00 <48> 8b 74 0d 48 8b 78 30 be 02 00 00 00 ff d2 eb
  RIP  [<ffffffff810c2625>] shrink_page_list+0x24e/0x897
   RSP <ffff88003da499b8>
  CR2: 0000000000000028
  ---[ end trace 703d2451af6ffbfd ]---
  Kernel panic - not syncing: Fatal exception

This patch fixes the issue, by assuring the proper tests are made at
putback_movable_pages() & reclaim_clean_pages_from_list() to avoid
isolated balloon pages being wrongly reinserted in LRU lists.

[akpm@linux-foundation.org: clarify awkward comment text]
Signed-off-by: NRafael Aquini <aquini@redhat.com>
Reported-by: NLuiz Capitulino <lcapitulino@redhat.com>
Tested-by: NLuiz Capitulino <lcapitulino@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The FAULT_FLAG_WRITE flag has been set based on uninitialized variable.

Fixes a regression added by commit 759496ba ("arch: mm: pass
userspace fault flag to generic fault handler")
Signed-off-by: NFelipe Pena <felipensp@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

patch(1) can't handle zero-length files - it appears to simply not create
the file, so my powerpc build fails.

Put something in here to make life easier.

Cc: Hugh Dickins <hughd@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Many NILFS2 users were reported about strange file system corruption
(for example):

   NILFS: bad btree node (blocknr=185027): level = 0, flags = 0x0, nchildren = 768
   NILFS error (device sda4): nilfs_bmap_last_key: broken bmap (inode number=11540)

But such error messages are consequence of file system's issue that takes
place more earlier.  Fortunately, Jerome Poulin <jeromepoulin@gmail.com>
and Anton Eliasson <devel@antoneliasson.se> were reported about another
issue not so recently.  These reports describe the issue with segctor
thread's crash:

  BUG: unable to handle kernel paging request at 0000000000004c83
  IP: nilfs_end_page_io+0x12/0xd0 [nilfs2]

  Call Trace:
   nilfs_segctor_do_construct+0xf25/0x1b20 [nilfs2]
   nilfs_segctor_construct+0x17b/0x290 [nilfs2]
   nilfs_segctor_thread+0x122/0x3b0 [nilfs2]
   kthread+0xc0/0xd0
   ret_from_fork+0x7c/0xb0

These two issues have one reason.  This reason can raise third issue
too.  Third issue results in hanging of segctor thread with eating of
100% CPU.

REPRODUCING PATH:

One of the possible way or the issue reproducing was described by
Jermoe me Poulin <jeromepoulin@gmail.com>:

1. init S to get to single user mode.
2. sysrq+E to make sure only my shell is running
3. start network-manager to get my wifi connection up
4. login as root and launch "screen"
5. cd /boot/log/nilfs which is a ext3 mount point and can log when NILFS dies.
6. lscp | xz -9e > lscp.txt.xz
7. mount my snapshot using mount -o cp=3360839,ro /dev/vgUbuntu/root /mnt/nilfs
8. start a screen to dump /proc/kmsg to text file since rsyslog is killed
9. start a screen and launch strace -f -o find-cat.log -t find
/mnt/nilfs -type f -exec cat {} > /dev/null \;
10. start a screen and launch strace -f -o apt-get.log -t apt-get update
11. launch the last command again as it did not crash the first time
12. apt-get crashes
13. ps aux > ps-aux-crashed.log
13. sysrq+W
14. sysrq+E  wait for everything to terminate
15. sysrq+SUSB

Simplified way of the issue reproducing is starting kernel compilation
task and "apt-get update" in parallel.

REPRODUCIBILITY:

The issue is reproduced not stable [60% - 80%].  It is very important to
have proper environment for the issue reproducing.  The critical
conditions for successful reproducing:

(1) It should have big modified file by mmap() way.

(2) This file should have the count of dirty blocks are greater that
    several segments in size (for example, two or three) from time to time
    during processing.

(3) It should be intensive background activity of files modification
    in another thread.

INVESTIGATION:

First of all, it is possible to see that the reason of crash is not valid
page address:

  NILFS [nilfs_segctor_complete_write]:2100 bh->b_count 0, bh->b_blocknr 13895680, bh->b_size 13897727, bh->b_page 0000000000001a82
  NILFS [nilfs_segctor_complete_write]:2101 segbuf->sb_segnum 6783

Moreover, value of b_page (0x1a82) is 6786.  This value looks like segment
number.  And b_blocknr with b_size values look like block numbers.  So,
buffer_head's pointer points on not proper address value.

