syzbot

loop0: detected capacity change from 0 to 32768
ocfs2: Slot 0 on device (7,0) was already allocated to this node!
ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.57/4540 is trying to acquire lock:
ffff88807d789488 (&osb->system_file_mutex){+.+.}-{3:3}, at: ocfs2_get_system_file_inode+0x1a2/0x7b0 fs/ocfs2/sysfile.c:101

but task is already holding lock:
ffff8880598ddbe0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x195/0x300 fs/ocfs2/aops.c:1902

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}:
       down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520
       ocfs2_read_virt_blocks+0x265/0x950 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+0x3d1/0x20c0 fs/ocfs2/dir.c:1091
       ocfs2_find_files_on_disk+0x102/0x390 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+0x332/0x7b0 fs/ocfs2/sysfile.c:112
       ocfs2_init_global_system_inodes+0x316/0x650 fs/ocfs2/super.c:457
       ocfs2_initialize_super fs/ocfs2/super.c:2253 [inline]
       ocfs2_fill_super+0x2a32/0x4d00 fs/ocfs2/super.c:994
       mount_bdev+0x287/0x3c0 fs/super.c:1443
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
       vfs_get_tree+0x88/0x270 fs/super.c:1573
       do_new_mount+0x24a/0xa40 fs/namespace.c:3078
       do_mount fs/namespace.c:3421 [inline]
       __do_sys_mount fs/namespace.c:3629 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3606
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&osb->system_file_mutex){+.+.}-{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+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       ocfs2_get_system_file_inode+0x1a2/0x7b0 fs/ocfs2/sysfile.c:101
       ocfs2_reserve_local_alloc_bits+0xfc/0x2670 fs/ocfs2/localalloc.c:626
       ocfs2_reserve_clusters_with_limit+0x1bb/0xba0 fs/ocfs2/suballoc.c:1162
       ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1223 [inline]
       ocfs2_lock_allocators+0x2f7/0x5b0 fs/ocfs2/suballoc.c:2679
       ocfs2_extend_allocation+0x394/0x1840 fs/ocfs2/file.c:585
       ocfs2_extend_no_holes+0x20b/0x490 fs/ocfs2/file.c:1027
       ocfs2_expand_nonsparse_inode+0x15d/0x440 fs/ocfs2/aops.c:1621
       ocfs2_write_begin_nolock+0x1a80/0x4270 fs/ocfs2/aops.c:1687
       ocfs2_write_begin+0x1b8/0x300 fs/ocfs2/aops.c:1904
       generic_perform_write+0x2f7/0x5a0 mm/filemap.c:3862
       __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960
       ocfs2_file_write_iter+0x1593/0x1df0 fs/ocfs2/file.c:2469
       call_write_iter include/linux/fs.h:2265 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x44c/0x960 fs/read_write.c:584
       ksys_pwrite64 fs/read_write.c:699 [inline]
       __do_sys_pwrite64 fs/read_write.c:709 [inline]
       __se_sys_pwrite64 fs/read_write.c:706 [inline]
       __x64_sys_pwrite64+0x191/0x220 fs/read_write.c:706
       do_syscall_x64 arch/x86/entry/common.c:46 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 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(&osb->system_file_mutex);

 *** DEADLOCK ***

3 locks held by syz.0.57/4540:
 #0: ffff888079e80460 (sb_writers#13){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580
 #1: ffff8880598ddf48 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff8880598ddf48 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: ocfs2_file_write_iter+0x438/0x1df0 fs/ocfs2/file.c:2399
 #2: ffff8880598ddbe0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x195/0x300 fs/ocfs2/aops.c:1902

stack backtrace:
CPU: 0 PID: 4540 Comm: syz.0.57 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 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+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
 ocfs2_get_system_file_inode+0x1a2/0x7b0 fs/ocfs2/sysfile.c:101
 ocfs2_reserve_local_alloc_bits+0xfc/0x2670 fs/ocfs2/localalloc.c:626
 ocfs2_reserve_clusters_with_limit+0x1bb/0xba0 fs/ocfs2/suballoc.c:1162
 ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1223 [inline]
 ocfs2_lock_allocators+0x2f7/0x5b0 fs/ocfs2/suballoc.c:2679
 ocfs2_extend_allocation+0x394/0x1840 fs/ocfs2/file.c:585
 ocfs2_extend_no_holes+0x20b/0x490 fs/ocfs2/file.c:1027
 ocfs2_expand_nonsparse_inode+0x15d/0x440 fs/ocfs2/aops.c:1621
 ocfs2_write_begin_nolock+0x1a80/0x4270 fs/ocfs2/aops.c:1687
 ocfs2_write_begin+0x1b8/0x300 fs/ocfs2/aops.c:1904
 generic_perform_write+0x2f7/0x5a0 mm/filemap.c:3862
 __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960
 ocfs2_file_write_iter+0x1593/0x1df0 fs/ocfs2/file.c:2469
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x44c/0x960 fs/read_write.c:584
 ksys_pwrite64 fs/read_write.c:699 [inline]
 __do_sys_pwrite64 fs/read_write.c:709 [inline]
 __se_sys_pwrite64 fs/read_write.c:706 [inline]
 __x64_sys_pwrite64+0x191/0x220 fs/read_write.c:706
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8e94f8f749
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:00007fff914aff38 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f8e951e5fa0 RCX: 00007f8e94f8f749
RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000004
RBP: 00007f8e95013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000e7c R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8e951e5fa0 R14: 00007f8e951e5fa0 R15: 0000000000000004
 </TASK>