Roman Penyaev 65759097d8 epoll: call final ep_events_available() check under the lock ... There is a possible race when ep_scan_ready_list() leaves ->rdllist and ->obflist empty for a short period of time although some events are pending. It is quite likely that ep_events_available() observes empty lists and goes to sleep. Since commit 339ddb53d3 ("fs/epoll: remove unnecessary wakeups of nested epoll") we are conservative in wakeups (there is only one place for wakeup and this is ep_poll_callback()), thus ep_events_available() must always observe correct state of two lists. The easiest and correct way is to do the final check under the lock. This does not impact the performance, since lock is taken anyway for adding a wait entry to the wait queue. The discussion of the problem can be found here: https://lore.kernel.org/linux-fsdevel/a2f22c3c-c25a-4bda-8339-a7bdaf17849e@akamai.com/ In this patch barrierless __set_current_state() is used. This is safe since waitqueue_active() is called under the same lock on wakeup side. Short-circuit for fatal signals (i.e. fatal_signal_pending() check) is moved to the line just before actual events harvesting routine. This is fully compliant to what is said in the comment of the patch where the actual fatal_signal_pending() check was added: c257a340ed ("fs, epoll: short circuit fetching events if thread has been killed"). Fixes: 339ddb53d3 ("fs/epoll: remove unnecessary wakeups of nested epoll") Reported-by: Jason Baron <jbaron@akamai.com> Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Roman Penyaev <rpenyaev@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jason Baron <jbaron@akamai.com> Cc: Khazhismel Kumykov <khazhy@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200505145609.1865152-1-rpenyaev@suse.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2020-05-14 10:00:35 -07:00
..
9p	9p: read only once on O_NONBLOCK	2020-03-27 09:29:56 +00:00
adfs	fs/adfs: bigdir: Fix an error code in adfs_fplus_read()	2020-01-25 11:31:59 -05:00
affs	affs: fix a memory leak in affs_remount	2019-11-18 14:26:43 +01:00
afs	afs: Make record checking use TASK_UNINTERRUPTIBLE when appropriate	2020-04-24 16:33:32 +01:00
autofs	LOOKUP_MOUNTPOINT: fold path_mountpointat() into path_lookupat()	2020-03-13 21:08:17 -04:00
befs	fs: Fill in max and min timestamps in superblock	2019-08-30 07:27:17 -07:00
bfs	fs: Fill in max and min timestamps in superblock	2019-08-30 07:27:17 -07:00
btrfs	btrfs: fix gcc-4.8 build warning for struct initializer	2020-04-30 12:17:49 +02:00
cachefiles	cachefiles: drop direct usage of ->bmap method.	2020-02-03 08:05:56 -05:00
ceph	block-5.7-2020-05-09	2020-05-10 11:16:07 -07:00
cifs	cifs: fix uninitialised lease_key in open_shroot()	2020-04-22 20:29:11 -05:00
coda	y2038: add inode timestamp clamping	2019-09-19 09:42:37 -07:00
configfs	configfs: fix config_item refcnt leak in configfs_rmdir()	2020-04-27 08:17:10 +02:00
cramfs	cramfs: switch to use of errofc() et.al.	2020-02-07 14:48:41 -05:00
crypto	fscrypt updates for 5.7	2020-03-31 12:58:36 -07:00
debugfs	debugfs: remove return value of debugfs_create_u32()	2020-04-17 17:08:50 +02:00
devpts	devpts_pty_kill(): don't bother with d_delete()	2019-09-03 09:30:56 -04:00
dlm	dlm: use SO_SNDTIMEO_NEW instead of SO_SNDTIMEO_OLD	2019-12-18 18:07:31 +01:00
ecryptfs	eCryptfs fixes for 5.6-rc3	2020-02-17 21:08:37 -08:00
efivarfs	efi: Use more granular check for availability for variable services	2020-02-23 21:59:42 +01:00
efs	fs: Fill in max and min timestamps in superblock	2019-08-30 07:27:17 -07:00
erofs	erofs: handle corrupted images whose decompressed size less than it'd be	2020-03-03 23:40:52 +08:00
