Al Viro acfec9a5a8 livelock avoidance in sget() ... Eric Sandeen has found a nasty livelock in sget() - take a mount(2) about to fail. The superblock is on ->fs_supers, ->s_umount is held exclusive, ->s_active is 1. Along comes two more processes, trying to mount the same thing; sget() in each is picking that superblock, bumping ->s_count and trying to grab ->s_umount. ->s_active is 3 now. Original mount(2) finally gets to deactivate_locked_super() on failure; ->s_active is 2, superblock is still ->fs_supers because shutdown will *not* happen until ->s_active hits 0. ->s_umount is dropped and now we have two processes chasing each other: s_active = 2, A acquired ->s_umount, B blocked A sees that the damn thing is stillborn, does deactivate_locked_super() s_active = 1, A drops ->s_umount, B gets it A restarts the search and finds the same superblock. And bumps it ->s_active. s_active = 2, B holds ->s_umount, A blocked on trying to get it ... and we are in the earlier situation with A and B switched places. The root cause, of course, is that ->s_active should not grow until we'd got MS_BORN. Then failing ->mount() will have deactivate_locked_super() shut the damn thing down. Fortunately, it's easy to do - the key point is that grab_super() is called only for superblocks currently on ->fs_supers, so it can bump ->s_count and grab ->s_umount first, then check MS_BORN and bump ->s_active; we must never increment ->s_count for superblocks past ->kill_sb(), but grab_super() is never called for those. The bug is pretty old; we would've caught it by now, if not for accidental exclusion between sget() for block filesystems; the things like cgroup or e.g. mtd-based filesystems don't have anything of that sort, so they get bitten. The right way to deal with that is obviously to fix sget()... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>		2013-07-20 04:58:58 +04:00
..
9p	Second round of 9p patches for the 3.11 merge window.	2013-07-11 10:21:23 -07:00
adfs	Don't pass inode to ->d_hash() and ->d_compare()	2013-06-29 12:57:36 +04:00
affs	Don't pass inode to ->d_hash() and ->d_compare()	2013-06-29 12:57:36 +04:00
afs	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-07-03 09:10:19 -07:00
autofs4	helper for reading ->d_count	2013-07-05 18:59:33 +04:00
befs	[readdir] convert befs	2013-06-29 12:56:55 +04:00
bfs	[readdir] convert bfs	2013-06-29 12:56:33 +04:00
btrfs	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs	2013-07-09 12:33:09 -07:00
cachefiles	mm: remove lru parameter from __pagevec_lru_add and remove parts of pagevec API	2013-07-03 16:07:31 -07:00
ceph	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client	2013-07-09 12:39:10 -07:00
cifs	CIFS: Fix a deadlock when a file is reopened	2013-07-11 18:05:41 -05:00
coda	helper for reading ->d_count	2013-07-05 18:59:33 +04:00
configfs	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-07-14 11:42:26 -07:00
cramfs	[readdir] convert f2fs	2013-06-29 12:56:46 +04:00
debugfs	debugfs: write_file_bool() - ensure strtobool() operates on valid data	2013-06-03 13:55:02 -07:00
devpts
dlm	dlm: Avoid LVB truncation	2013-06-26 11:38:02 -05:00
ecryptfs	Code cleanups and improved buffer handling during page crypto operations	2013-07-11 10:20:18 -07:00
efivarfs	efivarfs: we can use simple_lookup() now	2013-07-14 17:48:35 +04:00
efs	[readdir] convert efs	2013-06-29 12:56:31 +04:00
exofs	Lots of bug fixes, cleanups and optimizations. In the bug fixes	2013-07-02 09:39:34 -07:00
exportfs	[readdir] constify ->actor	2013-06-29 12:57:05 +04:00
ext2	[O_TMPFILE] it's still short a few helpers, but infrastructure should be OK now...	2013-06-29 12:57:10 +04:00
