[syzbot] [ocfs2?] possible deadlock in ocfs2_remove_btree_range (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: dcb6fa37fd7b Linux 6.18-rc3
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=12859812580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b8b659f0cab27b22
dashboard link: https://syzkaller.appspot.com/bug?extid=d83fe3748c366683cd55
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ae6bec0d0398/disk-dcb6fa37.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dcc732da66c3/vmlinux-dcb6fa37.xz
kernel image: https://storage.googleapis.com/syzbot-assets/301d1bbdecc2/Image-dcb6fa37.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d83fe3...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.278/8010 is trying to acquire lock:
ffff0000d6dbc610 (sb_internal#3){.+.+}-{0:0}, at: ocfs2_remove_btree_range+0x67c/0x11cc fs/ocfs2/alloc.c:5760

but task is already holding lock:
ffff0000f676a640 (&ocfs2_sysfile_lock_key[TRUNCATE_LOG_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
ffff0000f676a640 (&ocfs2_sysfile_lock_key[TRUNCATE_LOG_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_remove_btree_range+0x524/0x11cc fs/ocfs2/alloc.c:5750

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&ocfs2_sysfile_lock_key[TRUNCATE_LOG_SYSTEM_INODE]){+.+.}-{4:4}:
down_write+0x50/0xc0 kernel/locking/rwsem.c:1590
inode_lock include/linux/fs.h:980 [inline]
ocfs2_xattr_set+0x8a8/0xe9c fs/ocfs2/xattr.c:3622
ocfs2_xattr_trusted_set+0x4c/0x64 fs/ocfs2/xattr.c:7336
__vfs_setxattr+0x3d8/0x400 fs/xattr.c:200
__vfs_setxattr_noperm+0x120/0x5c4 fs/xattr.c:234
__vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:295
vfs_setxattr+0x158/0x2ac fs/xattr.c:321
ovl_do_setxattr fs/overlayfs/overlayfs.h:317 [inline]
ovl_setxattr fs/overlayfs/overlayfs.h:329 [inline]
ovl_make_workdir fs/overlayfs/super.c:725 [inline]
ovl_get_workdir+0x9d4/0x1270 fs/overlayfs/super.c:837
ovl_fill_super+0x10d8/0x3118 fs/overlayfs/super.c:1468
vfs_get_super fs/super.c:1324 [inline]
get_tree_nodev+0xb4/0x144 fs/super.c:1343
ovl_get_tree+0x28/0x38 fs/overlayfs/params.c:708
vfs_get_tree+0x90/0x28c fs/super.c:1751
fc_mount fs/namespace.c:1208 [inline]
do_new_mount_fc fs/namespace.c:3651 [inline]
do_new_mount+0x284/0x944 fs/namespace.c:3727
path_mount+0x5b4/0xdfc fs/namespace.c:4037
do_mount fs/namespace.c:4050 [inline]
__do_sys_mount fs/namespace.c:4238 [inline]
__se_sys_mount fs/namespace.c:4215 [inline]
__arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4215
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:746
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:765
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

-> #3 (&oi->ip_xattr_sem){++++}-{4:4}:
down_write+0x50/0xc0 kernel/locking/rwsem.c:1590
ocfs2_xattr_set_handle+0x2a8/0x5e4 fs/ocfs2/xattr.c:3501
ocfs2_init_security_set+0xb4/0xd8 fs/ocfs2/xattr.c:7307
ocfs2_mknod+0x106c/0x1cf0 fs/ocfs2/namei.c:422
ocfs2_create+0x190/0x474 fs/ocfs2/namei.c:676
lookup_open fs/namei.c:3796 [inline]
open_last_lookups fs/namei.c:3895 [inline]
path_openat+0x12d8/0x2c40 fs/namei.c:4131
do_filp_open+0x18c/0x36c fs/namei.c:4161
do_sys_openat2+0x11c/0x1b4 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__arm64_sys_openat+0x120/0x158 fs/open.c:1463
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:746
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:765
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

-> #2 (jbd2_handle){++++}-{0:0}:
start_this_handle+0xe74/0x10dc fs/jbd2/transaction.c:444
jbd2__journal_start+0x288/0x51c fs/jbd2/transaction.c:501
jbd2_journal_start+0x3c/0x4c fs/jbd2/transaction.c:540
ocfs2_start_trans+0x368/0x6b0 fs/ocfs2/journal.c:374
ocfs2_block_group_alloc fs/ocfs2/suballoc.c:685 [inline]
ocfs2_reserve_suballoc_bits+0x630/0x3b9c fs/ocfs2/suballoc.c:834
ocfs2_reserve_new_metadata_blocks+0x368/0x810 fs/ocfs2/suballoc.c:984
ocfs2_mknod+0xbd8/0x1cf0 fs/ocfs2/namei.c:350
ocfs2_create+0x190/0x474 fs/ocfs2/namei.c:676
lookup_open fs/namei.c:3796 [inline]
open_last_lookups fs/namei.c:3895 [inline]
path_openat+0x12d8/0x2c40 fs/namei.c:4131
do_filp_open+0x18c/0x36c fs/namei.c:4161
do_sys_openat2+0x11c/0x1b4 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__arm64_sys_openat+0x120/0x158 fs/open.c:1463
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:746
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:765
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