Detailed investigation of the issue is discovered such picture:

  [-----------------------------SEGMENT 6783-------------------------------]
  NILFS [nilfs_segctor_do_construct]:2310 nilfs_segctor_begin_construction
  NILFS [nilfs_segctor_do_construct]:2321 nilfs_segctor_collect
  NILFS [nilfs_segctor_do_construct]:2336 nilfs_segctor_assign
  NILFS [nilfs_segctor_do_construct]:2367 nilfs_segctor_update_segusage
  NILFS [nilfs_segctor_do_construct]:2371 nilfs_segctor_prepare_write
  NILFS [nilfs_segctor_do_construct]:2376 nilfs_add_checksums_on_logs
  NILFS [nilfs_segctor_do_construct]:2381 nilfs_segctor_write
  NILFS [nilfs_segbuf_submit_bio]:464 bio->bi_sector 111149024, segbuf->sb_segnum 6783

  [-----------------------------SEGMENT 6784-------------------------------]
  NILFS [nilfs_segctor_do_construct]:2310 nilfs_segctor_begin_construction
  NILFS [nilfs_segctor_do_construct]:2321 nilfs_segctor_collect
  NILFS [nilfs_lookup_dirty_data_buffers]:782 bh->b_count 1, bh->b_page ffffea000709b000, page->index 0, i_ino 1033103, i_size 25165824
  NILFS [nilfs_lookup_dirty_data_buffers]:783 bh->b_assoc_buffers.next ffff8802174a6798, bh->b_assoc_buffers.prev ffff880221cffee8
  NILFS [nilfs_segctor_do_construct]:2336 nilfs_segctor_assign
  NILFS [nilfs_segctor_do_construct]:2367 nilfs_segctor_update_segusage
  NILFS [nilfs_segctor_do_construct]:2371 nilfs_segctor_prepare_write
  NILFS [nilfs_segctor_do_construct]:2376 nilfs_add_checksums_on_logs
  NILFS [nilfs_segctor_do_construct]:2381 nilfs_segctor_write
  NILFS [nilfs_segbuf_submit_bh]:575 bh->b_count 1, bh->b_page ffffea000709b000, page->index 0, i_ino 1033103, i_size 25165824
  NILFS [nilfs_segbuf_submit_bh]:576 segbuf->sb_segnum 6784
  NILFS [nilfs_segbuf_submit_bh]:577 bh->b_assoc_buffers.next ffff880218a0d5f8, bh->b_assoc_buffers.prev ffff880218bcdf50
  NILFS [nilfs_segbuf_submit_bio]:464 bio->bi_sector 111150080, segbuf->sb_segnum 6784, segbuf->sb_nbio 0
  [----------] ditto
  NILFS [nilfs_segbuf_submit_bio]:464 bio->bi_sector 111164416, segbuf->sb_segnum 6784, segbuf->sb_nbio 15

  [-----------------------------SEGMENT 6785-------------------------------]
  NILFS [nilfs_segctor_do_construct]:2310 nilfs_segctor_begin_construction
  NILFS [nilfs_segctor_do_construct]:2321 nilfs_segctor_collect
  NILFS [nilfs_lookup_dirty_data_buffers]:782 bh->b_count 2, bh->b_page ffffea000709b000, page->index 0, i_ino 1033103, i_size 25165824
  NILFS [nilfs_lookup_dirty_data_buffers]:783 bh->b_assoc_buffers.next ffff880219277e80, bh->b_assoc_buffers.prev ffff880221cffc88
  NILFS [nilfs_segctor_do_construct]:2367 nilfs_segctor_update_segusage
  NILFS [nilfs_segctor_do_construct]:2371 nilfs_segctor_prepare_write
  NILFS [nilfs_segctor_do_construct]:2376 nilfs_add_checksums_on_logs
  NILFS [nilfs_segctor_do_construct]:2381 nilfs_segctor_write
  NILFS [nilfs_segbuf_submit_bh]:575 bh->b_count 2, bh->b_page ffffea000709b000, page->index 0, i_ino 1033103, i_size 25165824
  NILFS [nilfs_segbuf_submit_bh]:576 segbuf->sb_segnum 6785
  NILFS [nilfs_segbuf_submit_bh]:577 bh->b_assoc_buffers.next ffff880218a0d5f8, bh->b_assoc_buffers.prev ffff880222cc7ee8
  NILFS [nilfs_segbuf_submit_bio]:464 bio->bi_sector 111165440, segbuf->sb_segnum 6785, segbuf->sb_nbio 0
  [----------] ditto
  NILFS [nilfs_segbuf_submit_bio]:464 bio->bi_sector 111177728, segbuf->sb_segnum 6785, segbuf->sb_nbio 12