exfat	exfat: truncate atimes to 2s granularity	2020-04-22 20:14:06 +09:00
exportfs	race in exportfs_decode_fh()	2019-11-11 09:21:59 -05:00
ext2	ext2: fix empty body warnings when -Wextra is used	2020-03-23 13:01:37 +01:00
ext4	ext4: convert BUG_ON's to WARN_ON's in mballoc.c	2020-04-15 23:58:49 -04:00
f2fs	f2fs-for-5.7-rc1	2020-04-07 13:48:26 -07:00
fat	fat: fix uninit-memory access for partial initialized inode	2020-03-06 07:06:09 -06:00
freevxfs	fs: Fill in max and min timestamps in superblock	2019-08-30 07:27:17 -07:00
fscache	proc: convert everything to "struct proc_ops"	2020-02-04 03:05:26 +00:00
fuse	fuse: fix stack use after return	2020-02-13 09:16:07 +01:00
gfs2	Revert "gfs2: Don't demote a glock until its revokes are written"	2020-05-08 15:01:25 -05:00
hfs	hfs/hfsplus: use 64-bit inode timestamps	2019-12-18 18:07:32 +01:00
hfsplus	hfsplus: fix crash and filesystem corruption when deleting files	2020-04-10 15:36:20 -07:00
hostfs	hostfs: Use kasprintf() instead of fixed buffer formatting	2020-03-29 23:23:00 +02:00
hpfs	fs: compat_ioctl: move FITRIM emulation into file systems	2019-10-23 17:23:46 +02:00
hugetlbfs	hugetlbfs: Use i_mmap_rwsem to address page fault/truncate race	2020-04-02 09:35:32 -07:00
iomap	fibmap: Warn and return an error in case of block > INT_MAX	2020-04-30 07:57:46 -07:00
isofs	y2038: add inode timestamp clamping	2019-09-19 09:42:37 -07:00
jbd2	jbd2: improve comments about freeing data buffers whose page mapping is NULL	2020-03-05 20:25:05 -05:00
jffs2	fs_parse: fold fs_parameter_desc/fs_parameter_spec	2020-02-07 14:48:37 -05:00
jfs	Trivial cleanup for jfs	2020-02-05 05:28:20 +00:00
kernfs	kernfs: Add option to enable user xattrs	2020-03-16 15:53:47 -04:00
lockd	proc: convert everything to "struct proc_ops"	2020-02-04 03:05:26 +00:00
minix	fs: Fill in max and min timestamps in superblock	2019-08-30 07:27:17 -07:00
nfs	NFS: Fix a race in __nfs_list_for_each_server()	2020-04-30 15:08:26 -04:00
nfs_common	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
nfsd	SUNRPC: Fix backchannel RPC soft lockups	2020-04-17 12:40:31 -04:00
nilfs2	fs: compat_ioctl: move FITRIM emulation into file systems	2019-10-23 17:23:46 +02:00
nls	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
notify	fanotify: Fix the checks in fanotify_fsid_equal	2020-03-30 12:40:53 +02:00
ntfs	fs/buffer: Make BH_Uptodate_Lock bit_spin_lock a regular spinlock_t	2020-03-28 13:21:08 +01:00
ocfs2	dlmfs_file_write(): fix the bogosity in handling non-zero *ppos	2020-04-23 13:45:27 -04:00
omfs	fs: omfs: Initialize filesystem timestamp ranges	2019-08-30 08:11:25 -07:00
openpromfs	Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2019-07-19 10:42:02 -07:00
orangefs	orangefs: don't mess with I_DIRTY_TIMES in orangefs_flush	2020-04-08 09:39:11 -04:00
overlayfs	ovl: enable xino automatically in more cases	2020-03-27 16:51:02 +01:00
proc	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2020-04-25 12:25:32 -07:00
pstore	pstore/ram: Replace zero-length array with flexible-array member	2020-03-09 14:45:40 -07:00
qnx4	fs: Fill in max and min timestamps in superblock	2019-08-30 07:27:17 -07:00
qnx6	fs: Fill in max and min timestamps in superblock	2019-08-30 07:27:17 -07:00
quota	\n	2020-01-30 15:37:41 -08:00
ramfs	fs_parse: fold fs_parameter_desc/fs_parameter_spec	2020-02-07 14:48:37 -05:00
reiserfs	reiserfs: clean up several indentation issues	2020-04-07 10:43:44 -07:00
romfs	Merge branch 'work.mount2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2019-09-19 10:06:57 -07:00
squashfs	Merge branch 'work.mount2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2019-09-19 10:06:57 -07:00
sysfs	sysfs: remove redundant __compat_only_sysfs_link_entry_to_kobj fn	2020-04-05 11:34:35 -07:00
