kernel_optimize_test/fs
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
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
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
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
configfs
cramfs cramfs: take headers to fs/cramfs 2014-01-25 03:13:02 -05:00
debugfs
devpts
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
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
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
freevxfs
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
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
hugetlbfs
isofs
jbd
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
ncpfs
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
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
openpromfs
proc mm: close PageTail race 2014-03-04 07:55:47 -08:00
pstore
qnx4 qnx4: clean qnx4_fill_super() up 2014-01-25 03:13:03 -05:00
qnx6
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
sysfs sysfs: fix namespace refcnt leak 2014-02-25 07:37:52 -08:00
sysv
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
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
aio.c
anon_inodes.c
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c
binfmt_elf.c fs: binfmt_elf: remove unused defines INTERPRETER_NONE and INTERPRETER_ELF 2014-01-23 16:36:58 -08:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c
binfmt_script.c
binfmt_som.c
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
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
compat_binfmt_elf.c
compat_ioctl.c fs/compat_ioctl.c: fix an underflow issue (harmless) 2014-01-21 16:19:42 -08:00
compat.c
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
drop_caches.c
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
fhandle.c
file_table.c
file.c fs/file.c:fdtable: avoid triggering OOMs from alloc_fdmem 2014-02-10 16:01:41 -08:00
filesystems.c
fs_struct.c
fs-writeback.c Revert "writeback: do not sync data dirtied after sync start" 2014-02-22 02:02:28 +01:00
inode.c
internal.h
ioctl.c
ioprio.c
Kconfig fs: remove generic_acl 2014-01-26 08:26:40 -05:00
Kconfig.binfmt
libfs.c
locks.c
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
mbcache.c
mount.h vfs: Is mounted should be testing mnt_ns for NULL or error. 2014-01-26 08:26:42 -05:00
mpage.c
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
open.c
pipe.c fs/pipe.c: skip file_update_time on frozen fs 2014-01-23 16:37:00 -08:00
pnode.c
pnode.h
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
select.c
seq_file.c
signalfd.c
splice.c fuse: fix pipe_buf_operations 2014-01-22 19:36:57 +01:00
stack.c
stat.c
statfs.c
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
utimes.c
xattr.c