syzbot

loop0: detected capacity change from 0 to 32768
ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
6.1.132-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor342/4402 is trying to acquire lock:
ffff888029861488 (&osb->system_file_mutex){+.+.}-{3:3}, at: ocfs2_get_system_file_inode+0x1ac/0x840 fs/ocfs2/sysfile.c:101

but task is already holding lock:
ffff8880717194a0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: __ocfs2_change_file_space+0x7f6/0xf60 fs/ocfs2/file.c:2015

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}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       down_read+0xad/0xa30 kernel/locking/rwsem.c:1520
       ocfs2_read_virt_blocks+0x2dc/0xab0 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+0x45f/0x27a0 fs/ocfs2/dir.c:1091
       ocfs2_find_files_on_disk+0x10d/0x3a0 fs/ocfs2/dir.c:1995
       ocfs2_lookup_ino_from_name+0xad/0x1e0 fs/ocfs2/dir.c:2017
       _ocfs2_get_system_file_inode fs/ocfs2/sysfile.c:136 [inline]
       ocfs2_get_system_file_inode+0x35e/0x840 fs/ocfs2/sysfile.c:112
       ocfs2_init_global_system_inodes+0x328/0x720 fs/ocfs2/super.c:457
       ocfs2_initialize_super fs/ocfs2/super.c:2250 [inline]
       ocfs2_fill_super+0x3022/0x5a60 fs/ocfs2/super.c:994
       mount_bdev+0x2c9/0x3f0 fs/super.c:1443
       legacy_get_tree+0xeb/0x180 fs/fs_context.c:632
       vfs_get_tree+0x88/0x270 fs/super.c:1573
       do_new_mount+0x2ba/0xb40 fs/namespace.c:3056
       do_mount fs/namespace.c:3399 [inline]
       __do_sys_mount fs/namespace.c:3607 [inline]
       __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3584
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 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+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       ocfs2_get_system_file_inode+0x1ac/0x840 fs/ocfs2/sysfile.c:101
       ocfs2_reserve_local_alloc_bits+0xfe/0x2a10 fs/ocfs2/localalloc.c:626
       ocfs2_reserve_clusters_with_limit+0x1b4/0xb50 fs/ocfs2/suballoc.c:1162
       ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1223 [inline]
       ocfs2_lock_allocators+0x306/0x620 fs/ocfs2/suballoc.c:2669
       ocfs2_extend_allocation+0x4e5/0x1d00 fs/ocfs2/file.c:585
       ocfs2_allocate_unwritten_extents+0x394/0x9e0 fs/ocfs2/file.c:1496
       __ocfs2_change_file_space+0x8ce/0xf60 fs/ocfs2/file.c:2023
       ocfs2_fallocate+0x2dc/0x350 fs/ocfs2/file.c:2138
       vfs_fallocate+0x547/0x6b0 fs/open.c:323
       ksys_fallocate fs/open.c:346 [inline]
       __do_sys_fallocate fs/open.c:354 [inline]
       __se_sys_fallocate fs/open.c:352 [inline]
       __x64_sys_fallocate+0xb9/0x100 fs/open.c:352
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 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-executor342/4402:
 #0: ffff8880746ce460 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3015 [inline]
 #0: ffff8880746ce460 (sb_writers#9){.+.+}-{0:0}, at: vfs_fallocate+0x4ba/0x6b0 fs/open.c:322
 #1: ffff888071719808 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff888071719808 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: __ocfs2_change_file_space+0x1fe/0xf60 fs/ocfs2/file.c:1949
 #2: ffff8880717194a0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: __ocfs2_change_file_space+0x7f6/0xf60 fs/ocfs2/file.c:2015

stack backtrace:
CPU: 1 PID: 4402 Comm: syz-executor342 Not tainted 6.1.132-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 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+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
 ocfs2_get_system_file_inode+0x1ac/0x840 fs/ocfs2/sysfile.c:101
 ocfs2_reserve_local_alloc_bits+0xfe/0x2a10 fs/ocfs2/localalloc.c:626
 ocfs2_reserve_clusters_with_limit+0x1b4/0xb50 fs/ocfs2/suballoc.c:1162
 ocfs2_reserve_clusters fs/ocfs2/suballoc.c:1223 [inline]
 ocfs2_lock_allocators+0x306/0x620 fs/ocfs2/suballoc.c:2669
 ocfs2_extend_allocation+0x4e5/0x1d00 fs/ocfs2/file.c:585
 ocfs2_allocate_unwritten_extents+0x394/0x9e0 fs/ocfs2/file.c:1496
 __ocfs2_change_file_space+0x8ce/0xf60 fs/ocfs2/file.c:2023
 ocfs2_fallocate+0x2dc/0x350 fs/ocfs2/file.c:2138
 vfs_fallocate+0x547/0x6b0 fs/open.c:323
 ksys_fallocate fs/open.c:346 [inline]
 __do_sys_fallocate fs/open.c:354 [inline]
 __se_sys_fallocate fs/open.c:352 [inline]
 __x64_sys_fallocate+0xb9/0x100 fs/open.c:352
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd629d80169
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:00007ffe490a09f8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd629d80169
RDX: 0000000000007351 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008001 R11: 0000000000000246 R12: 0000000001000000
R13: 00007ffe490a0a90 R14: 0000200000000040 R15: 0000000000000003
 </TASK>