sysv	fs: sysv: Initialize filesystem timestamp ranges	2019-08-30 07:27:18 -07:00
tracefs	simple_recursive_removal(): kernel-side rm -rf for ramfs-style filesystems	2019-12-10 22:29:58 -05:00
ubifs	This pull request contains fixes for UBI and UBIFS:	2020-04-07 12:40:56 -07:00
udf	change email address for Pali Rohár	2020-04-10 15:36:22 -07:00
ufs	y2038: add inode timestamp clamping	2019-09-19 09:42:37 -07:00
unicode	.gitignore: add SPDX License Identifier	2020-03-25 11:50:48 +01:00
vboxsf	vboxsf: don't use the source name in the bdi name	2020-05-07 08:45:47 -06:00
verity	fs-verity: use u64_to_user_ptr()	2020-01-14 13:28:28 -08:00
xfs	xfs: move inode flush to the sync workqueue	2020-04-16 09:07:42 -07:00
zonefs	zonfs: Fix handling of read-only zones	2020-03-25 11:28:26 +09:00
Kconfig	exfat: add Kconfig and Makefile	2020-03-05 21:00:40 -05:00
Kconfig.binfmt	binfmt_flat: make support for old format binaries optional	2019-06-24 09:16:47 +10:00
Makefile	exfat: add Kconfig and Makefile	2020-03-05 21:00:40 -05:00
aio.c	aio: prevent potential eventfd recursion on poll	2020-02-03 17:27:47 -07:00
anon_inodes.c	Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2019-07-19 10:42:02 -07:00
attr.c	utimes: Clamp the timestamps in notify_change()	2019-12-08 19:10:50 -05:00
bad_inode.c	…
binfmt_aout.c	treewide: Add SPDX license identifier for more missed files	2019-05-21 10:50:45 +02:00
binfmt_elf.c	fs/binfmt_elf.c: don't free interpreter's ELF pheaders on common path	2020-04-07 10:43:44 -07:00
binfmt_elf_fdpic.c	y2038: elfcore: Use __kernel_old_timeval for process times	2019-11-15 14:38:29 +01:00
binfmt_em86.c	treewide: Add SPDX license identifier for more missed files	2019-05-21 10:50:45 +02:00
binfmt_flat.c	fs/binfmt_flat.c: remove set but not used variable 'inode'	2019-07-16 19:23:22 -07:00
binfmt_misc.c	Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2019-07-19 10:42:02 -07:00
binfmt_script.c	treewide: Add SPDX license identifier for more missed files	2019-05-21 10:50:45 +02:00
block_dev.c	block: remove unused header	2020-04-21 09:51:10 -06:00
buffer.c	block-5.7-2020-04-24	2020-04-24 12:44:19 -07:00
char_dev.c	chardev: Avoid potential use-after-free in 'chrdev_open()'	2020-01-06 20:10:26 +01:00
compat.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
compat_binfmt_elf.c	y2038: elfcore: Use __kernel_old_timeval for process times	2019-11-15 14:38:29 +01:00
coredump.c	coredump: fix crash when umh is disabled	2020-04-28 17:54:13 +02:00
d_path.c	[PATCH] fix d_absolute_path() interplay with fsmount()	2019-08-30 19:31:09 -04:00
dax.c	dax,iomap: Add helper dax_iomap_zero() to zero a range	2020-04-02 19:15:03 -07:00
dcache.c	Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2019-12-08 11:08:28 -08:00
dcookies.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
direct-io.c	fs/direct-io.c: include fs/internal.h for missing prototype	2020-01-04 13:55:09 -08:00
drop_caches.c	fs: avoid softlockups in s_inodes iterators	2019-12-18 00:03:01 -05:00
eventfd.c	eventfd: track eventfd_signal() recursion depth	2020-02-03 17:27:38 -07:00
eventpoll.c	epoll: call final ep_events_available() check under the lock	2020-05-14 10:00:35 -07:00
exec.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2020-04-02 11:22:17 -07:00
fcntl.c	fcntl: Distribute switch variables for initialization	2020-03-03 10:55:06 -05:00
fhandle.c	fs/handle.c - fix up kerneldoc	2019-08-07 21:51:47 -04:00
file.c	io_uring: make sure openat/openat2 honor rlimit nofile	2020-03-20 08:47:27 -06:00
file_table.c	vfs: Export flush_delayed_fput for use by knfsd.	2019-08-19 11:00:39 -04:00
