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David Rientjes 668f9abbd4 mm: close PageTail race 
Commit bf6bddf192 ("mm: introduce compaction and migration for
ballooned pages") introduces page_count(page) into memory compaction
which dereferences page->first_page if PageTail(page).

This results in a very rare NULL pointer dereference on the
aforementioned page_count(page).  Indeed, anything that does
compound_head(), including page_count() is susceptible to racing with
prep_compound_page() and seeing a NULL or dangling page->first_page
pointer.

This patch uses Andrea's implementation of compound_trans_head() that
deals with such a race and makes it the default compound_head()
implementation.  This includes a read memory barrier that ensures that
if PageTail(head) is true that we return a head page that is neither
NULL nor dangling.  The patch then adds a store memory barrier to
prep_compound_page() to ensure page->first_page is set.

This is the safest way to ensure we see the head page that we are
expecting, PageTail(page) is already in the unlikely() path and the
memory barriers are unfortunately required.

Hugetlbfs is the exception, we don't enforce a store memory barrier
during init since no race is possible.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Holger Kiehl <Holger.Kiehl@dwd.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2014-03-04 07:55:47 -08:00
..
9p Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-01-28 08:38:04 -08:00
adfs adfs: delayed freeing of sbi 2013-10-24 23:43:27 -04:00
affs affs: use ->kill_sb() to simplify ->put_super() and failure exits of ->mount() 2014-01-25 03:13:01 -05:00
afs afs: proc cells and rootcell are writeable 2014-02-01 10:59:39 -08:00
autofs4 autofs: fix symlinks aren't checked for expiry 2014-01-23 16:36:59 -08:00
befs befs: iget_locked() doesn't return an ERR_PTR 2014-01-25 03:14:38 -05:00
bfs
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btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2014-02-16 11:05:27 -08:00
cachefiles Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-11-13 15:34:18 +09:00
ceph ceph: fix __dcache_readdir() 2014-02-17 12:37:13 -08:00
cifs Merge branch 'for-linus' of git://git.samba.org/sfrench/cifs-2.6 2014-02-17 13:50:11 -08:00
coda coda_revalidate_inode(): switch to passing inode... 2013-11-09 00:16:21 -05:00
configfs configfs: fix race between dentry put and lookup 2013-11-21 16:42:27 -08:00
cramfs cramfs: take headers to fs/cramfs 2014-01-25 03:13:02 -05:00
debugfs debugfs: use list_next_entry() in debugfs_remove_recursive() 2013-11-13 12:09:24 +09:00
devpts devpts: plug the memory leak in kill_sb 2013-11-13 12:09:36 +09:00
dlm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-01-25 11:17:34 -08:00
ecryptfs ecryptfs: fix failure handling in ->readlink() 2014-01-25 03:13:00 -05:00
efivarfs consolidate simple ->d_delete() instances 2013-11-15 22:04:17 -05:00
efs efs: get rid of ->put_super() 2014-01-25 03:13:02 -05:00
exofs exofs: Print less in r4w 2014-01-23 18:54:14 +02:00
exportfs exportfs: fix quadratic behavior in filehandle lookup 2013-11-09 00:16:38 -05:00
ext2 ext2/3/4: use generic posix ACL infrastructure 2014-01-25 23:58:19 -05:00
ext3 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-01-28 08:38:04 -08:00
ext4 ext4: don't leave i_crtime.tv_sec uninitialized 2014-02-16 19:29:32 -05:00
f2fs Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block 2014-01-30 11:19:05 -08:00
fat fat: rcu-delay unloading nls and freeing sbi 2013-10-24 23:43:28 -04:00
freevxfs
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fscache FS-Cache: Handle removal of unadded object to the fscache_object_list rb tree 2014-02-17 13:47:35 -08:00
fuse Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-01-28 08:38:04 -08:00
gfs2 Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block 2014-01-30 11:19:05 -08:00
hfs fs/hfs/btree.h: remove duplicate defines 2013-11-13 12:09:32 +09:00
hfsplus Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-02-01 10:43:45 -08:00
hostfs um: hostfs: make functions static 2014-01-26 11:51:09 +01:00
hpfs hpfs: optimize quad buffer loading 2014-02-02 16:24:07 -08:00
hppfs
