====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.51/6902 is trying to acquire lock: ffff0000d91abdc8 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_get_block+0x2bc/0x1154 fs/hfsplus/extents.c:260 but task is already holding lock: ffff0000d598c8f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0x88/0x70c fs/hfsplus/bitmap.c:35 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sbi->alloc_mutex){+.+.}-{4:4}: __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598 __mutex_lock kernel/locking/mutex.c:760 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812 hfsplus_block_allocate+0x88/0x70c fs/hfsplus/bitmap.c:35 hfsplus_file_extend+0x770/0x1388 fs/hfsplus/extents.c:466 hfsplus_get_block+0x314/0x1154 fs/hfsplus/extents.c:245 __block_write_begin_int+0x53c/0x15e8 fs/buffer.c:2145 block_write_begin fs/buffer.c:2256 [inline] cont_write_begin+0x62c/0x968 fs/buffer.c:2594 hfsplus_write_begin+0x7c/0xc4 fs/hfsplus/inode.c:48 cont_expand_zero fs/buffer.c:2522 [inline] cont_write_begin+0x26c/0x968 fs/buffer.c:2584 hfsplus_write_begin+0x7c/0xc4 fs/hfsplus/inode.c:48 generic_cont_expand_simple+0x12c/0x1fc fs/buffer.c:2485 hfsplus_setattr+0x140/0x24c fs/hfsplus/inode.c:260 notify_change+0x9a4/0xc50 fs/attr.c:552 do_truncate+0x198/0x210 fs/open.c:68 vfs_truncate+0x398/0x444 fs/open.c:118 do_sys_truncate+0xe4/0x1a8 fs/open.c:141 __do_sys_truncate fs/open.c:153 [inline] __se_sys_truncate fs/open.c:151 [inline] __arm64_sys_truncate+0x5c/0x74 fs/open.c:151 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #0 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868 __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598 __mutex_lock kernel/locking/mutex.c:760 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812 hfsplus_get_block+0x2bc/0x1154 fs/hfsplus/extents.c:260 block_read_full_folio+0x2ec/0x824 fs/buffer.c:2420 hfsplus_read_folio+0x28/0x38 fs/hfsplus/inode.c:28 filemap_read_folio+0xec/0x2f8 mm/filemap.c:2413 do_read_cache_folio+0x364/0x5bc mm/filemap.c:3957 do_read_cache_page mm/filemap.c:4023 [inline] read_cache_page+0x6c/0x160 mm/filemap.c:4032 read_mapping_page include/linux/pagemap.h:985 [inline] hfsplus_block_allocate+0xdc/0x70c fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0x770/0x1388 fs/hfsplus/extents.c:466 hfsplus_get_block+0x314/0x1154 fs/hfsplus/extents.c:245 __block_write_begin_int+0x53c/0x15e8 fs/buffer.c:2145 block_write_begin fs/buffer.c:2256 [inline] cont_write_begin+0x62c/0x968 fs/buffer.c:2594 hfsplus_write_begin+0x7c/0xc4 fs/hfsplus/inode.c:48 generic_perform_write+0x244/0x7bc mm/filemap.c:4175 __generic_file_write_iter+0xfc/0x204 mm/filemap.c:4292 generic_file_write_iter+0x10c/0x47c mm/filemap.c:4318 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x540/0xa3c fs/read_write.c:686 ksys_write+0x120/0x210 fs/read_write.c:738 __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:746 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sbi->alloc_mutex); lock(&HFSPLUS_I(inode)->extents_lock); lock(&sbi->alloc_mutex); lock(&HFSPLUS_I(inode)->extents_lock); *** DEADLOCK *** 5 locks held by syz.4.51/6902: #0: ffff0000dcf83b38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x1fc/0x2a0 fs/file.c:1232 #1: ffff0000d55e6428 (sb_writers#21){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3108 [inline] #1: ffff0000d55e6428 (sb_writers#21){.+.+}-{0:0}, at: vfs_write+0x24c/0xa3c fs/read_write.c:682 #2: ffff0000f7d6b238 (&sb->s_type->i_mutex_key#26){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #2: ffff0000f7d6b238 (&sb->s_type->i_mutex_key#26){+.+.}-{4:4}, at: generic_file_write_iter+0xdc/0x47c mm/filemap.c:4315 #3: ffff0000f7d6b048 (&hip->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x1b8/0x1388 fs/hfsplus/extents.c:455 #4: ffff0000d598c8f8 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0x88/0x70c fs/hfsplus/bitmap.c:35 stack backtrace: CPU: 1 UID: 0 PID: 6902 Comm: syz.4.51 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2043 check_noncircular+0x154/0x174 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868 __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598 __mutex_lock kernel/locking/mutex.c:760 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812 hfsplus_get_block+0x2bc/0x1154 fs/hfsplus/extents.c:260 block_read_full_folio+0x2ec/0x824 fs/buffer.c:2420 hfsplus_read_folio+0x28/0x38 fs/hfsplus/inode.c:28 filemap_read_folio+0xec/0x2f8 mm/filemap.c:2413 do_read_cache_folio+0x364/0x5bc mm/filemap.c:3957 do_read_cache_page mm/filemap.c:4023 [inline] read_cache_page+0x6c/0x160 mm/filemap.c:4032 read_mapping_page include/linux/pagemap.h:985 [inline] hfsplus_block_allocate+0xdc/0x70c fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0x770/0x1388 fs/hfsplus/extents.c:466 hfsplus_get_block+0x314/0x1154 fs/hfsplus/extents.c:245 __block_write_begin_int+0x53c/0x15e8 fs/buffer.c:2145 block_write_begin fs/buffer.c:2256 [inline] cont_write_begin+0x62c/0x968 fs/buffer.c:2594 hfsplus_write_begin+0x7c/0xc4 fs/hfsplus/inode.c:48 generic_perform_write+0x244/0x7bc mm/filemap.c:4175 __generic_file_write_iter+0xfc/0x204 mm/filemap.c:4292 generic_file_write_iter+0x10c/0x47c mm/filemap.c:4318 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x540/0xa3c fs/read_write.c:686 ksys_write+0x120/0x210 fs/read_write.c:738 __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:746 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596