  NILFS [nilfs_segctor_do_construct]:2399 nilfs_segctor_wait
  NILFS [nilfs_segbuf_wait]:676 segbuf->sb_segnum 6783
  NILFS [nilfs_segbuf_wait]:676 segbuf->sb_segnum 6784
  NILFS [nilfs_segbuf_wait]:676 segbuf->sb_segnum 6785

  NILFS [nilfs_segctor_complete_write]:2100 bh->b_count 0, bh->b_blocknr 13895680, bh->b_size 13897727, bh->b_page 0000000000001a82

  BUG: unable to handle kernel paging request at 0000000000001a82
  IP: [<ffffffffa024d0f2>] nilfs_end_page_io+0x12/0xd0 [nilfs2]

Usually, for every segment we collect dirty files in list.  Then, dirty
blocks are gathered for every dirty file, prepared for write and
submitted by means of nilfs_segbuf_submit_bh() call.  Finally, it takes
place complete write phase after calling nilfs_end_bio_write() on the
block layer.  Buffers/pages are marked as not dirty on final phase and
processed files removed from the list of dirty files.

It is possible to see that we had three prepare_write and submit_bio
phases before segbuf_wait and complete_write phase.  Moreover, segments
compete between each other for dirty blocks because on every iteration
of segments processing dirty buffer_heads are added in several lists of
payload_buffers:

  [SEGMENT 6784]: bh->b_assoc_buffers.next ffff880218a0d5f8, bh->b_assoc_buffers.prev ffff880218bcdf50
  [SEGMENT 6785]: bh->b_assoc_buffers.next ffff880218a0d5f8, bh->b_assoc_buffers.prev ffff880222cc7ee8

The next pointer is the same but prev pointer has changed.  It means
that buffer_head has next pointer from one list but prev pointer from
another.  Such modification can be made several times.  And, finally, it
can be resulted in various issues: (1) segctor hanging, (2) segctor
crashing, (3) file system metadata corruption.

FIX:
This patch adds:

(1) setting of BH_Async_Write flag in nilfs_segctor_prepare_write()
    for every proccessed dirty block;

(2) checking of BH_Async_Write flag in
    nilfs_lookup_dirty_data_buffers() and
    nilfs_lookup_dirty_node_buffers();

(3) clearing of BH_Async_Write flag in nilfs_segctor_complete_write(),
    nilfs_abort_logs(), nilfs_forget_buffer(), nilfs_clear_dirty_page().
Reported-by: NJerome Poulin <jeromepoulin@gmail.com>
Reported-by: NAnton Eliasson <devel@antoneliasson.se>
Cc: Paul Fertser <fercerpav@gmail.com>
Cc: ARAI Shun-ichi <hermes@ceres.dti.ne.jp>
Cc: Piotr Szymaniak <szarpaj@grubelek.pl>
Cc: Juan Barry Manuel Canham <Linux@riotingpacifist.net>
Cc: Zahid Chowdhury <zahid.chowdhury@starsolutions.com>
Cc: Elmer Zhang <freeboy6716@gmail.com>
Cc: Kenneth Langga <klangga@gmail.com>
Signed-off-by: NVyacheslav Dubeyko <slava@dubeyko.com>
Acked-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Han Pingtian found a typo in Documentation/kernel-parameters.txt about
"kernelcore=", that "kernelcore" should be replaced with "Movable" here.
Signed-off-by: NWeiping Pan <wpan@redhat.com>
Acked-by: NMel Gorman <mgorman@suse.de>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The "force" parameter in __blk_queue_bounce was being ignored, which
means that stable page snapshots are not always happening (on ext3).
This of course leads to DIF disks reporting checksum errors, so fix this
regression.

The regression was introduced in commit 6bc454d1 ("bounce: Refactor
__blk_queue_bounce to not use bi_io_vec")
Reported-by: NMel Gorman <mgorman@suse.de>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: <stable@vger.kernel.org>	[3.10+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If /proc/sys/kernel/core_pattern contains only "|", a NULL pointer
dereference happens upon core dump because argv_split("") returns
argv[0] == NULL.

This bug was once fixed by commit 264b83c0 ("usermodehelper: check
subprocess_info->path != NULL") but was by error reintroduced by commit
7f57cfa4 ("usermodehelper: kill the sub_info->path[0] check").