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hugetlbfs
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isofs isofs: don't pass dentry to isofs_hash{i,}_common() 2013-10-24 23:34:59 -04:00
jbd jbd: Revise KERN_EMERG error messages 2013-12-04 12:27:46 +01:00
jbd2 jbd2: fix use after free in jbd2_journal_start_reserved() 2014-02-17 20:33:01 -05:00
jffs2 MTD updates for 3.14: 2014-01-28 18:56:37 -08:00
jfs jfs: set i_ctime when setting ACL 2014-02-13 15:56:05 -06:00
kernfs sysfs: fix namespace refcnt leak 2014-02-25 07:37:52 -08:00
lockd lockd: send correct lock when granting a delayed lock. 2014-02-13 14:55:02 -05:00
logfs Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block 2014-01-30 11:19:05 -08:00
minix
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ncpfs ncpfs: rcu-delay unload_nls() and freeing ncp_server 2013-10-24 23:43:28 -04:00
nfs Merge branch 'for-3.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2014-02-20 12:01:09 -08:00
nfs_common
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nfsd nfsd4: fix acl buffer overrun 2014-02-11 13:48:11 -05:00
nilfs2 Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block 2014-01-30 11:19:05 -08:00
nls nls: have register_nls() set ->owner 2014-01-25 03:14:05 -05:00
notify fsnotify: Allocate overflow events with proper type 2014-02-25 11:18:06 +01:00
ntfs fix O_SYNC|O_APPEND syncing the wrong range on write() 2014-02-09 15:18:09 -05:00
ocfs2 ocfs2: check existence of old dentry in ocfs2_link() 2014-02-10 16:01:43 -08:00
omfs
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openpromfs
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proc mm: close PageTail race 2014-03-04 07:55:47 -08:00
pstore pstore: Don't allow high traffic options on fragile devices 2013-12-20 13:12:01 -08:00
qnx4 qnx4: clean qnx4_fill_super() up 2014-01-25 03:13:03 -05:00
qnx6
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quota quota: Fix race between dqput() and dquot_scan_active() 2014-02-20 21:57:04 +01:00
ramfs fs/ramfs: move ramfs_aops to inode.c 2014-01-23 16:36:58 -08:00
reiserfs reiserfs: fix utterly brain-damaged indentation. 2014-02-17 13:46:33 -08:00
romfs romfs: fix returm err while getting inode in fill_super 2014-01-23 16:37:04 -08:00
squashfs Squashfs: fix failure to unlock pages on decompress error 2013-11-24 01:02:50 +00:00
sysfs sysfs: fix namespace refcnt leak 2014-02-25 07:37:52 -08:00
sysv
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ubifs fs/ubifs: use rbtree postorder iteration helper instead of opencoding 2014-01-23 16:37:03 -08:00
udf udf: Fix data corruption on file type conversion 2014-02-20 21:56:00 +01:00
ufs
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xfs Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2014-02-27 10:37:22 -08:00
Kconfig fs: remove generic_acl 2014-01-26 08:26:40 -05:00
Kconfig.binfmt
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Makefile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-01-28 08:38:04 -08:00
aio.c Merge git://git.kvack.org/~bcrl/aio-next 2013-12-22 11:03:49 -08:00
anon_inodes.c ... and kill anon_inode_getfile_private() 2013-11-09 00:16:28 -05:00
attr.c fs: fix iversion handling 2013-12-05 16:36:21 -06:00
bad_inode.c
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binfmt_aout.c dump_skip(): dump_seek() replacement taking coredump_params 2013-11-09 00:16:26 -05:00
binfmt_elf.c fs: binfmt_elf: remove unused defines INTERPRETER_NONE and INTERPRETER_ELF 2014-01-23 16:36:58 -08:00
binfmt_elf_fdpic.c elf{,_fdpic} coredump: get rid of pointless if (siginfo->si_signo) 2013-11-09 00:16:30 -05:00
binfmt_em86.c file->f_op is never NULL... 2013-10-24 23:34:54 -04:00
binfmt_flat.c
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binfmt_misc.c
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binfmt_script.c
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binfmt_som.c
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bio-integrity.c fs: Mark function as static in fs/bio-integrity.c 2014-02-09 13:56:23 -07:00
bio.c block: Fix cloning of discard/write same bios 2014-02-11 08:40:45 -07:00
block_dev.c
