syzbot

loop5: detected capacity change from 0 to 1024
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.5.512/6083 is trying to acquire lock:
ffff0000dc46d0f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_free+0xb8/0x47c fs/hfsplus/bitmap.c:182

but task is already holding lock:
ffff0000dd082988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x224/0x9ac fs/hfsplus/extents.c:574

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}:
       __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       hfsplus_get_block+0x2c0/0x11a0 fs/hfsplus/extents.c:260
       block_read_full_folio+0x2f4/0x980 fs/buffer.c:2271
       hfsplus_read_folio+0x28/0x38 fs/hfsplus/inode.c:28
       filemap_read_folio+0x134/0x384 mm/filemap.c:2490
       do_read_cache_folio+0x24c/0x538 mm/filemap.c:3659
       do_read_cache_page mm/filemap.c:3701 [inline]
       read_cache_page+0x6c/0x184 mm/filemap.c:3710
       read_mapping_page include/linux/pagemap.h:793 [inline]
       hfsplus_block_allocate+0xd8/0x7e4 fs/hfsplus/bitmap.c:37
       hfsplus_file_extend+0x7a0/0x13b4 fs/hfsplus/extents.c:466
       hfsplus_get_block+0x324/0x11a0 fs/hfsplus/extents.c:245
       __block_write_begin_int+0x350/0x1388 fs/buffer.c:1991
       __block_write_begin fs/buffer.c:2041 [inline]
       block_write_begin fs/buffer.c:2102 [inline]
       cont_write_begin+0x53c/0x780 fs/buffer.c:2456
       hfsplus_write_begin+0x98/0xe4 fs/hfsplus/inode.c:52
       generic_perform_write+0x234/0x4f4 mm/filemap.c:3862
       __generic_file_write_iter+0x130/0x250 mm/filemap.c:3960
       generic_file_write_iter+0xb4/0x2b0 mm/filemap.c:3989
       call_write_iter include/linux/fs.h:2265 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x3ec/0x7f0 fs/read_write.c:584
       ksys_write+0x12c/0x224 fs/read_write.c:637
       __do_sys_write fs/read_write.c:649 [inline]
       __se_sys_write fs/read_write.c:646 [inline]
       __arm64_sys_write+0x7c/0x90 fs/read_write.c:646
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

-> #0 (&sbi->alloc_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+0x2880/0x6800 kernel/locking/lockdep.c:5049
       lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662
       __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       hfsplus_block_free+0xb8/0x47c fs/hfsplus/bitmap.c:182
       hfsplus_free_extents+0x10c/0x880 fs/hfsplus/extents.c:360
       hfsplus_file_truncate+0x610/0x9ac fs/hfsplus/extents.c:589
       hfsplus_delete_inode+0x160/0x20c fs/hfsplus/inode.c:-1
       hfsplus_unlink+0x418/0x68c fs/hfsplus/dir.c:405
       vfs_unlink+0x2e0/0x4f4 fs/namei.c:4330
       do_unlinkat+0x328/0x500 fs/namei.c:4398
       __do_sys_unlinkat fs/namei.c:4441 [inline]
       __se_sys_unlinkat fs/namei.c:4434 [inline]
       __arm64_sys_unlinkat+0xe0/0xfc fs/namei.c:4434
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
       do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
       el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&HFSPLUS_I(inode)->extents_lock);
                               lock(&sbi->alloc_mutex);
                               lock(&HFSPLUS_I(inode)->extents_lock);
  lock(&sbi->alloc_mutex);

 *** DEADLOCK ***

5 locks held by syz.5.512/6083:
 #0: ffff0000f718a460 (sb_writers#28){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:402
 #1: ffff0000dd081740 (&type->i_mutex_dir_key#18/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #1: ffff0000dd081740 (&type->i_mutex_dir_key#18/1){+.+.}-{3:3}, at: do_unlinkat+0x198/0x500 fs/namei.c:4381
 #2: ffff0000dd082b80 (&sb->s_type->i_mutex_key#36){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #2: ffff0000dd082b80 (&sb->s_type->i_mutex_key#36){+.+.}-{3:3}, at: vfs_unlink+0xd0/0x4f4 fs/namei.c:4319
 #3: ffff0000dc46d198 (&sbi->vh_mutex){+.+.}-{3:3}, at: hfsplus_unlink+0x14c/0x68c fs/hfsplus/dir.c:370
 #4: ffff0000dd082988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x224/0x9ac fs/hfsplus/extents.c:574

stack backtrace:
CPU: 0 PID: 6083 Comm: syz.5.512 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call trace:
 dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2048
 check_noncircular+0x264/0x2f8 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+0x2880/0x6800 kernel/locking/lockdep.c:5049
 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662
 __mutex_lock_common+0x190/0x1f60 kernel/locking/mutex.c:603
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 hfsplus_block_free+0xb8/0x47c fs/hfsplus/bitmap.c:182
 hfsplus_free_extents+0x10c/0x880 fs/hfsplus/extents.c:360
 hfsplus_file_truncate+0x610/0x9ac fs/hfsplus/extents.c:589
 hfsplus_delete_inode+0x160/0x20c fs/hfsplus/inode.c:-1
 hfsplus_unlink+0x418/0x68c fs/hfsplus/dir.c:405
 vfs_unlink+0x2e0/0x4f4 fs/namei.c:4330
 do_unlinkat+0x328/0x500 fs/namei.c:4398
 __do_sys_unlinkat fs/namei.c:4441 [inline]
 __se_sys_unlinkat fs/namei.c:4434 [inline]
 __arm64_sys_unlinkat+0xe0/0xfc fs/namei.c:4434
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585