[v6.1] possible deadlock in ocfs2_lock_refcount_tree

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d7039b844a1c Linux 6.1.116
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1513535f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=e70423a11a31a773
dashboard link: https://syzkaller.appspot.com/bug?extid=640885a40c07e1675348
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3797d90cbed7/disk-d7039b84.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9726bc0bc28f/vmlinux-d7039b84.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0b4bbd21cac0/Image-d7039b84.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+640885...@syzkaller.appspotmail.com

loop2: detected capacity change from 0 to 32768
ocfs2: Mounting device (7,2) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
6.1.116-syzkaller #0 Not tainted
------------------------------------------------------
syz.2.455/6521 is trying to acquire lock:
ffff0000c9db4098 (&new->rf_sem){+.+.}-{3:3}, at: __ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:428 [inline]
ffff0000c9db4098 (&new->rf_sem){+.+.}-{3:3}, at: ocfs2_lock_refcount_tree+0x1f4/0xa48 fs/ocfs2/refcounttree.c:463

but task is already holding lock:
ffff0000f1d7b120 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_inode_lock_for_extent_tree+0x8c/0x26c fs/ocfs2/file.c:2205

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}:
down_read+0x64/0x308 kernel/locking/rwsem.c:1520
ocfs2_read_virt_blocks+0x2bc/0x9f8 fs/ocfs2/extent_map.c:976
ocfs2_read_dir_block fs/ocfs2/dir.c:508 [inline]
ocfs2_find_entry_el fs/ocfs2/dir.c:715 [inline]
ocfs2_find_entry+0x3ac/0x2620 fs/ocfs2/dir.c:1080
ocfs2_find_files_on_disk+0x130/0x468 fs/ocfs2/dir.c:1982
ocfs2_lookup_ino_from_name+0xb8/0x1d4 fs/ocfs2/dir.c:2004
_ocfs2_get_system_file_inode fs/ocfs2/sysfile.c:136 [inline]
ocfs2_get_system_file_inode+0x2c8/0x6b8 fs/ocfs2/sysfile.c:112
ocfs2_init_global_system_inodes+0x2bc/0x618 fs/ocfs2/super.c:457
ocfs2_initialize_super fs/ocfs2/super.c:2250 [inline]
ocfs2_fill_super+0x278c/0x4a0c fs/ocfs2/super.c:994
mount_bdev+0x274/0x370 fs/super.c:1443
ocfs2_mount+0x44/0x58 fs/ocfs2/super.c:1186
legacy_get_tree+0xd4/0x16c fs/fs_context.c:632
vfs_get_tree+0x90/0x274 fs/super.c:1573
do_new_mount+0x278/0x8fc fs/namespace.c:3056
path_mount+0x590/0xe5c fs/namespace.c:3386
do_mount fs/namespace.c:3399 [inline]
__do_sys_mount fs/namespace.c:3607 [inline]
__se_sys_mount fs/namespace.c:3584 [inline]
__arm64_sys_mount+0x45c/0x594 fs/namespace.c:3584
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #1 (&osb->system_file_mutex){+.+.}-{3:3}:
__mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
ocfs2_get_system_file_inode+0x180/0x6b8 fs/ocfs2/sysfile.c:101
ocfs2_reserve_suballoc_bits+0x14c/0x4428 fs/ocfs2/suballoc.c:776
ocfs2_reserve_new_metadata_blocks+0x384/0x848 fs/ocfs2/suballoc.c:978
ocfs2_add_refcount_flag+0x424/0x1180 fs/ocfs2/refcounttree.c:3683
ocfs2_reflink_remap_extent fs/ocfs2/refcounttree.c:4563 [inline]
ocfs2_reflink_remap_blocks+0xb7c/0x19e0 fs/ocfs2/refcounttree.c:4690
ocfs2_remap_file_range+0x504/0x794 fs/ocfs2/file.c:2696
vfs_copy_file_range+0xb84/0x122c fs/read_write.c:1518
__do_sys_copy_file_range fs/read_write.c:1596 [inline]
__se_sys_copy_file_range fs/read_write.c:1559 [inline]
__arm64_sys_copy_file_range+0x578/0x914 fs/read_write.c:1559
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #0 (&new->rf_sem){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
down_write+0x5c/0x88 kernel/locking/rwsem.c:1573
__ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:428 [inline]
ocfs2_lock_refcount_tree+0x1f4/0xa48 fs/ocfs2/refcounttree.c:463
ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3415 [inline]
ocfs2_refcount_cow+0x5f0/0xfa8 fs/ocfs2/refcounttree.c:3476
ocfs2_prepare_inode_for_write fs/ocfs2/file.c:2337 [inline]
ocfs2_file_write_iter+0xd6c/0x1fbc fs/ocfs2/file.c:2446
call_write_iter include/linux/fs.h:2265 [inline]
aio_write+0x588/0x824 fs/aio.c:1615
io_submit_one+0x824/0x15b8 fs/aio.c:2034
__do_sys_io_submit fs/aio.c:2093 [inline]
__se_sys_io_submit fs/aio.c:2063 [inline]
__arm64_sys_io_submit+0x248/0x3c8 fs/aio.c:2063
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

other info that might help us debug this:

Chain exists of:
&new->rf_sem --> &osb->system_file_mutex --> &ocfs2_file_ip_alloc_sem_key

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ocfs2_file_ip_alloc_sem_key);
lock(&osb->system_file_mutex);
lock(&ocfs2_file_ip_alloc_sem_key);
lock(&new->rf_sem);

*** DEADLOCK ***

2 locks held by syz.2.455/6521:
#0: ffff0000f1d7b488 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
#0: ffff0000f1d7b488 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: ocfs2_file_write_iter+0x3b4/0x1fbc fs/ocfs2/file.c:2396
#1: ffff0000f1d7b120 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_inode_lock_for_extent_tree+0x8c/0x26c fs/ocfs2/file.c:2205

stack backtrace:
CPU: 0 PID: 6521 Comm: syz.2.455 Not tainted 6.1.116-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call trace:
dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x58 lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2048
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2170
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x3338/0x7680 kernel/locking/lockdep.c:5049
lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662
down_write+0x5c/0x88 kernel/locking/rwsem.c:1573
__ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:428 [inline]
ocfs2_lock_refcount_tree+0x1f4/0xa48 fs/ocfs2/refcounttree.c:463
ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3415 [inline]
ocfs2_refcount_cow+0x5f0/0xfa8 fs/ocfs2/refcounttree.c:3476
ocfs2_prepare_inode_for_write fs/ocfs2/file.c:2337 [inline]
ocfs2_file_write_iter+0xd6c/0x1fbc fs/ocfs2/file.c:2446
call_write_iter include/linux/fs.h:2265 [inline]
aio_write+0x588/0x824 fs/aio.c:1615
io_submit_one+0x824/0x15b8 fs/aio.c:2034
__do_sys_io_submit fs/aio.c:2093 [inline]
__se_sys_io_submit fs/aio.c:2063 [inline]
__arm64_sys_io_submit+0x248/0x3c8 fs/aio.c:2063
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585


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