ext3	Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs	2013-07-09 12:08:43 -07:00
ext4	Various regression and bug fixes for ext4.	2013-07-14 21:47:51 -07:00
f2fs	f2fs: fix readdir incorrectness	2013-07-08 13:35:48 +04:00
fat	fatfs: add FAT_IOCTL_GET_VOLUME_ID	2013-07-09 10:33:25 -07:00
freevxfs	[readdir] convert freevxfs	2013-06-29 12:56:53 +04:00
fscache	FS-Cache: Don't use spin_is_locked() in assertions	2013-06-19 14:16:47 +01:00
fuse	mm: use totalram_pages instead of num_physpages at runtime	2013-07-03 16:07:35 -07:00
gfs2	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-07-03 09:10:19 -07:00
hfs	Don't pass inode to ->d_hash() and ->d_compare()	2013-06-29 12:57:36 +04:00
hfsplus	Don't pass inode to ->d_hash() and ->d_compare()	2013-06-29 12:57:36 +04:00
hostfs	[readdir] convert hostfs	2013-06-29 12:56:59 +04:00
hpfs	Merge branch 'hpfs' from Mikulas Patocka	2013-07-04 11:22:55 -07:00
hppfs	clean up scary strncpy(dst, src, strlen(src)) uses	2013-07-03 16:07:41 -07:00
hugetlbfs	hugetlbfs: fix mmap failure in unaligned size request	2013-05-07 18:38:27 -07:00
isofs	Don't pass inode to ->d_hash() and ->d_compare()	2013-06-29 12:57:36 +04:00
jbd	jbd: change journal_invalidatepage() to accept length	2013-05-21 23:26:36 -04:00
jbd2	jbd2: invalidate handle if jbd2_journal_restart() fails	2013-07-01 08:12:41 -04:00
jffs2	[readdir] convert jffs2	2013-06-29 12:56:47 +04:00
jfs	A couple cleanups to JFS for 3.11	2013-07-11 10:19:34 -07:00
lockd	drivers: avoid parsing names as kthread_run() format strings	2013-07-03 16:07:41 -07:00
logfs	Lots of bug fixes, cleanups and optimizations. In the bug fixes	2013-07-02 09:39:34 -07:00
minix	minix: bug widening a binary "not" operation	2013-06-29 12:57:35 +04:00
ncpfs	ncpfs: fix error return code in ncp_parse_options()	2013-07-09 10:33:25 -07:00
nfs	NFS: Allow nfs_updatepage to extend a write under additional circumstances	2013-07-09 19:32:50 -04:00
nfs_common
nfsd	Merge branch 'for-3.11' of git://linux-nfs.org/~bfields/linux	2013-07-11 10:17:13 -07:00
nilfs2	helper for reading ->d_count	2013-07-05 18:59:33 +04:00
nls
notify	fsnotify: update comments concerning locking scheme	2013-07-09 10:33:20 -07:00
ntfs	Lots of bug fixes, cleanups and optimizations. In the bug fixes	2013-07-02 09:39:34 -07:00
ocfs2	ocfs2: fix NULL pointer dereference when traversing o2hb_all_regions	2013-07-03 16:07:25 -07:00
omfs	[readdir] convert omfs	2013-06-29 12:56:37 +04:00
openpromfs	[readdir] convert openpromfs	2013-06-29 12:56:32 +04:00
proc	fs/proc/kcore.c: using strlcpy() instead of strncpy()	2013-07-03 16:08:02 -07:00
pstore	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc	2013-07-04 10:29:23 -07:00
qnx4	[readdir] convert qnx4	2013-06-29 12:56:38 +04:00
qnx6	[readdir] convert qnx6	2013-06-29 12:56:39 +04:00
quota	quota: Convert use of typedef ctl_table to struct ctl_table	2013-07-04 19:22:55 +02:00
ramfs
reiserfs	Lots of bug fixes, cleanups and optimizations. In the bug fixes	2013-07-02 09:39:34 -07:00
romfs	[readdir] convert romfs	2013-06-29 12:56:29 +04:00
squashfs	[readdir] convert squashfs	2013-06-29 12:56:28 +04:00
sysfs	Driver core patches for 3.11-rc1	2013-07-02 11:44:19 -07:00
sysv	Don't pass inode to ->d_hash() and ->d_compare()	2013-06-29 12:57:36 +04:00
ubifs	Only a single patch which fixes a message.	2013-07-05 12:08:47 -07:00
udf	udf: provide ->tmpfile()	2013-06-29 12:57:12 +04:00
ufs	[readdir] simple local unixlike: switch to ->iterate()	2013-06-29 12:46:47 +04:00
xfs	xfs: update (#2) for 3.11-rc1	2013-07-13 11:40:24 -07:00
aio.c	aio: fix wrong comment in aio_complete()	2013-07-03 16:08:06 -07:00
anon_inodes.c
attr.c
