R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f01059b5fa0 R15: 00007ffe4b78d7f8
 </TASK>
NILFS (loop6): btree level mismatch (ino=16): 1 != 5
NILFS error (device loop6): nilfs_bmap_lookup_contig: broken bmap (inode number=16)
======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc4-syzkaller #0 Not tainted
------------------------------------------------------
syz.6.108/6835 is trying to acquire lock:
ffff88801f7a6090 (&nilfs->ns_sem){++++}-{4:4}, at: nilfs_set_error fs/nilfs2/super.c:92 [inline]
ffff88801f7a6090 (&nilfs->ns_sem){++++}-{4:4}, at: __nilfs_error+0x1ca/0x4b0 fs/nilfs2/super.c:141

but task is already holding lock:
ffff88802eefa470 (&dat_lock_key){.+.+}-{4:4}, at: nilfs_get_block+0x1b1/0x8f0 fs/nilfs2/inode.c:83

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #7 (&dat_lock_key){.+.+}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       down_read+0x46/0x2e0 kernel/locking/rwsem.c:1524
       nilfs_get_block+0x1b1/0x8f0 fs/nilfs2/inode.c:83
       __block_write_begin_int+0x6b2/0x1900 fs/buffer.c:2151
       nilfs_prepare_chunk fs/nilfs2/dir.c:86 [inline]
       nilfs_set_link+0x23e/0x430 fs/nilfs2/dir.c:412
       nilfs_rename+0x332/0x820 fs/nilfs2/namei.c:410
       vfs_rename+0xb99/0xec0 fs/namei.c:5121
       do_renameat2+0x878/0xc50 fs/namei.c:5270
       __do_sys_rename fs/namei.c:5317 [inline]
       __se_sys_rename fs/namei.c:5315 [inline]
       __x64_sys_rename+0x82/0x90 fs/namei.c:5315
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (&nilfs->ns_segctor_sem){++++}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       down_read+0x46/0x2e0 kernel/locking/rwsem.c:1524
       nilfs_transaction_begin+0x365/0x710 fs/nilfs2/segment.c:221
       nilfs_rename+0x1bd/0x820 fs/nilfs2/namei.c:379
       vfs_rename+0xb99/0xec0 fs/namei.c:5121
       do_renameat2+0x878/0xc50 fs/namei.c:5270
       __do_sys_rename fs/namei.c:5317 [inline]
       __se_sys_rename fs/namei.c:5315 [inline]
       __x64_sys_rename+0x82/0x90 fs/namei.c:5315
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (sb_internal#5){.+.+}-{0:0}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       percpu_down_read include/linux/percpu-rwsem.h:52 [inline]
       __sb_start_write include/linux/fs.h:1783 [inline]
       sb_start_intwrite include/linux/fs.h:1966 [inline]
       nilfs_transaction_begin+0x268/0x710 fs/nilfs2/segment.c:218
       nilfs_page_mkwrite+0x8b0/0xc20 fs/nilfs2/file.c:95
       do_page_mkwrite+0x14a/0x310 mm/memory.c:3287
       wp_page_shared mm/memory.c:3688 [inline]
       do_wp_page+0x2626/0x5760 mm/memory.c:3907
       handle_pte_fault mm/memory.c:6013 [inline]
       __handle_mm_fault+0x1028/0x5380 mm/memory.c:6140
       handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6309
       do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1337
       handle_page_fault arch/x86/mm/fault.c:1480 [inline]
       exc_page_fault+0x68/0x110 arch/x86/mm/fault.c:1538
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

-> #4 (sb_pagefaults#3){.+.+}-{0:0}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       percpu_down_read include/linux/percpu-rwsem.h:52 [inline]
       __sb_start_write include/linux/fs.h:1783 [inline]
       sb_start_pagefault include/linux/fs.h:1948 [inline]
       nilfs_page_mkwrite+0x21e/0xc20 fs/nilfs2/file.c:57
       do_page_mkwrite+0x14a/0x310 mm/memory.c:3287
       wp_page_shared mm/memory.c:3688 [inline]
       do_wp_page+0x2626/0x5760 mm/memory.c:3907
       handle_pte_fault mm/memory.c:6013 [inline]
       __handle_mm_fault+0x1028/0x5380 mm/memory.c:6140
       handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6309
       do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1337
       handle_page_fault arch/x86/mm/fault.c:1480 [inline]
       exc_page_fault+0x68/0x110 arch/x86/mm/fault.c:1538
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