This bug seems to exist since 2.6.19 (the version which core dump to
pipe was added).  Depending on kernel version and config, some side
effect might happen immediately after this oops (e.g.  kernel panic with
2.6.32-358.18.1.el6).
Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The proc interface is not aware of sem_lock(), it instead calls
ipc_lock_object() directly.  This means that simple semop() operations
can run in parallel with the proc interface.  Right now, this is
uncritical, because the implementation doesn't do anything that requires
a proper synchronization.

But it is dangerous and therefore should be fixed.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Operations that need access to the whole array must guarantee that there
are no simple operations ongoing.  Right now this is achieved by
spin_unlock_wait(sem->lock) on all semaphores.

If complex_count is nonzero, then this spin_unlock_wait() is not
necessary, because it was already performed in the past by the thread
that increased complex_count and even though sem_perm.lock was dropped
inbetween, no simple operation could have started, because simple
operations cannot start when complex_count is non-zero.
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Cc: Mike Galbraith <bitbucket@online.de>
Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: NDavidlohr Bueso <davidlohr@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The exclusion of complex operations in sem_lock() is insufficient: after
acquiring the per-semaphore lock, a simple op must first check that
sem_perm.lock is not locked and only after that test check
complex_count.  The current code does it the other way around - and that
creates a race.  Details are below.

The patch is a complete rewrite of sem_lock(), based in part on the code
from Mike Galbraith.  It removes all gotos and all loops and thus the
risk of livelocks.

I have tested the patch (together with the next one) on my i3 laptop and
it didn't cause any problems.

The bug is probably also present in 3.10 and 3.11, but for these kernels
it might be simpler just to move the test of sma->complex_count after
the spin_is_locked() test.

Details of the bug:

Assume:
 - sma->complex_count = 0.
 - Thread 1: semtimedop(complex op that must sleep)
 - Thread 2: semtimedop(simple op).

Pseudo-Trace:

Thread 1: sem_lock(): acquire sem_perm.lock
Thread 1: sem_lock(): check for ongoing simple ops
			Nothing ongoing, thread 2 is still before sem_lock().
Thread 1: try_atomic_semop()
	<<< preempted.

Thread 2: sem_lock():
        static inline int sem_lock(struct sem_array *sma, struct sembuf *sops,
                                      int nsops)
        {
                int locknum;
         again:
                if (nsops == 1 && !sma->complex_count) {
                        struct sem *sem = sma->sem_base + sops->sem_num;

                        /* Lock just the semaphore we are interested in. */
                        spin_lock(&sem->lock);

                        /*
                         * If sma->complex_count was set while we were spinning,
                         * we may need to look at things we did not lock here.
                         */
                        if (unlikely(sma->complex_count)) {
                                spin_unlock(&sem->lock);
                                goto lock_array;
                        }
        <<<<<<<<<
	<<< complex_count is still 0.
	<<<
        <<< Here it is preempted
        <<<<<<<<<

Thread 1: try_atomic_semop() returns, notices that it must sleep.
Thread 1: increases sma->complex_count.
Thread 1: drops sem_perm.lock
Thread 2:
                /*
                 * Another process is holding the global lock on the
                 * sem_array; we cannot enter our critical section,
                 * but have to wait for the global lock to be released.
                 */
                if (unlikely(spin_is_locked(&sma->sem_perm.lock))) {
                        spin_unlock(&sem->lock);
                        spin_unlock_wait(&sma->sem_perm.lock);
                        goto again;
                }
	<<< sem_perm.lock already dropped, thus no "goto again;"

                locknum = sops->sem_num;
Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
Cc: Mike Galbraith <bitbucket@online.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: <stable@vger.kernel.org>	[3.10+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We've been getting warnings about an excessive amount of time spent
allocating pages for migration during memory compaction without
scheduling.  isolate_freepages_block() already periodically checks for
contended locks or the need to schedule, but isolate_freepages() never
does.

When a zone is massively long and no suitable targets can be found, this
iteration can be quite expensive without ever doing cond_resched().

Check periodically for the need to reschedule while the compaction free
scanner iterates.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Reviewed-by: NRik van Riel <riel@redhat.com>
Reviewed-by: NWanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: NMel Gorman <mgorman@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A high setting of max_map_count, and a process core-dumping with a large
enough vm_map_count could result in an NT_FILE note not being written,
and the kernel crashing immediately later because it has assumed
otherwise.

Reproduction of the oops-causing bug described here:

    https://lkml.org/lkml/2013/8/30/50

Rge ussue originated in commit 2aa362c4 ("coredump: extend core dump
note section to contain file names of mapped file") from Oct 4, 2012.