-> #1 (&journal->j_trans_barrier){.+.+}-{4:4}:
down_read+0x58/0x2f8 kernel/locking/rwsem.c:1537
ocfs2_start_trans+0x35c/0x6b0 fs/ocfs2/journal.c:372
ocfs2_block_group_alloc fs/ocfs2/suballoc.c:685 [inline]
ocfs2_reserve_suballoc_bits+0x630/0x3b9c fs/ocfs2/suballoc.c:834
ocfs2_reserve_new_metadata_blocks+0x368/0x810 fs/ocfs2/suballoc.c:984
ocfs2_mknod+0xbd8/0x1cf0 fs/ocfs2/namei.c:350
ocfs2_create+0x190/0x474 fs/ocfs2/namei.c:676
lookup_open fs/namei.c:3796 [inline]
open_last_lookups fs/namei.c:3895 [inline]
path_openat+0x12d8/0x2c40 fs/namei.c:4131
do_filp_open+0x18c/0x36c fs/namei.c:4161
do_sys_openat2+0x11c/0x1b4 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__arm64_sys_openat+0x120/0x158 fs/open.c:1463
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:746
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:765
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

-> #0 (sb_internal#3){.+.+}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237
lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
__sb_start_write include/linux/fs.h:1916 [inline]
sb_start_intwrite include/linux/fs.h:2099 [inline]
ocfs2_start_trans+0x1f4/0x6b0 fs/ocfs2/journal.c:370
ocfs2_remove_btree_range+0x67c/0x11cc fs/ocfs2/alloc.c:5760
ocfs2_remove_inode_range+0xbc0/0x2174 fs/ocfs2/file.c:1907
ocfs2_reflink_remap_extent fs/ocfs2/refcounttree.c:4534 [inline]
ocfs2_reflink_remap_blocks+0x950/0x14b0 fs/ocfs2/refcounttree.c:4681
ocfs2_remap_file_range+0x3fc/0x638 fs/ocfs2/file.c:2740
vfs_copy_file_range+0xbc4/0x10f8 fs/read_write.c:1598
__do_sys_copy_file_range fs/read_write.c:1681 [inline]
__se_sys_copy_file_range fs/read_write.c:1648 [inline]
__arm64_sys_copy_file_range+0x308/0x5d4 fs/read_write.c:1648
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:746
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:765
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

other info that might help us debug this:

Chain exists of:
sb_internal#3 --> &oi->ip_xattr_sem --> &ocfs2_sysfile_lock_key[TRUNCATE_LOG_SYSTEM_INODE]

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ocfs2_sysfile_lock_key[TRUNCATE_LOG_SYSTEM_INODE]);
lock(&oi->ip_xattr_sem);
lock(&ocfs2_sysfile_lock_key[TRUNCATE_LOG_SYSTEM_INODE]);
rlock(sb_internal#3);

*** DEADLOCK ***

7 locks held by syz.0.278/8010:
#0: ffff0000d6dbc420 (sb_writers#15){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3111 [inline]
#0: ffff0000d6dbc420 (sb_writers#15){.+.+}-{0:0}, at: vfs_copy_file_range+0x868/0x10f8 fs/read_write.c:1586
#1: ffff0000f66289c0 (&sb->s_type->i_mutex_key#25){++++}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#1: ffff0000f66289c0 (&sb->s_type->i_mutex_key#25){++++}-{4:4}, at: lock_two_nondirectories+0xc4/0x150 fs/inode.c:1232
#2: ffff0000f81709c0 (&sb->s_type->i_mutex_key#25/4){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1025 [inline]
#2: ffff0000f81709c0 (&sb->s_type->i_mutex_key#25/4){+.+.}-{4:4}, at: lock_two_nondirectories+0xf0/0x150 fs/inode.c:1234
#3: ffff0000f8170660 (&ocfs2_file_ip_alloc_sem_key){++++}-{4:4}, at: ocfs2_remap_file_range+0x344/0x638 fs/ocfs2/file.c:2730
#4: ffff0000f6628660 (&ocfs2_file_ip_alloc_sem_key/1){+.+.}-{4:4}, at: ocfs2_remap_file_range+0x35c/0x638 fs/ocfs2/file.c:2732
#5: ffff0000d0555098 (&new->rf_sem){+.+.}-{4:4}, at: __ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:428 [inline]
#5: ffff0000d0555098 (&new->rf_sem){+.+.}-{4:4}, at: ocfs2_lock_refcount_tree+0x188/0x924 fs/ocfs2/refcounttree.c:463
#6: ffff0000f676a640 (&ocfs2_sysfile_lock_key[TRUNCATE_LOG_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#6: ffff0000f676a640 (&ocfs2_sysfile_lock_key[TRUNCATE_LOG_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_remove_btree_range+0x524/0x11cc fs/ocfs2/alloc.c:5750

stack backtrace:
CPU: 0 UID: 0 PID: 8010 Comm: syz.0.278 Not tainted syzkaller #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
__dump_stack+0x30/0x40 lib/dump_stack.c:94
dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
dump_stack+0x1c/0x28 lib/dump_stack.c:129
print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2043
check_noncircular+0x154/0x174 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237
lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
__sb_start_write include/linux/fs.h:1916 [inline]
sb_start_intwrite include/linux/fs.h:2099 [inline]
ocfs2_start_trans+0x1f4/0x6b0 fs/ocfs2/journal.c:370
ocfs2_remove_btree_range+0x67c/0x11cc fs/ocfs2/alloc.c:5760
ocfs2_remove_inode_range+0xbc0/0x2174 fs/ocfs2/file.c:1907
ocfs2_reflink_remap_extent fs/ocfs2/refcounttree.c:4534 [inline]
ocfs2_reflink_remap_blocks+0x950/0x14b0 fs/ocfs2/refcounttree.c:4681
ocfs2_remap_file_range+0x3fc/0x638 fs/ocfs2/file.c:2740
vfs_copy_file_range+0xbc4/0x10f8 fs/read_write.c:1598
__do_sys_copy_file_range fs/read_write.c:1681 [inline]
__se_sys_copy_file_range fs/read_write.c:1648 [inline]
__arm64_sys_copy_file_range+0x308/0x5d4 fs/read_write.c:1648
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:746
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:765
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596


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