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Mike Kravetz c86aa7bbfd hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race 
hugetlbfs page faults can race with truncate and hole punch operations.
Current code in the page fault path attempts to handle this by 'backing
out' operations if we encounter the race.  One obvious omission in the
current code is removing a page newly added to the page cache.  This is
pretty straight forward to address, but there is a more subtle and
difficult issue of backing out hugetlb reservations.  To handle this
correctly, the 'reservation state' before page allocation needs to be
noted so that it can be properly backed out.  There are four distinct
possibilities for reservation state: shared/reserved, shared/no-resv,
private/reserved and private/no-resv.  Backing out a reservation may
require memory allocation which could fail so that needs to be taken into
account as well.

Instead of writing the required complicated code for this rare occurrence,
just eliminate the race.  i_mmap_rwsem is now held in read mode for the
duration of page fault processing.  Hold i_mmap_rwsem longer in truncation
and hold punch code to cover the call to remove_inode_hugepages.

With this modification, code in remove_inode_hugepages checking for races
becomes 'dead' as it can not longer happen.  Remove the dead code and
expand comments to explain reasoning.  Similarly, checks for races with
truncation in the page fault path can be simplified and removed.

[mike.kravetz@oracle.com: incorporat suggestions from Kirill]
  Link: http://lkml.kernel.org/r/20181222223013.22193-3-mike.kravetz@oracle.com
Link: http://lkml.kernel.org/r/20181218223557.5202-3-mike.kravetz@oracle.com
Fixes: ebed4bfc8d ("hugetlb: fix absurd HugePages_Rsvd")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:52 -08:00
..
9p Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-11-01 19:58:52 -07:00
adfs adfs: use timespec64 for time conversion 2018-08-22 10:52:51 -07:00
affs affs: fix potential memory leak when parsing option 'prefix' 2018-05-28 12:36:41 +02:00
afs Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-11-30 10:47:50 -08:00
autofs Merge branch 'akpm' (patches from Andrew) 2018-08-22 12:34:08 -07:00
befs fix a series of Documentation/ broken file name references 2018-06-15 18:10:01 -03:00
bfs bfs: add sanity check at bfs_fill_super() 2018-11-03 10:09:38 -07:00
btrfs btrfs: Fix typos in comments and strings 2018-12-17 14:51:50 +01:00
cachefiles fscache, cachefiles: remove redundant variable 'cache' 2018-11-30 16:00:58 +00:00
ceph mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
cifs File locking changes for v4.21 2018-12-27 17:12:30 -08:00
coda vfs: change inode times to use struct timespec64 2018-06-05 16:57:31 -07:00
configfs configfs: fix registered group removal 2018-07-17 06:14:07 -07:00
cramfs Make the Cramfs code more robust against filesystem corruptions, 2018-10-30 12:46:25 -07:00
crypto crypto: speck - remove Speck 2018-09-04 11:35:03 +08:00
debugfs Revert "debugfs: inode: debugfs_create_dir uses mode permission from parent" 2018-06-12 20:52:16 -07:00
devpts devpts: Convert to new IDA API 2018-08-21 23:54:17 -04:00
dlm dlm: fix invalid cluster name warning 2018-12-03 15:30:24 -06:00
ecryptfs ecryptfs_rename(): verify that lower dentries are still OK after lock_rename() 2018-10-09 23:33:17 -04:00
efivarfs efivars: Call guid_parse() against guid_t type of variable 2018-07-22 14:13:44 +02:00
efs
exofs fs/exofs: only use true/false for asignment of bool type variable 2018-10-18 02:04:59 -04:00
exportfs exportfs: do not read dentry after free 2018-11-23 09:08:17 -05:00
ext2 \n 2018-12-27 17:00:35 -08:00
ext4 ext4: check for shutdown and r/o file system in ext4_write_inode() 2018-12-19 14:36:58 -05:00
f2fs mm: migrate: drop unused argument of migrate_page_move_mapping() 2018-12-28 12:11:51 -08:00
fat fat: truncate inode timestamp updates in setattr 2018-10-31 08:54:14 -07:00
freevxfs freevxfs_lookup(): use d_splice_alias() 2018-05-22 14:27:51 -04:00
fscache fscache: fix race between enablement and dropping of object 2018-11-30 15:57:31 +00:00
