syzbot

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.151/5005 is trying to acquire lock:
ffff888077aba898 (&new->rf_sem){+.+.}-{3:3}, at: __ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:428 [inline]
ffff888077aba898 (&new->rf_sem){+.+.}-{3:3}, at: ocfs2_lock_refcount_tree+0x1c0/0x980 fs/ocfs2/refcounttree.c:463

but task is already holding lock:
ffff888072340660 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x326/0x13b0 fs/ocfs2/file.c:467

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+0x44/0x2e0 kernel/locking/rwsem.c:1498
       ocfs2_read_virt_blocks+0x23f/0x8a0 fs/ocfs2/extent_map.c:984
       ocfs2_read_dir_block fs/ocfs2/dir.c:508 [inline]
       ocfs2_find_entry_el fs/ocfs2/dir.c:715 [inline]
       ocfs2_find_entry+0x3d1/0x1f90 fs/ocfs2/dir.c:1091
       ocfs2_find_files_on_disk+0xdb/0x2f0 fs/ocfs2/dir.c:1995
       ocfs2_lookup_ino_from_name+0x4f/0xf0 fs/ocfs2/dir.c:2017
       _ocfs2_get_system_file_inode fs/ocfs2/sysfile.c:136 [inline]
       ocfs2_get_system_file_inode+0x319/0x760 fs/ocfs2/sysfile.c:112
       ocfs2_init_global_system_inodes+0x316/0x650 fs/ocfs2/super.c:458
       ocfs2_initialize_super fs/ocfs2/super.c:2279 [inline]
       ocfs2_fill_super+0x3dbf/0x4d80 fs/ocfs2/super.c:995
       mount_bdev+0x287/0x3c0 fs/super.c:1400
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x24a/0xa40 fs/namespace.c:3034
       do_mount fs/namespace.c:3377 [inline]
       __do_sys_mount fs/namespace.c:3585 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3562
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #1 (&osb->system_file_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       ocfs2_get_system_file_inode+0x1b5/0x760 fs/ocfs2/sysfile.c:101
       ocfs2_reserve_suballoc_bits+0x139/0x4350 fs/ocfs2/suballoc.c:776
       ocfs2_reserve_new_metadata_blocks+0x400/0x940 fs/ocfs2/suballoc.c:978
       ocfs2_add_refcount_flag+0x36e/0xd80 fs/ocfs2/refcounttree.c:3711
       ocfs2_reflink_remap_extent fs/ocfs2/refcounttree.c:4591 [inline]
       ocfs2_reflink_remap_blocks+0xd2c/0x1930 fs/ocfs2/refcounttree.c:4718
       ocfs2_remap_file_range+0x4aa/0x720 fs/ocfs2/file.c:2706
       vfs_copy_file_range+0xce7/0x1470 fs/read_write.c:1510
       __do_sys_copy_file_range fs/read_write.c:1588 [inline]
       __se_sys_copy_file_range+0x31d/0x480 fs/read_write.c:1551
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&new->rf_sem){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
       lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       __ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:428 [inline]
       ocfs2_lock_refcount_tree+0x1c0/0x980 fs/ocfs2/refcounttree.c:463
       ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3443 [inline]
       ocfs2_refcount_cow+0x56e/0xc50 fs/ocfs2/refcounttree.c:3504
       ocfs2_cow_file_pos+0x329/0x390 fs/ocfs2/file.c:362
       ocfs2_orphan_for_truncate fs/ocfs2/file.c:383 [inline]
       ocfs2_truncate_file+0x38f/0x13b0 fs/ocfs2/file.c:496
       ocfs2_setattr+0x143b/0x1a10 fs/ocfs2/file.c:1215
       notify_change+0xbcd/0xee0 fs/attr.c:505
       do_truncate+0x197/0x220 fs/open.c:65
       vfs_truncate+0x262/0x2f0 fs/open.c:111
       do_sys_truncate+0xdc/0x190 fs/open.c:134
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

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 ***

3 locks held by syz.3.151/5005:
 #0: ffff88805e8e0460 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff8880723409c8 (&sb->s_type->i_mutex_key#28){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff8880723409c8 (&sb->s_type->i_mutex_key#28){+.+.}-{3:3}, at: do_truncate+0x183/0x220 fs/open.c:63
 #2: ffff888072340660 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x326/0x13b0 fs/ocfs2/file.c:467

stack backtrace:
CPU: 1 PID: 5005 Comm: syz.3.151 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 down_write+0x38/0x60 kernel/locking/rwsem.c:1551
 __ocfs2_lock_refcount_tree fs/ocfs2/refcounttree.c:428 [inline]
 ocfs2_lock_refcount_tree+0x1c0/0x980 fs/ocfs2/refcounttree.c:463
 ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3443 [inline]
 ocfs2_refcount_cow+0x56e/0xc50 fs/ocfs2/refcounttree.c:3504
 ocfs2_cow_file_pos+0x329/0x390 fs/ocfs2/file.c:362
 ocfs2_orphan_for_truncate fs/ocfs2/file.c:383 [inline]
 ocfs2_truncate_file+0x38f/0x13b0 fs/ocfs2/file.c:496
 ocfs2_setattr+0x143b/0x1a10 fs/ocfs2/file.c:1215
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x197/0x220 fs/open.c:65
 vfs_truncate+0x262/0x2f0 fs/open.c:111
 do_sys_truncate+0xdc/0x190 fs/open.c:134
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7748647749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f774688d038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f774889e090 RCX: 00007f7748647749
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00002000000000c0
RBP: 00007f77486cbf91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f774889e128 R14: 00007f774889e090 R15: 00007ffd0e36d0f8
 </TASK>