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ca10845a56
While running btrfs/061, btrfs/073, btrfs/078, or btrfs/178 we hit the
following lockdep splat:
======================================================
WARNING: possible circular locking dependency detected
5.9.0-rc3+ #4 Not tainted
------------------------------------------------------
kswapd0/100 is trying to acquire lock:
ffff96ecc22ef4a0 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x330
but task is already holding lock:
ffffffff8dd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (fs_reclaim){+.+.}-{0:0}:
fs_reclaim_acquire+0x65/0x80
slab_pre_alloc_hook.constprop.0+0x20/0x200
kmem_cache_alloc+0x37/0x270
alloc_inode+0x82/0xb0
iget_locked+0x10d/0x2c0
kernfs_get_inode+0x1b/0x130
kernfs_get_tree+0x136/0x240
sysfs_get_tree+0x16/0x40
vfs_get_tree+0x28/0xc0
path_mount+0x434/0xc00
__x64_sys_mount+0xe3/0x120
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #2 (kernfs_mutex){+.+.}-{3:3}:
__mutex_lock+0x7e/0x7e0
kernfs_add_one+0x23/0x150
kernfs_create_link+0x63/0xa0
sysfs_do_create_link_sd+0x5e/0xd0
btrfs_sysfs_add_devices_dir+0x81/0x130
btrfs_init_new_device+0x67f/0x1250
btrfs_ioctl+0x1ef/0x2e20
__x64_sys_ioctl+0x83/0xb0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}:
__mutex_lock+0x7e/0x7e0
btrfs_chunk_alloc+0x125/0x3a0
find_free_extent+0xdf6/0x1210
btrfs_reserve_extent+0xb3/0x1b0
btrfs_alloc_tree_block+0xb0/0x310
alloc_tree_block_no_bg_flush+0x4a/0x60
__btrfs_cow_block+0x11a/0x530
btrfs_cow_block+0x104/0x220
btrfs_search_slot+0x52e/0x9d0
btrfs_insert_empty_items+0x64/0xb0
btrfs_insert_delayed_items+0x90/0x4f0
btrfs_commit_inode_delayed_items+0x93/0x140
btrfs_log_inode+0x5de/0x2020
btrfs_log_inode_parent+0x429/0xc90
btrfs_log_new_name+0x95/0x9b
btrfs_rename2+0xbb9/0x1800
vfs_rename+0x64f/0x9f0
do_renameat2+0x320/0x4e0
__x64_sys_rename+0x1f/0x30
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #0 (&delayed_node->mutex){+.+.}-{3:3}:
__lock_acquire+0x119c/0x1fc0
lock_acquire+0xa7/0x3d0
__mutex_lock+0x7e/0x7e0
__btrfs_release_delayed_node.part.0+0x3f/0x330
btrfs_evict_inode+0x24c/0x500
evict+0xcf/0x1f0
dispose_list+0x48/0x70
prune_icache_sb+0x44/0x50
super_cache_scan+0x161/0x1e0
do_shrink_slab+0x178/0x3c0
shrink_slab+0x17c/0x290
shrink_node+0x2b2/0x6d0
balance_pgdat+0x30a/0x670
kswapd+0x213/0x4c0
kthread+0x138/0x160
ret_from_fork+0x1f/0x30
other info that might help us debug this:
Chain exists of:
&delayed_node->mutex --> kernfs_mutex --> fs_reclaim
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(kernfs_mutex);
lock(fs_reclaim);
lock(&delayed_node->mutex);
*** DEADLOCK ***
3 locks held by kswapd0/100:
#0: ffffffff8dd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30
#1: ffffffff8dd65c50 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x115/0x290
#2: ffff96ed2ade30e0 (&type->s_umount_key#36){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0
stack backtrace:
CPU: 0 PID: 100 Comm: kswapd0 Not tainted 5.9.0-rc3+ #4
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Call Trace:
dump_stack+0x8b/0xb8
check_noncircular+0x12d/0x150
__lock_acquire+0x119c/0x1fc0
lock_acquire+0xa7/0x3d0
? __btrfs_release_delayed_node.part.0+0x3f/0x330
__mutex_lock+0x7e/0x7e0
? __btrfs_release_delayed_node.part.0+0x3f/0x330
? __btrfs_release_delayed_node.part.0+0x3f/0x330
? lock_acquire+0xa7/0x3d0
? find_held_lock+0x2b/0x80
__btrfs_release_delayed_node.part.0+0x3f/0x330
btrfs_evict_inode+0x24c/0x500
evict+0xcf/0x1f0
dispose_list+0x48/0x70
prune_icache_sb+0x44/0x50
super_cache_scan+0x161/0x1e0
do_shrink_slab+0x178/0x3c0
shrink_slab+0x17c/0x290
shrink_node+0x2b2/0x6d0
balance_pgdat+0x30a/0x670
kswapd+0x213/0x4c0
? _raw_spin_unlock_irqrestore+0x41/0x50
? add_wait_queue_exclusive+0x70/0x70
? balance_pgdat+0x670/0x670
kthread+0x138/0x160
? kthread_create_worker_on_cpu+0x40/0x40
ret_from_fork+0x1f/0x30
This happens because we are holding the chunk_mutex at the time of
adding in a new device. However we only need to hold the
device_list_mutex, as we're going to iterate over the fs_devices
devices. Move the sysfs init stuff outside of the chunk_mutex to get
rid of this lockdep splat.