fuse mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
gfs2 File locking changes for v4.21 2018-12-27 17:12:30 -08:00
hfs hfs: do not free node before using 2018-11-30 14:56:14 -08:00
hfsplus hfsplus: do not free node before using 2018-11-30 14:56:14 -08:00
hostfs vfs: discard ATTR_ATTR_FLAG 2018-08-17 16:20:28 -07:00
hpfs hpfs: remove unnecessary checks on the value of r when assigning error code 2018-08-25 12:42:33 -07:00
hugetlbfs hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race 2018-12-28 12:11:52 -08:00
isofs Update email address 2018-09-29 22:47:48 -04:00
jbd2 jbd2: clean up indentation issue, replace spaces with tab 2018-12-04 00:20:10 -05:00
jffs2 jffs2: Fix use of uninitialized delayed_work, lockdep breakage 2018-12-02 09:20:34 +01:00
jfs jfs: remove redundant dquot_initialize() in jfs_evict_inode() 2018-09-20 09:28:49 -05:00
kernfs mm: zero-seek shrinkers 2018-10-26 16:26:33 -07:00
lockd fs/locks: merge posix_unblock_lock() and locks_delete_block() 2018-12-07 06:50:56 -05:00
minix minix_lookup: use d_splice_alias() 2018-05-22 14:27:52 -04:00
nfs mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
nfs_common net: Drop pernet_operations::async 2018-03-27 13:18:09 -04:00
nfsd mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
nilfs2 nilfs2: Use xa_erase_irq 2018-11-05 14:57:05 -05:00
nls
notify fanotify: Use inode_is_open_for_write 2018-12-11 10:55:45 +01:00
ntfs mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
ocfs2 ocfs2: don't clear bh uptodate for block read 2018-12-28 12:11:46 -08:00
omfs omfs_lookup(): report IO errors, use d_splice_alias() 2018-05-22 14:27:58 -04:00
openpromfs fs/openpromfs: Use of_node_name_eq for node name comparisons 2018-11-18 13:35:19 -08:00
orangefs Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-11-01 19:58:52 -07:00
overlayfs Revert "ovl: relax permission checking on underlying layers" 2018-12-04 11:31:30 +01:00
proc mm, proc: report PR_SET_THP_DISABLE in proc 2018-12-28 12:11:50 -08:00
pstore pstore/ram: Avoid NULL deref in ftrace merging failure path 2018-12-03 17:11:02 -08:00
qnx4 qnx4_lookup: use d_splice_alias() 2018-05-22 14:27:52 -04:00
qnx6 qnx6_lookup: switch to d_splice_alias() 2018-05-22 14:27:54 -04:00
quota quota: Lock s_umount in exclusive mode for Q_XQUOTA{ON,OFF} quotactls. 2018-12-18 18:29:15 +01:00
ramfs
reiserfs reiserfs: remove workaround code for GCC 3.x 2018-10-31 08:54:14 -07:00
romfs romfs_lookup: switch to d_splice_alias() 2018-05-22 14:27:55 -04:00
squashfs Squashfs: Compute expected length from inode size rather than block length 2018-08-02 09:34:02 -07:00
sysfs sysfs: constify sysfs create/remove files harder 2018-12-03 18:18:19 +02:00
sysv sysv: return 'err' instead of 0 in __sysv_write_inode 2018-11-10 08:02:40 -05:00
tracefs tracefs: Annotate tracefs_ops with __ro_after_init 2018-07-31 11:32:44 -04:00
ubifs mm: migrate: drop unused argument of migrate_page_move_mapping() 2018-12-28 12:11:51 -08:00
udf \n 2018-12-27 17:00:35 -08:00
ufs fs/ufs: use ktime_get_real_seconds for sb and cg timestamps 2018-08-17 16:20:27 -07:00
xfs xfs: reallocate realtime summary cache on growfs 2018-12-21 18:45:18 -08:00
aio.c mm: migrate: drop unused argument of migrate_page_move_mapping() 2018-12-28 12:11:51 -08:00
anon_inodes.c anon_inode_getfile(): switch to alloc_file_pseudo() 2018-07-12 10:04:27 -04:00
attr.c fs: Fix attr.c kernel-doc 2018-07-03 16:44:45 -04:00
bad_inode.c get rid of 'opened' argument of ->atomic_open() - part 3 2018-07-12 10:04:20 -04:00
binfmt_aout.c exec: introduce finalize_exec() before start_thread() 2018-04-11 10:28:37 -07:00
binfmt_elf_fdpic.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
binfmt_elf.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
binfmt_em86.c
binfmt_flat.c exec: introduce finalize_exec() before start_thread() 2018-04-11 10:28:37 -07:00
binfmt_misc.c turn filp_clone_open() into inline wrapper for dentry_open() 2018-07-10 23:29:03 -04:00
binfmt_script.c
block_dev.c blkdev: avoid migration stalls for blkdev pages 2018-12-28 12:11:51 -08:00
buffer.c for-linus-20181102 2018-11-02 11:25:48 -07:00