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buffer.c mm: __set_page_dirty uses spin_lock_irqsave instead of spin_lock_irq 2014-02-06 13:48:51 -08:00
char_dev.c Merge branch 'for-3.13/core' of git://git.kernel.dk/linux-block 2013-11-14 12:08:14 +09:00
compat.c
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compat_binfmt_elf.c
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compat_ioctl.c fs/compat_ioctl.c: fix an underflow issue (harmless) 2014-01-21 16:19:42 -08:00
coredump.c coredump: make __get_dumpable/get_dumpable inline, kill fs/coredump.h 2014-01-23 16:37:01 -08:00
dcache.c __dentry_path() fixes 2014-01-26 12:37:55 -05:00
dcookies.c fs/compat: fix lookup_dcookie() parameter handling 2014-01-29 16:22:40 -08:00
direct-io.c block: Abstract out bvec iterator 2013-11-23 22:33:47 -08:00
drop_caches.c
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eventfd.c eventfd_ctx_fdget(): use fdget() instead of fget() 2014-01-25 03:13:04 -05:00
eventpoll.c epoll: do not take the nested ep->mtx on EPOLL_CTL_DEL 2014-01-02 14:40:30 -08:00
exec.c execve: use 'struct filename *' for executable name passing 2014-02-05 12:54:53 -08:00
fcntl.c file->f_op is never NULL... 2013-10-24 23:34:54 -04:00
fhandle.c
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file.c fs/file.c:fdtable: avoid triggering OOMs from alloc_fdmem 2014-02-10 16:01:41 -08:00
file_table.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-11-13 15:34:18 +09:00
filesystems.c
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fs-writeback.c Revert "writeback: do not sync data dirtied after sync start" 2014-02-22 02:02:28 +01:00
fs_struct.c seqcount: Add lockdep functionality to seqcount/seqlock structures 2013-11-06 12:40:26 +01:00
inode.c locks: break delegations on any attribute modification 2013-11-09 00:16:44 -05:00
internal.h get rid of s_files and files_lock 2013-11-09 00:16:20 -05:00
ioctl.c file->f_op is never NULL... 2013-10-24 23:34:54 -04:00
ioprio.c
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libfs.c consolidate simple ->d_delete() instances 2013-11-15 22:04:17 -05:00
locks.c locks: missing unlock on error in generic_add_lease() 2013-11-13 07:30:53 -05:00
mbcache.c
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mount.h vfs: Is mounted should be testing mnt_ns for NULL or error. 2014-01-26 08:26:42 -05:00
mpage.c block: Abstract out bvec iterator 2013-11-23 22:33:47 -08:00
namei.c execve: use 'struct filename *' for executable name passing 2014-02-05 12:54:53 -08:00
namespace.c Driver core / sysfs patches for 3.14-rc1 2014-01-20 15:49:44 -08:00
no-block.c
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open.c locks: break delegations on any attribute modification 2013-11-09 00:16:44 -05:00
pipe.c fs/pipe.c: skip file_update_time on frozen fs 2014-01-23 16:37:00 -08:00
pnode.c split __lookup_mnt() in two functions 2013-10-24 23:35:00 -04:00
pnode.h
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posix_acl.c fs: get_acl() must be allowed to return EOPNOTSUPP 2014-02-03 17:12:37 -05:00
proc_namespace.c fs/proc_namespace.c: simplify testing nsp and nsp->mnt_ns 2014-01-23 16:37:02 -08:00
read_write.c fs/compat: fix parameter handling for compat readv/writev syscalls 2014-01-29 16:22:39 -08:00
readdir.c file->f_op is never NULL... 2013-10-24 23:34:54 -04:00
select.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-11-13 15:34:18 +09:00
seq_file.c seq_file: always clear m->count when we free m->buf 2013-11-18 19:07:53 -08:00
signalfd.c
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splice.c fuse: fix pipe_buf_operations 2014-01-22 19:36:57 +01:00
stack.c
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stat.c vfs: split out vfs_getattr_nosec 2013-11-09 00:16:31 -05:00
statfs.c vfs: allow O_PATH file descriptors for fstatfs() 2013-10-12 13:12:31 -07:00
super.c fs/super.c: sync ro remount after blocking writers 2014-01-31 14:29:36 -05:00
sync.c Revert "writeback: do not sync data dirtied after sync start" 2014-02-22 02:02:28 +01:00
timerfd.c
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utimes.c locks: break delegations on any attribute modification 2013-11-09 00:16:44 -05:00
xattr.c
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