kernel_optimize_test/fs
Eric W. Biederman ab7709b551 exec: Transform exec_update_mutex into a rw_semaphore
[ Upstream commit f7cfd871ae0c5008d94b6f66834e7845caa93c15 ]

Recently syzbot reported[0] that there is a deadlock amongst the users
of exec_update_mutex.  The problematic lock ordering found by lockdep
was:

   perf_event_open  (exec_update_mutex -> ovl_i_mutex)
   chown            (ovl_i_mutex       -> sb_writes)
   sendfile         (sb_writes         -> p->lock)
     by reading from a proc file and writing to overlayfs
   proc_pid_syscall (p->lock           -> exec_update_mutex)

While looking at possible solutions it occured to me that all of the
users and possible users involved only wanted to state of the given
process to remain the same.  They are all readers.  The only writer is
exec.

There is no reason for readers to block on each other.  So fix
this deadlock by transforming exec_update_mutex into a rw_semaphore
named exec_update_lock that only exec takes for writing.

Cc: Jann Horn <jannh@google.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christopher Yeoh <cyeoh@au1.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Fixes: eea9673250 ("exec: Add exec_update_mutex to replace cred_guard_mutex")
[0] https://lkml.kernel.org/r/00000000000063640c05ade8e3de@google.com
Reported-by: syzbot+db9cdf3dd1f64252c6ef@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/87ft4mbqen.fsf@x220.int.ebiederm.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-01-09 13:46:24 +01:00
..
9p fs: 9p: add generic splice_write file operation 2020-12-01 21:40:47 +01:00
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 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
afs afs: Fix memory leak when mounting with multiple source parameters 2020-12-08 15:59:25 -08:00
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: fix race when defragmenting leads to unnecessary IO 2020-12-30 11:54:13 +01:00
cachefiles cachefiles: Handle readpage error correctly 2020-10-26 10:42:54 -07:00
ceph ceph: fix inode refcount leak when ceph_fill_inode on non-I_NEW inode fails 2021-01-06 14:56:55 +01:00
cifs SMB3.1.1: do not log warning message if server doesn't populate salt 2020-12-30 11:54:17 +01:00
coda
configfs fs: configfs: delete repeated words in comments 2020-10-16 11:11:19 -07:00
cramfs
crypto fscrypt: add fscrypt_is_nokey_name() 2020-12-26 16:02:43 +01:00
debugfs debugfs: remove return value of debugfs_create_devm_seqfile() 2020-10-30 08:37:39 +01:00
devpts
dlm networking changes for the 5.10 merge window 2020-10-15 18:42:13 -07:00
ecryptfs
efivarfs efivarfs: revert "fix memory leak in efivarfs_create()" 2020-11-25 16:55:02 +01:00
efs
erofs erofs: avoid using generic_block_bmap 2020-12-30 11:53:46 +01:00
exfat exfat: Avoid allocating upcase table using kcalloc() 2020-12-26 16:02:38 +01:00
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: avoid s_mb_prefetch to be zero in individual scenarios 2021-01-06 14:56:56 +01:00
f2fs f2fs: fix race of pending_pages in decompression 2021-01-06 14:56:54 +01:00
fat
freevxfs
fscache
fuse fuse: fix bad inode 2021-01-09 13:46:24 +01:00
gfs2 gfs2: Fix deadlock between gfs2_{create_inode,inode_lookup} and delete_work_func 2020-12-01 00:21:10 +01:00
hfs fs: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
hfsplus fs: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
hostfs
hpfs
hugetlbfs
iomap iomap: clean up writeback state logic on writepage error 2020-11-04 08:52:46 -08:00
isofs fs: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
jbd2 jbd2: fix kernel-doc markups 2020-11-19 22:38:29 -05:00
jffs2 jffs2: Fix NULL pointer dereference in rp_size fs option parsing 2021-01-06 14:56:49 +01:00
jfs jfs: Fix array index bounds check in dbAdjTree 2020-12-30 11:54:18 +01:00
kernfs
lockd lockd: don't use interval-based rebinding over TCP 2020-12-30 11:53:30 +01:00