This patch make that section optional in that case.  fill_files_note()
should signify the error, and also let the info struct in
elf_core_dump() be zero-initialized so that we can check for the
optionally written note.

[akpm@linux-foundation.org: avoid abusing E2BIG, remove a couple of not-really-needed local variables]
[akpm@linux-foundation.org: fix sparse warning]
Signed-off-by: NDan Aloni <alonid@stratoscale.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Reported-by: NMartin MOKREJS <mmokrejs@gmail.com>
Tested-by: NMartin MOKREJS <mmokrejs@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This reverts commit cea27eb2 ("mm/memory-hotplug: fix lowmem count
overflow when offline pages").

The fixed bug by commit cea27eb2 was fixed to another way by commit
3dcc0571 ("mm: correctly update zone->managed_pages").  That commit
enhances memory_hotplug.c to adjust totalhigh_pages when hot-removing
memory, for details please refer to:

  http://marc.info/?l=linux-mm&m=136957578620221&w=2

As a result, commit cea27eb2 currently causes duplicated decreasing
of totalhigh_pages, thus the revert.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Reviewed-by: NWanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull AVR32 fixes from Hans-Christian Egtvedt.

Fix build warnings and use the Kbuild infrastructure for generic headers
rather than doing it by hand.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/egtvedt/linux-avr32:
  avr32: cast syscall_return to silence compiler warning
  avr32: fix clockevents kernel warning
  avr32: use Kbuild infrastructure to handle the asm-generic headers

Pull S+core fixes from Lennox Wu:
 "These updates include updating information of maintainers, fix some
  trivial errors, and add a necessary function for supporting ipv6"

* tag 'for-linus-20130929' of git://github.com/sctscore/official-linux:
  Score: Update the information of Score maintaners
  Score: Modify the Makefile of Score, remove -mlong-calls for compiling
  Score: Implement the function csum_ipv6_magic
  Score: The commit is for compiling successfully

Pull ARC Fixes from Vineet Gupta:
 - Handle unaligned access in zero delay loops
 - spinlock livelock fix for SMP systemC model
 - fix 32bit overflow in access_ok
 - better setup of clockevents

* tag 'arc-fixes-for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: Use clockevents_config_and_register over clockevents_register_device
  ARC: Workaround spinlock livelock in SMP SystemC simulation
  ARC: Fix 32-bit wrap around in access_ok()
  ARC: Handle zero-overhead-loop in unaligned access handler

The patch fixes the following compiler warning:
    CC      arch/avr32/kernel/process.o
  arch/avr32/kernel/process.c: In function 'copy_thread':
  arch/avr32/kernel/process.c:292: warning: assignment makes integer \
  from pointer without a cast
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Acked-by: NHans-Christian Egtvedt <egtvedt@samfundet.no>

Since commit 01426478
(avr32: Use generic idle loop) the kernel throws the
following warning on avr32:

  WARNING: at 900322e4 [verbose debug info unavailable]
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 3.12.0-rc2 #117
  task: 901c3ecc ti: 901c0000 task.ti: 901c0000
  PC is at cpu_idle_poll_ctrl+0x1c/0x38
  LR is at comparator_mode+0x3e/0x40
  pc : [<900322e4>]    lr : [<90014882>]    Not tainted
  sp : 901c1f74  r12: 00000000  r11: 901c74a0
  r10: 901d2510  r9 : 00000001  r8 : 901db4de
  r7 : 901c74a0  r6 : 00000001  r5 : 00410020  r4 : 901db574
  r3 : 00410024  r2 : 90206fe0  r1 : 00000000  r0 : 007f0000
  Flags: qvnzc
  Mode bits: hjmde....G
  CPU Mode: Supervisor
  Call trace:
   [<90039ede>] clockevents_set_mode+0x16/0x2e
   [<90039f00>] clockevents_shutdown+0xa/0x1e
   [<9003a078>] clockevents_exchange_device+0x58/0x70
   [<9003a78c>] tick_check_new_device+0x38/0x54
   [<9003a1a2>] clockevents_register_device+0x32/0x90
   [<900035c4>] time_init+0xa8/0x108
   [<90000520>] start_kernel+0x128/0x23c

When the 'avr32_comparator' clockevent device is registered,
the clockevent core sets the mode of that clockevent device
to CLOCK_EVT_MODE_SHUTDOWN. Due to this, the 'comparator_mode'
function calls the 'cpu_idle_poll_ctrl' to disables idle poll.
This results in the aforementioned warning because the polling
is not enabled yet.