CC: stable@vger.kernel.org # 4.4.x:
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.. | ||
9p | ||
adfs | ||
affs | ||
afs | ||
autofs | ||
befs | ||
bfs | ||
btrfs | ||
cachefiles | ||
ceph | ||
cifs | ||
coda | ||
configfs | ||
cramfs | ||
crypto | ||
debugfs | ||
devpts | ||
dlm | ||
ecryptfs | ||
efivarfs | ||
efs | ||
erofs | ||
exfat | ||
exportfs | ||
ext2 | ||
ext4 | ||
f2fs | ||
fat | ||
freevxfs | ||
fscache | ||
fuse | ||
gfs2 | ||
hfs | ||
hfsplus | ||
hostfs | ||
hpfs | ||
hugetlbfs | ||
iomap | ||
isofs | ||
jbd2 | ||
jffs2 | ||
jfs | ||
kernfs | ||
lockd | ||
minix | ||
nfs | ||
nfs_common | ||
nfsd | ||
nilfs2 | ||
nls | ||
notify | ||
ntfs | ||
ocfs2 | ||
omfs | ||
openpromfs | ||
orangefs | ||
overlayfs | ||
proc | ||
pstore | ||
qnx4 | ||
qnx6 | ||
quota | ||
ramfs | ||
reiserfs | ||
romfs | ||
squashfs | ||
sysfs | ||
sysv | ||
tracefs | ||
ubifs | ||
udf | ||
ufs | ||
unicode | ||
vboxsf | ||
verity | ||
xfs | ||
zonefs | ||
aio.c | ||
anon_inodes.c | ||
attr.c | ||
bad_inode.c | ||
binfmt_aout.c | ||
binfmt_elf.c | ||
binfmt_elf_fdpic.c | ||
binfmt_em86.c | ||
binfmt_flat.c | ||
binfmt_misc.c | ||
binfmt_script.c | ||
block_dev.c | ||
buffer.c | ||
char_dev.c | ||
compat.c | ||
compat_binfmt_elf.c | ||
coredump.c | ||
d_path.c | ||
dax.c | ||
dcache.c | ||
dcookies.c | ||
direct-io.c | ||
drop_caches.c | ||
eventfd.c | ||
eventpoll.c | ||
exec.c | ||
fcntl.c | ||
fhandle.c | ||
file.c | ||
file_table.c | ||
filesystems.c | ||
fs-writeback.c | ||
fs_context.c | ||
fs_parser.c | ||
fs_pin.c | ||
fs_struct.c | ||
fs_types.c | ||
fsopen.c | ||
init.c | ||
inode.c | ||
internal.h | ||
io-wq.c | ||
io-wq.h | ||
io_uring.c | ||
ioctl.c | ||
Kconfig | ||
Kconfig.binfmt | ||
libfs.c | ||
locks.c | ||
Makefile | ||
mbcache.c | ||
mount.h | ||
mpage.c | ||
namei.c | ||
namespace.c | ||
no-block.c | ||
nsfs.c | ||
open.c | ||
pipe.c | ||
pnode.c | ||
pnode.h | ||
posix_acl.c | ||
proc_namespace.c | ||
read_write.c | ||
readdir.c | ||
select.c | ||
seq_file.c | ||
signalfd.c | ||
splice.c | ||
stack.c | ||
stat.c | ||
statfs.c | ||
super.c | ||
sync.c | ||
timerfd.c | ||
userfaultfd.c | ||
utimes.c | ||
xattr.c |