-> #3 (vm_lock){++++}-{0:0}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       __vma_enter_locked+0x182/0x380 mm/memory.c:6473
       __vma_start_write+0x1e/0x120 mm/memory.c:6497
       vma_start_write include/linux/mm.h:829 [inline]
       mprotect_fixup+0x571/0x9b0 mm/mprotect.c:670
       setup_arg_pages+0x53a/0xaa0 fs/exec.c:780
       load_elf_binary+0xb7a/0x27b0 fs/binfmt_elf.c:1019
       search_binary_handler fs/exec.c:1778 [inline]
       exec_binprm fs/exec.c:1810 [inline]
       bprm_execve+0x999/0x1440 fs/exec.c:1862
       kernel_execve+0x8f0/0x9f0 fs/exec.c:2028
       try_to_run_init_process+0x13/0x60 init/main.c:1385
       kernel_init+0xad/0x1d0 init/main.c:1513
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (&mm->mmap_lock){++++}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       __might_fault+0xcc/0x130 mm/memory.c:7151
       _copy_to_iter+0xf3/0x15a0 lib/iov_iter.c:184
       copy_page_to_iter+0xa7/0x150 lib/iov_iter.c:362
       copy_folio_to_iter include/linux/uio.h:198 [inline]
       filemap_read+0x78d/0x11d0 mm/filemap.c:2753
       blkdev_read_iter+0x30a/0x440 block/fops.c:809
       new_sync_read fs/read_write.c:489 [inline]
       vfs_read+0x4cd/0x980 fs/read_write.c:570
       ksys_read+0x145/0x250 fs/read_write.c:713
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&sb->s_type->i_mutex_key#7){++++}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       down_write+0x96/0x1f0 kernel/locking/rwsem.c:1577
       inode_lock include/linux/fs.h:867 [inline]
       set_blocksize+0x23b/0x500 block/bdev.c:203
       sb_set_blocksize block/bdev.c:224 [inline]
       sb_min_blocksize+0x119/0x210 block/bdev.c:239
       init_nilfs+0x43/0x690 fs/nilfs2/the_nilfs.c:710
       nilfs_fill_super+0x8f/0x650 fs/nilfs2/super.c:1060
       nilfs_get_tree+0x4f4/0x870 fs/nilfs2/super.c:1228
       vfs_get_tree+0x8f/0x2b0 fs/super.c:1759
       do_new_mount+0x24a/0xa40 fs/namespace.c:3884
       do_mount fs/namespace.c:4224 [inline]
       __do_sys_mount fs/namespace.c:4435 [inline]
       __se_sys_mount+0x317/0x410 fs/namespace.c:4412
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&nilfs->ns_sem){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3166 [inline]
       check_prevs_add kernel/locking/lockdep.c:3285 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3909
       __lock_acquire+0xaac/0xd20 kernel/locking/lockdep.c:5235
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       down_write+0x96/0x1f0 kernel/locking/rwsem.c:1577
       nilfs_set_error fs/nilfs2/super.c:92 [inline]
       __nilfs_error+0x1ca/0x4b0 fs/nilfs2/super.c:141
       nilfs_bmap_convert_error fs/nilfs2/bmap.c:35 [inline]
       nilfs_bmap_lookup_contig+0x13e/0x160 fs/nilfs2/bmap.c:100
       nilfs_get_block+0x1fb/0x8f0 fs/nilfs2/inode.c:84
       block_truncate_page+0x39c/0x820 fs/buffer.c:2702
       nilfs_truncate+0x26b/0x4e0 fs/nilfs2/inode.c:804
       nilfs_setattr+0x206/0x2b0 fs/nilfs2/inode.c:920
       notify_change+0xb33/0xe40 fs/attr.c:552
       do_truncate+0x19a/0x220 fs/open.c:65
       vfs_truncate+0x493/0x520 fs/open.c:115
       do_sys_truncate+0xdb/0x190 fs/open.c:138
       __do_sys_truncate fs/open.c:150 [inline]
       __se_sys_truncate fs/open.c:148 [inline]
       __x64_sys_truncate+0x5b/0x70 fs/open.c:148
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &nilfs->ns_sem --> &nilfs->ns_segctor_sem --> &dat_lock_key

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(&dat_lock_key);
                               lock(&nilfs->ns_segctor_sem);
                               lock(&dat_lock_key);
  lock(&nilfs->ns_sem);