filesystems.c	fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once()	2020-04-10 15:36:22 -07:00
fs-writeback.c	memcg: fix a crash in wb_workfn when a device disappears	2020-01-31 10:30:36 -08:00
fs_context.c	add prefix to fs_context->log	2020-02-07 14:48:35 -05:00
fs_parser.c	fs_parse: remove pr_notice() about each validation	2020-04-02 09:35:26 -07:00
fs_pin.c	switch the remnants of releasing the mountpoint away from fs_pin	2019-07-16 22:52:37 -04:00
fs_struct.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
fs_types.c	…
fsopen.c	add prefix to fs_context->log	2020-02-07 14:48:35 -05:00
inode.c	futex: Fix inode life-time issue	2020-03-06 11:06:15 +01:00
internal.h	Merge branch 'work.dotdot1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2020-04-02 12:30:08 -07:00
io-wq.c	io_uring: use io-wq manager as backup task if task is exiting	2020-04-03 11:35:57 -06:00
io-wq.h	io_uring: use io-wq manager as backup task if task is exiting	2020-04-03 11:35:57 -06:00
io_uring.c	io_uring: don't use 'fd' for openat/openat2/statx	2020-05-07 14:56:15 -06:00
ioctl.c	fibmap: Warn and return an error in case of block > INT_MAX	2020-04-30 07:57:46 -07:00
libfs.c	libfs: fix infoleak in simple_attr_read()	2020-03-24 13:27:16 +01:00
locks.c	locks: reinstate locks_delete_block optimization	2020-03-18 13:03:38 -07:00
mbcache.c	treewide: Add SPDX license identifier for more missed files	2019-05-21 10:50:45 +02:00
mount.h	switch the remnants of releasing the mountpoint away from fs_pin	2019-07-16 22:52:37 -04:00
mpage.c	fs: move guard_bio_eod() after bio_set_op_attrs	2020-01-09 08:16:12 -07:00
namei.c	fix a braino in legitimize_path()	2020-04-06 10:38:59 -04:00
namespace.c	LOOKUP_MOUNTPOINT: fold path_mountpointat() into path_lookupat()	2020-03-13 21:08:17 -04:00
no-block.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
nsfs.c	fs/nsfs.c: Added ns_match	2020-03-12 17:33:11 -07:00
open.c	Merge branch 'work.dotdot1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2020-04-02 12:30:08 -07:00
pipe.c	mm: kmem: rename memcg_kmem_(un)charge() into memcg_kmem_(un)charge_page()	2020-04-02 09:35:28 -07:00
pnode.c	propagate_one(): mnt_set_mountpoint() needs mount_lock	2020-04-27 10:37:14 -04:00
pnode.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 209	2019-05-30 11:29:53 -07:00
posix_acl.c	fs/posix_acl.c: fix kernel-doc warnings	2020-01-04 13:55:09 -08:00
proc_namespace.c	vfs: subtype handling moved to fuse	2019-09-06 21:28:49 +02:00
read_write.c	powerpc: Add back __ARCH_WANT_SYS_LLSEEK macro	2020-04-03 00:09:59 +11:00
readdir.c	readdir: make user_access_begin() use the real access range	2020-01-23 10:15:28 -08:00
select.c	y2038: syscalls: change remaining timeval to __kernel_old_timeval	2019-11-15 14:38:29 +01:00
seq_file.c	fs/seq_file.c: seq_read(): add info message about buggy .next functions	2020-04-10 15:36:22 -07:00
signalfd.c	…
splice.c	splice: move f_mode checks to do_{splice,tee}()	2020-05-07 09:45:07 -06:00
stack.c	sched/rt, fs: Use CONFIG_PREEMPTION	2019-12-08 14:37:36 +01:00
stat.c	fs: make two stat prep helpers available	2020-01-20 17:03:54 -07:00
statfs.c	vfs: Fix EOVERFLOW testing in put_compat_statfs64	2019-10-03 14:21:35 -07:00
super.c	Fix use after free in get_tree_bdev()	2020-04-28 14:37:40 -07:00
sync.c	fs/sync.c: sync_file_range(2) may use WB_SYNC_ALL writeback	2019-05-14 09:47:50 -07:00
timerfd.c	timerfd: Make timerfd_settime() time namespace aware	2020-01-14 12:20:53 +01:00
userfaultfd.c	userfaultfd: wp: declare _UFFDIO_WRITEPROTECT conditionally	2020-04-07 10:43:40 -07:00
utimes.c	utimes: Clamp the timestamps in notify_change()	2019-12-08 19:10:50 -05:00
xattr.c	kernfs: Add removed_size out param for simple_xattr_set	2020-03-16 15:53:47 -04:00