Change the code to only disable idle poll if it is enabled by
the same function to avoid the warning.

Cc: stable@vger.kernel.org
Signed-off-by: NGabor Juhos <juhosg@openwrt.org>
Acked-by: NHans-Christian Egtvedt <egtvedt@samfundet.no>

Use kbuild to add asm-generic headers that do nothing, also remove the arch
specific wrapper headers.

This only affects headers that do nothing but include the generic
equivalent. It does not touch any header that does a little more.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NHans-Christian Egtvedt <egtvedt@samfundet.no>

Pull USB fixes from Greg KH:
 "Here are a number of USB driver fixes for 3.12-rc3.

  These are all for host controller issues that have been reported, and
  there's a fix for an annoying error message that gets printed every
  time you remove a USB 3 device from the system that's been bugging me
  for a while"

* tag 'usb-3.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: dwc3: add support for Merrifield
  USB: fsl/ehci: fix failure of checking PHY_CLK_VALID during reinitialization
  USB: Fix breakage in ffs_fs_mount()
  fsl/usb: Resolve PHY_CLK_VLD instability issue for ULPI phy
  usb/core/devio.c: Don't reject control message to endpoint with wrong direction bit
  usb: chipidea: USB_CHIPIDEA should depend on HAS_DMA
  usb: chipidea: udc: free pending TD at removal procedure
  usb: chipidea: imx: Add usb_phy_shutdown at probe's error path
  usb: chipidea: Fix memleak for ci->hw_bank.regmap when removal
  usb: chipidea: udc: fix the oops after rmmod gadget
  USB: fix PM config symbol in uhci-hcd, ehci-hcd, and xhci-hcd
  USB: OHCI: accept very late isochronous URBs
  USB: UHCI: accept very late isochronous URBs
  USB: iMX21: accept very late isochronous URBs
  usbcore: check usb device's state before sending a Set SEL control transfer
  xhci: Fix race between ep halt and URB cancellation
  usb: Fix xHCI host issues on remote wakeup.
  xhci: Ensure a command structure points to the correct trb on the command ring
  xhci: Fix oops happening after address device timeout

Pull tty/serial fixes from Greg KH:
 "Here are some serial at tty driver fixes for 3.12-rc3

  The serial driver fixes some kref leaks, documentation is moved to the
  proper places, and the tty and n_tty fixes resolve some reported
  regressions.  There is still one outstanding tty regression fix that
  isn't in here yet, as I want to test it out some more, it will be sent
  for 3.12-rc4 if it checks out"

* tag 'tty-3.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: ar933x_uart: move devicetree binding documentation
  tty: Fix SIGTTOU not sent with tcflush()
  n_tty: Fix EOF push index when termios changes
  serial: pch_uart: remove unnecessary tty_port_tty_get
  serial: pch_uart: fix tty-kref leak in dma-rx path
  serial: pch_uart: fix tty-kref leak in rx-error path
  serial: tegra: fix tty-kref leak

Pull staging fixes from Greg KH:
 "Here are some staging driver fixes, MAINTAINER updates, and a new
  device id.  All of these have been in the linux-next tree, and are
  pretty simple patches"

* tag 'staging-3.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: r8188eu: Add new device ID
  staging: imx-drm: Fix probe failure
  staging: vt6656: [BUG] iwctl_siwencodeext return if device not open
  staging: vt6656: [BUG] main_usb.c oops on device_close move flag earlier.
  staging: vt6656: rxtx.c [BUG] s_vGetFreeContext dead lock on null apTD.
  Staging: rtl8192u: r819xU_cmdpkt: checking NULL value after doing dev_alloc_skb
  staging: usbip: Orphan usbip
  staging: r8188eu: Add files for new drive: Cocci spatch "noderef"
  staging: r8188eu: Cocci spatch "noderef"
  staging: octeon-usb: Cocci spatch "noderef"
  staging: r8188eu: Add files for new drive: Cocci spatch "noderef"
  MAINTAINERS: staging: dgnc and dgap drivers: add maintainer
  staging: lustre: Cocci spatch "noderef"

Merge tag 'driver-core-3.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core / sysfs fixes from Greg KH:
 "Here are 2 fixes for 3.12-rc3.  One fixes a sysfs problem with
  mounting caused by 3.12-rc1, and the other is a bug reported by the
  chromeos developers with the driver core.