minix
nfs NFSv4.2: Don't error when exiting early on a READ_PLUS buffer overflow 2021-01-06 14:56:55 +01:00
nfs_common nfs_common: need lock during iterate through the list 2020-12-30 11:53:45 +01:00
nfsd fsnotify: generalize handle_inode_event() 2020-12-30 11:54:18 +01:00
nilfs2 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
nls
notify fsnotify: fix events reported to watching parent and child 2020-12-30 11:54:18 +01:00
ntfs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
ocfs2 ocfs2: initialize ip_next_orphan 2020-11-14 11:26:04 -08:00
omfs
openpromfs
orangefs
overlayfs ovl: make ioctl() safe 2020-12-30 11:54:16 +01:00
proc exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
pstore
qnx4
qnx6
quota quota: Don't overflow quota file offsets 2021-01-06 14:56:53 +01:00
ramfs ramfs: fix nommu mmap with gaps in the page cache 2020-10-16 11:11:22 -07:00
reiserfs reiserfs: add check for an invalid ih_entry_count 2021-01-06 14:56:52 +01:00
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 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
sysfs
sysv
tracefs
ubifs ubifs: wbuf: Don't leak kernel memory to flash 2020-12-30 11:54:17 +01:00
udf Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
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 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2020-10-15 15:11:56 -07:00
verity
xfs xfs: revert "xfs: fix rmap key and record comparison functions" 2020-11-19 15:17:50 -08:00
zonefs zonefs: fix page reference and BIO leak 2020-12-10 15:14:19 +09:00
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_script.c
block_dev.c
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 fuse update for 5.10 2020-10-19 14:28:30 -07:00
dcache.c
dcookies.c
direct-io.c \n 2020-10-15 15:03:10 -07:00
drop_caches.c
eventfd.c
eventpoll.c epoll: check for events when removing a timed out thread from the wait queue 2020-12-30 11:54:00 +01:00
exec.c exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
fcntl.c fcntl: Fix potential deadlock in send_sig{io, urg}() 2021-01-06 14:56:53 +01:00
fhandle.c
file_table.c task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
file.c
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 block-5.10-2020-10-12 2020-10-13 12:12:44 -07:00
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
io_uring.c io_uring: remove racy overflow list fast checks 2021-01-06 14:56:55 +01:00
io-wq.c io-wq: cancel request if it's asking for files and we don't have them 2020-11-04 10:22:56 -07:00
io-wq.h io_uring: fix io_wqe->work_list corruption 2020-12-30 11:54:03 +01:00
ioctl.c
Kconfig
Kconfig.binfmt
kernel_read_file.c
libfs.c libfs: fix error cast of negative value in simple_attr_write() 2020-11-22 10:48:22 -08:00
locks.c
Makefile Refactored code for 5.10: 2020-10-23 11:33:41 -07:00
mbcache.c
mount.h
mpage.c
namei.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
namespace.c fs/namespace.c: WARN if mnt_count has become negative 2021-01-06 14:56:54 +01:00
no-block.c
nsfs.c
open.c openat2: reject RESOLVE_BENEATH|RESOLVE_IN_ROOT 2020-12-30 11:54:24 +01:00
pipe.c
pnode.c
pnode.h fs/namespace.c: WARN if mnt_count has become negative 2021-01-06 14:56:54 +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
remap_range.c vfs: move the remap range helpers to remap_range.c 2020-10-15 09:48:49 -07:00
select.c fs: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
seq_file.c fix return values of seq_read_iter() 2020-11-15 22:12:53 -05:00
signalfd.c
splice.c io_uring-5.10-2020-10-24 2020-10-24 12:40:18 -07:00
stack.c
stat.c
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 mm: remove the now-unnecessary mmget_still_valid() hack 2020-10-16 11:11:22 -07:00
utimes.c
xattr.c fs/xattr.c: fix kernel-doc warnings for setxattr & removexattr 2020-10-13 18:38:27 -07:00