char_dev.c block, char_dev: Use correct format specifier for unsigned ints 2018-03-15 17:59:24 +01:00
compat_binfmt_elf.c y2038: globally rename compat_time to old_time32 2018-08-27 14:48:48 +02:00
compat_ioctl.c media updates for v4.20-rc1 2018-10-29 14:29:58 -07:00
compat.c ncpfs: remove compat functionality 2018-06-05 19:23:26 +02:00
coredump.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
d_path.c split d_path() and friends into a separate file 2018-03-29 15:07:46 -04:00
dax.c mm/mmu_notifier: use structure for invalidate_range_start/end calls v2 2018-12-28 12:11:50 -08:00
dcache.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
dcookies.c fs: add do_lookup_dcookie() helper; remove in-kernel call to syscall 2018-04-02 20:15:39 +02:00
direct-io.c fs: fix lost error code in dio_complete 2018-11-30 08:35:14 -07:00
drop_caches.c
eventfd.c Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLL 2018-06-28 10:40:47 -07:00
eventpoll.c fs/eventpoll.c: simplify ep_is_linked() callers 2018-08-22 10:52:49 -07:00
exec.c Revert "exec: make de_thread() freezable" 2018-12-04 16:04:20 +01:00
fcntl.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
fhandle.c
file_table.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
file.c fs/file: Replace synchronize_sched() with synchronize_rcu() 2018-11-27 09:21:39 -08:00
filesystems.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
fs_pin.c
fs_struct.c
fs-writeback.c fs: Convert writeback to XArray 2018-10-21 10:46:42 -04:00
inode.c mm: don't reclaim inodes with many attached pages 2018-11-18 10:15:09 -08:00
internal.h overlayfs update for 4.19 2018-08-21 18:19:09 -07:00
ioctl.c vfs: rework data cloning infrastructure 2018-11-02 09:33:08 -07:00
iomap.c mm: migrate: drop unused argument of migrate_page_move_mapping() 2018-12-28 12:11:51 -08:00
Kconfig autofs: remove left-over autofs4 stubs 2018-06-11 08:22:34 -07:00
Kconfig.binfmt kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
libfs.c fs, dax: prepare for dax-specific address_space_operations 2018-03-30 11:34:55 -07:00
locks.c locks: Use inode_is_open_for_write 2018-12-17 07:19:46 -05:00
Makefile autofs: remove left-over autofs4 stubs 2018-06-11 08:22:34 -07:00
mbcache.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
mount.h
mpage.c mpage: mpage_readpages() should submit IO as read-ahead 2018-08-17 16:20:29 -07:00
namei.c Revert "vfs: Allow userns root to call mknod on owned filesystems." 2018-12-22 14:18:34 -08:00
namespace.c mnt: fix __detach_mounts infinite loop 2018-11-12 01:02:34 -06:00
no-block.c
nsfs.c net: Export open_related_ns() 2018-02-15 15:34:42 -05:00
open.c overlayfs update for 4.19 2018-08-21 18:19:09 -07:00
pipe.c Merge branch 'work.open3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-08-13 19:58:36 -07:00
pnode.c
pnode.h
posix_acl.c
proc_namespace.c vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
read_write.c vfs: allow some remap flags to be passed to vfs_clone_file_range 2018-12-04 08:50:49 -08:00
readdir.c fs: add ksys_getdents64() helper; remove in-kernel calls to sys_getdents64() 2018-04-02 20:16:02 +02:00
select.c y2038: globally rename compat_time to old_time32 2018-08-27 14:48:48 +02:00
seq_file.c fs/seq_file.c: simplify seq_file iteration code and interface 2018-08-17 16:20:28 -07:00
signalfd.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
splice.c splice: don't read more than available pipe space 2018-12-04 08:50:49 -08:00
stack.c
stat.c y2038: Remove newstat family from default syscall set 2018-08-29 15:42:20 +02:00
statfs.c kernel: add kcompat_sys_{f,}statfs64() 2018-07-12 14:49:48 +01:00
super.c fsnotify: add super block object type 2018-09-03 15:14:01 +02:00
sync.c Changes for this release: 2018-04-04 12:44:02 -07:00
timerfd.c y2038: globally rename compat_time to old_time32 2018-08-27 14:48:48 +02:00
userfaultfd.c userfaultfd: clear flag if remap event not enabled 2018-12-28 12:11:51 -08:00
utimes.c y2038: utimes: Rework #ifdef guards for compat syscalls 2018-08-29 15:42:23 +02:00
xattr.c sysfs: Do not return POSIX ACL xattrs via listxattr 2018-09-18 07:30:48 -04:00