  Both have been in linux-next for a bit"

* tag 'driver-core-3.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  driver core : Fix use after free of dev->parent in device_shutdown
  sysfs: Allow mounting without CONFIG_NET

Pull char/misc driver fixes from Greg KH:
 "Here are some HyperV and MEI driver fixes for 3.12-rc3.  They resolve
  some issues that people have been reporting for them"

* tag 'char-misc-3.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  Drivers: hv: vmbus: Terminate vmbus version negotiation on timeout
  Drivers: hv: util: Correctly support ws2008R2 and earlier
  mei: cancel stall timers in mei_reset
  mei: bus: stop wait for read during cl state transition
  mei: make me client counters less error prone

Pull perf revert from Ingo Molnar:
 "This fixes the 'perf top' regression Markus Trippelsdorf reported"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "perf symbols: Demangle cloned functions"

Pull drm fixes from Dave Airlie:
 "Nothing too major, radeon still has some dpm changes for off by
  default.

  Radeon, intel, msm:
   - radeon: a few more dpm fixes (still off by default), uvd fixes
   - i915: runtime warn backtrace and regression fix
   - msm: iommu changes fallout"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (27 commits)
  drm/msm: use drm_gem_dumb_destroy helper
  drm/msm: deal with mach/iommu.h removal
  drm/msm: Remove iommu include from mdp4_kms.c
  drm/msm: Odd PTR_ERR usage
  drm/i915: Fix up usage of SHRINK_STOP
  drm/radeon: fix hdmi audio on DCE3.0/3.1 asics
  drm/i915: preserve pipe A quirk in i9xx_set_pipeconf
  drm/i915/tv: clear adjusted_mode.flags
  drm/i915/dp: increase i2c-over-aux retry interval on AUX DEFER
  drm/radeon/cik: fix overflow in vram fetch
  drm/radeon: add missing hdmi callbacks for rv6xx
  drm/i915: Use a temporary va_list for two-pass string handling
  drm/radeon/uvd: lower msg&fb buffer requirements on UVD3
  drm/radeon: disable tests/benchmarks if accel is disabled
  drm/radeon: don't set default clocks for SI when DPM is disabled
  drm/radeon/dpm/ci: filter clocks based on voltage/clk dep tables
  drm/radeon/dpm/si: filter clocks based on voltage/clk dep tables
  drm/radeon/dpm/ni: filter clocks based on voltage/clk dep tables
  drm/radeon/dpm/btc: filter clocks based on voltage/clk dep tables
  drm/radeon/dpm: fetch the max clk from voltage dep tables helper
  ...

This reverts commit de95ab53.

Markus Trippelsdorf reported that this commit broke 'perf top':

 > I just see a gray screen with no text at all. Sometimes the
 > following error messages are printed:
 >
 >  *** Error in `perf': invalid fastbin entry (free): 0x00000000029b18c0
 >  ***
 >  *** Error in `perf': malloc(): memory corruption (fast): 0x0000000000ee0b10 ***

While this code is fixable, the commit itself fails on several levels:

 - it should have been a separate helper function
 - why the heck does it do strchr() twice
 - it casts a const char * over into char *
 - sloppy style
 - it's not even a regression fix!

So lets revert it and re-try the patch in v3.13.
Reported-by: NMarkus Trippelsdorf <markus@trippelsdorf.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

A small fix + deal with fallout of iommu changes + use new
drm_gem_dumb_destroy helper.

* 'msm-fixes-3.12-rc2' of git://people.freedesktop.org/~robclark/linux:
  drm/msm: use drm_gem_dumb_destroy helper
  drm/msm: deal with mach/iommu.h removal
  drm/msm: Remove iommu include from mdp4_kms.c
  drm/msm: Odd PTR_ERR usage

Merge branches 'sched-urgent-for-linus', 'timers-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler, timer and x86 fixes from Ingo Molnar:
 - A context tracking ARM build and functional fix
 - A handful of ARM clocksource/clockevent driver fixes
 - An AMD microcode patch level sysfs reporting fixlet

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arm: Fix build error with context tracking calls

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource: em_sti: Set cpu_possible_mask to fix SMP broadcast
  clocksource: of: Respect device tree node status
  clocksource: exynos_mct: Set IRQ affinity when the CPU goes online
  arm: clocksource: mvebu: Use the main timer as clock source from DT

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/microcode/AMD: Fix patch level reporting for family 15h

Pull perf fixes from Ingo Molnar:
 "A couple of tooling fixlets and a PMU detection printout fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86: Fix PMU detection printout when no PMU is detected
  perf symbols: Demangle cloned functions
  perf machine: Fix path unpopulated in machine__create_modules()
  perf tools: Explicitly add libdl dependency
  perf probe: Fix probing symbols with optimization suffix
  perf trace: Add mmap2 handler
  perf kmem: Make it work again on non NUMA machines

