syzbot

loop0: detected capacity change from 0 to 32768
ocfs2: Mounting device (7,0) on (node local, slot 0) with writeback data mode.
======================================================
WARNING: possible circular locking dependency detected
6.1.141-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor468/4396 is trying to acquire lock:
ffff88801ee7d488 (&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:
ffff888070f18660 (&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:976
       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:3054
       do_mount fs/namespace.c:3397 [inline]
       __do_sys_mount fs/namespace.c:3605 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3582
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       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_suballoc_bits+0x135/0x4630 fs/ocfs2/suballoc.c:776
       ocfs2_reserve_cluster_bitmap_bits fs/ocfs2/suballoc.c:1128 [inline]
       ocfs2_reserve_clusters_with_limit+0x2f8/0xba0 fs/ocfs2/suballoc.c:1173
       ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1223 [inline]
       ocfs2_lock_allocators+0x2f7/0x5b0 fs/ocfs2/suballoc.c:2669
       ocfs2_write_begin_nolock+0x2286/0x4270 fs/ocfs2/aops.c:1740
       ocfs2_write_begin+0x1b8/0x300 fs/ocfs2/aops.c:1904
       generic_perform_write+0x2db/0x560 mm/filemap.c:3846
       __generic_file_write_iter+0x172/0x430 mm/filemap.c:3974
       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:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       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-executor468/4396:
 #0: ffff888024b42460 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580
 #1: ffff888070f189c8 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff888070f189c8 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: ocfs2_file_write_iter+0x438/0x1df0 fs/ocfs2/file.c:2399
 #2: ffff888070f18660 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_write_begin+0x195/0x300 fs/ocfs2/aops.c:1902

stack backtrace:
CPU: 0 PID: 4396 Comm: syz-executor468 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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_suballoc_bits+0x135/0x4630 fs/ocfs2/suballoc.c:776
 ocfs2_reserve_cluster_bitmap_bits fs/ocfs2/suballoc.c:1128 [inline]
 ocfs2_reserve_clusters_with_limit+0x2f8/0xba0 fs/ocfs2/suballoc.c:1173
 ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1223 [inline]
 ocfs2_lock_allocators+0x2f7/0x5b0 fs/ocfs2/suballoc.c:2669
 ocfs2_write_begin_nolock+0x2286/0x4270 fs/ocfs2/aops.c:1740
 ocfs2_write_begin+0x1b8/0x300 fs/ocfs2/aops.c:1904
 generic_perform_write+0x2db/0x560 mm/filemap.c:3846
 __generic_file_write_iter+0x172/0x430 mm/filemap.c:3974
 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:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3e1511d1a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdee2f9db8 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3e1511d1a9
RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000009000 R11: 0000000000000246 R12: 0000000001000000
R13: 00007ffdee2f9e50 R14: 0000200000000040 R15: 0000000000000003
 </TASK>