kernel_optimize_test/fs
Nadav Amit 6afd1e053d userfaultfd: prevent concurrent API initialization
[ Upstream commit 22e5fe2a2a279d9a6fcbdfb4dffe73821bef1c90 ]

userfaultfd assumes that the enabled features are set once and never
changed after UFFDIO_API ioctl succeeded.

However, currently, UFFDIO_API can be called concurrently from two
different threads, succeed on both threads and leave userfaultfd's
features in non-deterministic state.  Theoretically, other uffd operations
(ioctl's and page-faults) can be dispatched while adversely affected by
such changes of features.

Moreover, the writes to ctx->state and ctx->features are not ordered,
which can - theoretically, again - let userfaultfd_ioctl() think that
userfaultfd API completed, while the features are still not initialized.

To avoid races, it is arguably best to get rid of ctx->state.  Since there
are only 2 states, record the API initialization in ctx->features as the
uppermost bit and remove ctx->state.

Link: https://lkml.kernel.org/r/20210808020724.1022515-3-namit@vmware.com
Fixes: 9cd75c3cd4 ("userfaultfd: non-cooperative: add ability to report non-PF events from uffd descriptor")
Signed-off-by: Nadav Amit <namit@vmware.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-18 13:40:17 +02:00
..
9p new helper: inode_wrong_type() 2021-09-08 08:49:01 +02:00
adfs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
affs fs/affs: release old buffer head on error path 2021-03-04 11:38:37 +01:00
afs afs: Fix tracepoint string placement with built-in AFS 2021-07-28 14:35:41 +02:00
autofs autofs: harden ioctl table 2020-10-16 11:11:22 -07:00
befs
bfs bfs: don't use WARNING: string when it's just info. 2021-01-06 14:56:52 +01:00
btrfs btrfs: reset replace target device to allocation state on close 2021-09-18 13:40:06 +02:00
cachefiles fs/cachefiles: Remove wait_bit_key layout dependency 2021-03-30 14:32:07 +02:00
ceph ceph: fix dereference of null pointer cf 2021-09-18 13:40:06 +02:00
cifs CIFS: Fix a potencially linear read overflow 2021-09-15 09:50:43 +02:00
coda
configfs configfs: fix memleak in configfs_release_bin_file 2021-07-14 16:56:48 +02:00
cramfs
crypto fscrypt: add fscrypt_symlink_getattr() for computing st_size 2021-09-08 08:48:59 +02:00
debugfs debugfs: Return error during {full/open}_proxy_open() on rmmod 2021-09-15 09:50:37 +02:00
devpts
dlm fs: dlm: fix memory leak when fenced 2021-07-14 16:55:59 +02:00
ecryptfs Revert "ecryptfs: replace BUG_ON with error handling code" 2021-05-26 12:06:55 +02:00
efivarfs efivarfs: revert "fix memory leak in efivarfs_create()" 2020-11-25 16:55:02 +01:00
efs
erofs erofs: fix error return code in erofs_read_superblock() 2021-07-14 16:56:53 +02:00
exfat exfat: handle wrong stream entry size in exfat_readdir() 2021-07-14 16:56:52 +02:00
exportfs
ext2 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
ext4 ext4: report correct st_size for encrypted symlinks 2021-09-08 08:48:59 +02:00
f2fs f2fs: should put a page beyond EOF when preparing a write 2021-09-18 13:40:16 +02:00
fat
freevxfs
fscache fscache: Fix cookie key hashing 2021-09-18 13:40:15 +02:00
fuse fuse: flush extending writes 2021-09-15 09:50:48 +02:00
gfs2 gfs2: init system threads before freeze lock 2021-09-15 09:50:42 +02:00
hfs hfs: add lock nesting notation to hfs_find_init 2021-07-31 08:16:12 +02:00
hfsplus hfsplus: prevent corruption in shrinking truncate 2021-05-19 10:13:10 +02:00
hostfs hostfs: fix memory handling in follow_link() 2021-04-14 08:42:06 +02:00