 *** DEADLOCK ***

5 locks held by syz.6.108/6835:
 #0: ffff888032db2420 (sb_writers#18){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556
 #1: ffff88805ab25580 (&sb->s_type->i_mutex_key#25){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #1: ffff88805ab25580 (&sb->s_type->i_mutex_key#25){+.+.}-{4:4}, at: do_truncate+0x186/0x220 fs/open.c:63
 #2: ffff888032db2610 (sb_internal#5){.+.+}-{0:0}, at: nilfs_setattr+0x10f/0x2b0 fs/nilfs2/inode.c:912
 #3: ffff88801f7a62a0 (&nilfs->ns_segctor_sem){++++}-{4:4}, at: nilfs_transaction_begin+0x365/0x710 fs/nilfs2/segment.c:221
 #4: ffff88802eefa470 (&dat_lock_key){.+.+}-{4:4}, at: nilfs_get_block+0x1b1/0x8f0 fs/nilfs2/inode.c:83

stack backtrace:
CPU: 1 UID: 0 PID: 6835 Comm: syz.6.108 Not tainted 6.15.0-rc4-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2079
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2211
 check_prev_add kernel/locking/lockdep.c:3166 [inline]
 check_prevs_add kernel/locking/lockdep.c:3285 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3909
 __lock_acquire+0xaac/0xd20 kernel/locking/lockdep.c:5235
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1577
 nilfs_set_error fs/nilfs2/super.c:92 [inline]
 __nilfs_error+0x1ca/0x4b0 fs/nilfs2/super.c:141
 nilfs_bmap_convert_error fs/nilfs2/bmap.c:35 [inline]
 nilfs_bmap_lookup_contig+0x13e/0x160 fs/nilfs2/bmap.c:100
 nilfs_get_block+0x1fb/0x8f0 fs/nilfs2/inode.c:84
 block_truncate_page+0x39c/0x820 fs/buffer.c:2702
 nilfs_truncate+0x26b/0x4e0 fs/nilfs2/inode.c:804
 nilfs_setattr+0x206/0x2b0 fs/nilfs2/inode.c:920
 notify_change+0xb33/0xe40 fs/attr.c:552
 do_truncate+0x19a/0x220 fs/open.c:65
 vfs_truncate+0x493/0x520 fs/open.c:115
 do_sys_truncate+0xdb/0x190 fs/open.c:138
 __do_sys_truncate fs/open.c:150 [inline]
 __se_sys_truncate fs/open.c:148 [inline]
 __x64_sys_truncate+0x5b/0x70 fs/open.c:148
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f010578e969
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:00007f0106607038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f01059b5fa0 RCX: 00007f010578e969
RDX: 0000000000000000 RSI: 0000000000001ffd RDI: 0000200000000080
RBP: 00007f0105810ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f01059b5fa0 R15: 00007ffe4b78d7f8
 </TASK>
Remounting filesystem read-only
CPU: 1 UID: 0 PID: 6835 Comm: syz.6.108 Not tainted 6.15.0-rc4-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nilfs_btree_bad_node fs/nilfs2/btree.c:454 [inline]
 nilfs_btree_do_lookup_last fs/nilfs2/btree.c:633 [inline]
 nilfs_btree_last_key+0x491/0x620 fs/nilfs2/btree.c:1645
 nilfs_bmap_last_key+0x77/0x130 fs/nilfs2/bmap.c:214
 nilfs_truncate_bmap+0xfe/0x340 fs/nilfs2/inode.c:766
 nilfs_truncate+0x279/0x4e0 fs/nilfs2/inode.c:806
 nilfs_setattr+0x206/0x2b0 fs/nilfs2/inode.c:920
 notify_change+0xb33/0xe40 fs/attr.c:552
 do_truncate+0x19a/0x220 fs/open.c:65
 vfs_truncate+0x493/0x520 fs/open.c:115
 do_sys_truncate+0xdb/0x190 fs/open.c:138
 __do_sys_truncate fs/open.c:150 [inline]
 __se_sys_truncate fs/open.c:148 [inline]
 __x64_sys_truncate+0x5b/0x70 fs/open.c:148
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f010578e969
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:00007f0106607038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f01059b5fa0 RCX: 00007f010578e969
RDX: 0000000000000000 RSI: 0000000000001ffd RDI: 0000200000000080
RBP: 00007f0105810ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f01059b5fa0 R15: 00007ffe4b78d7f8
 </TASK>
NILFS (loop6): btree level mismatch (ino=16): 1 != 5
NILFS error (device loop6): nilfs_bmap_last_key: broken bmap (inode number=16)
NILFS (loop6): error -5 truncating bmap (ino=16)