Pull xfs bugfixes from Ben Myers:
 - fix for directory node collapse regression
 - fix for recovery over stale on disk structures
 - fix for eofblocks ioctl
 - fix asserts in xfs_inode_free
 - lock the ail before removing an item from it

* tag 'xfs-for-linus-v3.12-rc3' of git://oss.sgi.com/xfs/xfs:
  xfs: fix node forward in xfs_node_toosmall
  xfs: log recovery lsn ordering needs uuid check
  xfs: fix XFS_IOC_FREE_EOFBLOCKS definition
  xfs: asserting lock not held during freeing not valid
  xfs: lock the AIL before removing the buffer item

Pull i2c fixes from Wolfram Sang:
 "Some driver bugfixes for the I2C subsystem"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: ismt: initialize DMA buffer
  i2c: designware: 10-bit addressing mode enabling if I2C_DYNAMIC_TAR_UPDATE is set
  i2c: mv64xxx: Do not use writel_relaxed()
  i2c: mv64xxx: Fix some build warnings
  i2c: s3c2410: fix clk_disable/clk_unprepare WARNings

Pull ACPI and power management fixes from Rafael Wysocki:
 "These fix one recent cpufreq regression, a few older bugs that may
  harm users and a kerneldoc typo.

  Specifics:

   1) After the recent locking changes in the cpufreq core it is
      possible to trigger BUG_ON(!policy) in lock_policy_rwsem_read() if
      cpufreq_get() is called before registering a cpufreq driver.  Fix
      from Viresh Kumar.

   2) If intel_pstate has been loaded already, it doesn't make sense to
      do anything in acpi_cpufreq_init() and moreover doing something in
      there in that case may be harmful, so make that function return
      immediately if another cpufreq driver is already present.  From
      Yinghai Lu.

   3) The ACPI IPMI driver sometimes attempts to acquire a mutex from
      interrupt context, which can be avoided by replacing that mutex
      with a spinlock.  From Lv Zheng.

   4) A NULL pointer may be dereferenced by the exynos5440 cpufreq
      driver if a memory allocation made by it fails.  Fix from Sachin
      Kamat.

   5) Hanjun Guo's commit fixes a typo in the kerneldoc comment
      documenting acpi_bus_unregister_driver()"

* tag 'pm+acpi-3.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / scan: fix typo in comments of acpi_bus_unregister_driver()
  cpufreq: exynos5440: Fix potential NULL pointer dereference
  cpufreq: check cpufreq driver is valid and cpufreq isn't disabled in cpufreq_get()
  acpi-cpufreq: skip loading acpi_cpufreq after intel_pstate
  ACPI / IPMI: Fix atomic context requirement of ipmi_msg_handler()

Ben Herrenschmidt found that commit 928bea96 ("PCI: Delay enabling
bridges until they're needed") breaks PCI in some powerpc environments.

The reason is that the PCIe port driver will call pci_enable_device() on
the bridge, so the device is enabled, but skips pci_set_master because
pcie_port_auto and no acpi on powerpc.

Because of that, pci_enable_bridge() later on (called as a result of the
child device driver doing pci_enable_device) will see the bridge as
already enabled and will not call pci_set_master() on it.

Fixed by add checking in pci_enable_bridge, and call pci_set_master
if driver skip that.

That will make the code more robot and wade off problem for missing
pci_set_master in drivers.
Reported-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull s390 lockref enablement from Heiko Carstens:
 "Enabling the new lockless lockref variant on s390 would have been
  trivial until Tony Luck added a cpu_relax() call into the
  CMPXCHG_LOOP(), with commit d472d9d9 ("lockref: Relax in cmpxchg
  loop")

  As already mentioned cpu_relax() is very expensive on s390 since it
  yields() the current virtual cpu.  So we are talking of several
  thousand cycles.  Considering this enabling the lockless lockref
  variant would contradict the intention of the new semantics.  And also
  some quick measurements show performance regressions of 50% and more.

  Simply removing the cpu_relax() call again seems also not very
  desireable since Waiman Long reported that for some workloads the call
  improved performance by 5%."

* 'lockref' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390: enable ARCH_USE_CMPXCHG_LOCKREF
  lockref: use arch_mutex_cpu_relax() in CMPXCHG_LOOP()
  mutex: replace CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX with simple ifdef