hpfs
hugetlbfs hugetlbfs: fix mount mode command line processing 2021-07-28 14:35:46 +02:00
iomap mm/swap: consider max pages in iomap_swapfile_add_extent 2021-09-15 09:50:42 +02:00
isofs isofs: joliet: Fix iocharset=utf8 mount option 2021-09-15 09:50:25 +02:00
jbd2 ext4: fix debug format string warning 2021-05-19 10:13:19 +02:00
jffs2 jffs2: check the validity of dstlen in jffs2_zlib_compress() 2021-05-11 14:47:36 +02:00
jfs fs/jfs: Fix missing error code in lmLogInit() 2021-07-20 16:05:40 +02:00
kernfs kernfs: wire up ->splice_read and ->splice_write 2021-01-27 11:55:29 +01:00
lockd lockd: Fix invalid lockowner cast after vfs_test_lock 2021-09-15 09:50:41 +02:00
minix
nfs NFSv4/pnfs: The layout barrier indicate a minimal value for the seqid 2021-09-18 13:40:13 +02:00
nfs_common nfs_common: need lock during iterate through the list 2020-12-30 11:53:45 +01:00
nfsd nfsd4: Fix forced-expiry locking 2021-09-15 09:50:41 +02:00
nilfs2 nilfs2: fix memory leak in nilfs_sysfs_delete_device_group 2021-06-30 08:47:24 -04:00
nls
notify fanotify: fix copy_event_to_user() fid error clean up 2021-06-23 14:42:41 +02:00
ntfs ntfs: fix validity check for file name attribute 2021-07-14 16:55:38 +02:00
ocfs2 ocfs2: issue zeroout to EOF blocks 2021-08-04 12:46:40 +02:00
omfs fs: omfs: use kmemdup() rather than kmalloc+memcpy 2020-09-22 23:39:45 -04:00
openpromfs
orangefs orangefs: fix orangefs df output. 2021-07-20 16:05:48 +02:00
overlayfs new helper: inode_wrong_type() 2021-09-08 08:49:01 +02:00
proc proc: Avoid mixing integer types in mem_rw() 2021-07-28 14:35:42 +02:00
pstore mark pstore-blk as broken 2021-07-14 16:56:12 +02:00
qnx4
qnx6
quota quota: Fix memory leak when handling corrupted quota file 2021-03-04 11:37:53 +01:00
ramfs ramfs: fix nommu mmap with gaps in the page cache 2020-10-16 11:11:22 -07:00
reiserfs reiserfs: check directory items on read from disk 2021-08-12 13:22:19 +02:00
romfs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
squashfs squashfs: fix divide error in calculate_skip() 2021-05-19 10:13:10 +02:00
sysfs sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output 2020-10-02 12:02:30 +02:00
sysv
tracefs
ubifs ubifs: report correct st_size for encrypted symlinks 2021-09-08 08:48:59 +02:00
udf udf_get_extendedattr() had no boundary checks. 2021-09-15 09:50:27 +02:00
ufs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
unicode
vboxsf vboxsf: Add support for the atomic_open directory-inode op 2021-08-18 08:59:18 +02:00
verity
xfs xfs: fix return of uninitialized value in variable error 2021-05-14 09:50:34 +02:00
zonefs zonefs: fix to update .i_wr_refcnt correctly in zonefs_open_zone() 2021-03-25 09:04:05 +01:00
aio.c vfs: separate __sb_start_write into blocking and non-blocking helpers 2020-11-10 16:53:07 -08:00
anon_inodes.c
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c binfmt_elf, binfmt_elf_fdpic: use a VMA list snapshot 2020-10-16 11:11:21 -07:00
binfmt_elf.c fs: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c binfmt_misc: fix possible deadlock in bm_register_write 2021-03-17 17:06:35 +01:00
binfmt_script.c
block_dev.c block: fix a race between del_gendisk and BLKRRPART 2021-06-03 09:00:45 +02:00
buffer.c mm, memcg: rework remote charging API to support nesting 2020-10-18 09:27:09 -07:00
char_dev.c
compat_binfmt_elf.c
coredump.c coredump: fix core_pattern parse error 2020-12-06 10:19:07 -08:00
d_path.c fs: fix NULL dereference due to data race in prepend_path() 2020-10-14 14:54:45 -07:00
