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
5.15.180-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor336/4306 is trying to acquire lock:
ffff88802a981488 (&osb->system_file_mutex){+.+.}-{3:3}, at: ocfs2_get_system_file_inode+0x1a1/0x7b0 fs/ocfs2/sysfile.c:101

but task is already holding lock:
ffff88806f4a22e0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_page_mkwrite+0x301/0xbd0 fs/ocfs2/mmap.c:142

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+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_read+0x45/0x2e0 kernel/locking/rwsem.c:1498
       ocfs2_read_virt_blocks+0x2b3/0xa10 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+0x433/0x2550 fs/ocfs2/dir.c:1091
       ocfs2_find_files_on_disk+0xea/0x310 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+0x314/0x7b0 fs/ocfs2/sysfile.c:112
       ocfs2_init_global_system_inodes+0x328/0x720 fs/ocfs2/super.c:458
       ocfs2_initialize_super fs/ocfs2/super.c:2276 [inline]
       ocfs2_fill_super+0x47b3/0x5890 fs/ocfs2/super.c:995
       mount_bdev+0x2c9/0x3f0 fs/super.c:1400
       legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
       do_mount fs/namespace.c:3355 [inline]
       __do_sys_mount fs/namespace.c:3563 [inline]
       __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0x80 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&osb->system_file_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 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+0x1a1/0x7b0 fs/ocfs2/sysfile.c:101
       ocfs2_reserve_local_alloc_bits+0x103/0x27a0 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_write_begin_nolock+0x28e5/0x4d20 fs/ocfs2/aops.c:1741
       __ocfs2_page_mkwrite fs/ocfs2/mmap.c:93 [inline]
       ocfs2_page_mkwrite+0x65f/0xbd0 fs/ocfs2/mmap.c:144
       do_page_mkwrite+0x1a9/0x440 mm/memory.c:2922
       do_shared_fault mm/memory.c:4328 [inline]
       do_fault mm/memory.c:4396 [inline]
       handle_pte_fault mm/memory.c:4650 [inline]
       __handle_mm_fault mm/memory.c:4785 [inline]
       handle_mm_fault+0x2803/0x5960 mm/memory.c:4883
       do_user_addr_fault arch/x86/mm/fault.c:1357 [inline]
       handle_page_fault arch/x86/mm/fault.c:1445 [inline]
       exc_page_fault+0x271/0x700 arch/x86/mm/fault.c:1501
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606

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-executor336/4306:
 #0: ffff8880762e1d28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock+0x1c/0x50 include/linux/mmap_lock.h:117
 #1: ffff88807bf38558 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x1a9/0x440 mm/memory.c:2922
 #2: ffff88806f4a22e0 (&ocfs2_file_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_page_mkwrite+0x301/0xbd0 fs/ocfs2/mmap.c:142

stack backtrace:
CPU: 0 PID: 4306 Comm: syz-executor336 Not tainted 5.15.180-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+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 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+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1da/0x25a0 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+0x1a1/0x7b0 fs/ocfs2/sysfile.c:101
 ocfs2_reserve_local_alloc_bits+0x103/0x27a0 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_write_begin_nolock+0x28e5/0x4d20 fs/ocfs2/aops.c:1741
 __ocfs2_page_mkwrite fs/ocfs2/mmap.c:93 [inline]
 ocfs2_page_mkwrite+0x65f/0xbd0 fs/ocfs2/mmap.c:144
 do_page_mkwrite+0x1a9/0x440 mm/memory.c:2922
 do_shared_fault mm/memory.c:4328 [inline]
 do_fault mm/memory.c:4396 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x2803/0x5960 mm/memory.c:4883
 do_user_addr_fault arch/x86/mm/fault.c:1357 [inline]
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x271/0x700 arch/x86/mm/fault.c:1501
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f2975088d1f
Code: bf 09 00 00 00 e8 d1 44 03 00 48 8b 35 f2 03 0b 00 ba 7a c1 00 00 31 c0 bf 4d 00 00 00 e8 b9 44 03 00 31 f6 31 d2 31 c9 31 ff <48> 89 13 31 c0 48 89 da 89 4b 08 31 c9 48 89 73 10 48 89 73 18 48
RSP: 002b:00007ffe8a023c40 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000200000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000001000000
R13: 00007ffe8a023ce0 R14: 0000200000000040 R15: 0000000000000003
 </TASK>