bad_inode.c	[readdir] ->readdir() is gone	2013-06-29 12:57:04 +04:00
binfmt_aout.c	mm: remove free_area_cache	2013-07-10 18:11:34 -07:00
binfmt_elf_fdpic.c	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc	2013-05-02 10:16:16 -07:00
binfmt_elf.c	mm: remove free_area_cache	2013-07-10 18:11:34 -07:00
binfmt_em86.c
binfmt_flat.c	new helper: read_code()	2013-04-29 15:40:23 -04:00
binfmt_misc.c	binfmt_misc: reuse string_unescape_inplace()	2013-04-30 17:04:03 -07:00
binfmt_script.c
binfmt_som.c
bio-integrity.c
bio.c	Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block	2013-05-08 10:13:35 -07:00
block_dev.c	Merge branch 'for-3.11/core' of git://git.kernel.dk/linux-block	2013-07-11 13:03:24 -07:00
buffer.c	mm: vmscan: take page buffers dirty and locked state into account	2013-07-03 16:07:29 -07:00
char_dev.c
compat_binfmt_elf.c
compat_ioctl.c	compat.c: LOOP_CLR_FD is taken care of in loop.c itself...	2013-06-29 12:46:44 +04:00
compat.c	[readdir] constify ->actor	2013-06-29 12:57:05 +04:00
coredump.c	coredump: '% at the end' shouldn't bypass core_uses_pid logic	2013-07-03 16:08:02 -07:00
coredump.h
dcache.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-07-03 09:10:19 -07:00
dcookies.c
direct-io.c	Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block	2013-05-08 10:13:35 -07:00
drop_caches.c
eventfd.c
eventpoll.c	Merge branch 'akpm' (updates from Andrew Morton)	2013-07-03 17:12:13 -07:00
exec.c	fs/exec.c:de_thread: mt-exec should update ->real_start_time	2013-07-03 16:08:03 -07:00
fcntl.c
fhandle.c
file_table.c	fput: turn "list_head delayed_fput_list" into llist_head	2013-07-13 13:29:10 +04:00
file.c	don't bother with deferred freeing of fdtables	2013-05-01 17:31:42 -04:00
filesystems.c
fs_struct.c
fs-writeback.c	mm/writeback: don't check force_wait to handle bdi->work_list	2013-07-09 10:33:22 -07:00
generic_acl.c
inode.c	allow the temp files created by open() to be linked to	2013-06-29 12:57:11 +04:00
internal.h	constify rw_verify_area()	2013-06-29 12:57:34 +04:00
ioctl.c
ioprio.c
Kconfig	efivarfs: Move to fs/efivarfs	2013-04-17 13:25:09 +01:00
Kconfig.binfmt	fs: make binfmt support for #! scripts modular and removable	2013-04-30 17:04:04 -07:00
libfs.c	make simple_lookup() usable for filesystems that set ->s_d_op	2013-07-14 17:43:25 +04:00
locks.c	locks: move file_lock_list to a set of percpu hlist_heads and convert file_lock_lock to an lglock	2013-07-08 13:36:42 +04:00
Makefile	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-05-01 17:51:54 -07:00
mbcache.c
mount.h	get rid of full-hash scan on detaching vfsmounts	2013-04-09 14:12:52 -04:00
mpage.c
namei.c	Safer ABI for O_TMPFILE	2013-07-13 13:26:37 +04:00
namespace.c	create_mnt_ns: unidiomatic use of list_add()	2013-05-04 15:18:53 -04:00
no-block.c
open.c	allow O_TMPFILE to work with O_WRONLY	2013-07-20 03:11:32 +04:00
pipe.c	aio: don't include aio.h in sched.h	2013-05-07 20:16:25 -07:00
pnode.c	vfs: Fix invalid ida_remove() call	2013-05-31 15:16:33 -04:00
pnode.h	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-05-01 17:51:54 -07:00
posix_acl.c
proc_namespace.c
read_write.c	vfs: export lseek_execute() to modules	2013-07-03 16:23:27 +04:00
readdir.c	[readdir] constify ->actor	2013-06-29 12:57:05 +04:00
select.c	net: rename include/net/ll_poll.h to include/net/busy_poll.h	2013-07-10 17:08:27 -07:00
seq_file.c	seq_file: add seq_list_*_percpu helpers	2013-07-08 13:36:41 +04:00
signalfd.c
splice.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-07-03 09:10:19 -07:00
stack.c
stat.c
statfs.c
super.c	livelock avoidance in sget()	2013-07-20 04:58:58 +04:00
sync.c
timerfd.c	timerfd: Add alarm timers	2013-05-29 12:57:34 -07:00
utimes.c
xattr_acl.c
xattr.c