dax.c dax: fix ENOMEM handling in grab_mapping_entry() 2021-07-14 16:56:13 +02:00
dcache.c
dcookies.c
direct-io.c fs: direct-io: fix missing sdio->boundary 2021-04-14 08:41:58 +02:00
drop_caches.c
eventfd.c
eventpoll.c fs/epoll: restore waking from ep_done_scan() 2021-05-11 14:47:12 +02:00
exec.c Revert "Add a reference to ucounts for each cred" 2021-09-08 08:49:00 +02:00
fcntl.c fcntl: fix potential deadlock for &fasync_struct.fa_lock 2021-09-15 09:50:27 +02:00
fhandle.c
file_table.c task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
file.c kernel/io_uring: cancel io_uring before task works 2021-01-30 13:55:18 +01:00
filesystems.c
fs_context.c
fs_parser.c fs_parse: mark fs_param_bad_value() as static 2020-10-13 18:38:27 -07:00
fs_pin.c
fs_struct.c
fs_types.c
fs-writeback.c writeback: fix obtain a reference to a freeing memcg css 2021-07-14 16:56:31 +02:00
fsopen.c
init.c
inode.c fs: Handle I_DONTCACHE in iput_final() instead of generic_drop_inode() 2020-12-30 11:53:49 +01:00
internal.h cgroup1: fix leaked context root causing sporadic NULL deref in LTP 2021-07-31 08:16:11 +02:00
io_uring.c io_uring: fail links of cancelled timeouts 2021-09-18 13:40:05 +02:00
io-wq.c io-wq: fix wakeup race when adding new work 2021-09-18 13:40:06 +02:00
io-wq.h io_uring: always batch cancel in *cancel_files() 2021-02-13 13:54:56 +01:00
ioctl.c
Kconfig tmpfs: disallow CONFIG_TMPFS_INODE64 on alpha 2021-02-17 11:02:21 +01:00
Kconfig.binfmt
kernel_read_file.c fs/kernel_file_read: Add "offset" arg for partial reads 2020-10-05 13:37:04 +02:00
libfs.c libfs: fix error cast of negative value in simple_attr_write() 2020-11-22 10:48:22 -08:00
locks.c Revert "nfsd4: a client's own opens needn't prevent delegations" 2021-03-20 10:43:44 +01:00
Makefile Refactored code for 5.10: 2020-10-23 11:33:41 -07:00
mbcache.c
mount.h
mpage.c
namei.c LOOKUP_MOUNTPOINT: we are cleaning "jumped" flag too late 2021-04-14 08:41:58 +02:00
namespace.c fs: warn about impending deprecation of mandatory locks 2021-08-26 08:35:57 -04:00
no-block.c
nsfs.c
open.c open: don't silently ignore unknown O-flags in openat2() 2021-07-14 16:55:59 +02:00
pipe.c pipe: do FASYNC notifications for every pipe IO, not just state changes 2021-09-03 10:09:28 +02:00
pnode.c
pnode.h mount: fix mounting of detached mounts onto targets that reside on shared mounts 2021-03-17 17:06:13 +01:00
posix_acl.c
proc_namespace.c proc mountinfo: make splice available again 2020-12-30 11:54:02 +01:00
read_write.c Refactored code for 5.10: 2020-10-23 11:33:41 -07:00
readdir.c readdir: make sure to verify directory entry for legacy interfaces too 2021-04-21 13:00:54 +02:00
remap_range.c vfs: move the remap range helpers to remap_range.c 2020-10-15 09:48:49 -07:00
select.c kernel, fs: Introduce and use set_restart_fn() and arch_set_restart_data() 2021-03-25 09:04:16 +01:00
seq_file.c seq_file: disallow extremely large seq buffer allocations 2021-07-20 16:05:59 +02:00
signalfd.c
splice.c io_uring-5.10-2020-10-24 2020-10-24 12:40:18 -07:00
stack.c
stat.c fs: fix reporting supported extra file attributes for statx() 2021-05-11 14:47:33 +02:00
statfs.c
super.c vfs: move __sb_{start,end}_write* to fs.h 2020-11-10 16:53:11 -08:00
sync.c
timerfd.c
userfaultfd.c userfaultfd: prevent concurrent API initialization 2021-09-18 13:40:17 +02:00
utimes.c
xattr.c fs/xattr.c: fix kernel-doc warnings for setxattr & removexattr 2020-10-13 18:38:27 -07:00