====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.51/4560 is trying to acquire lock: ffff88801fc7c0f8 (&sbi->alloc_mutex){+.+.}-{3:3}, at: hfsplus_block_allocate+0x91/0x900 fs/hfsplus/bitmap.c:35 but task is already holding lock: ffff88807af52988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1b3/0x1950 fs/hfsplus/extents.c:455 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+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hfsplus_get_block+0x39b/0x1530 fs/hfsplus/extents.c:260 block_read_full_page+0x2e8/0xd10 fs/buffer.c:2290 do_read_cache_page+0x8a1/0x1030 mm/filemap.c:-1 read_mapping_page include/linux/pagemap.h:515 [inline] hfsplus_block_allocate+0xf4/0x900 fs/hfsplus/bitmap.c:37 hfsplus_file_extend+0xa8e/0x1950 fs/hfsplus/extents.c:466 hfsplus_get_block+0x40e/0x1530 fs/hfsplus/extents.c:245 __block_write_begin_int+0x54e/0x15a0 fs/buffer.c:2012 __block_write_begin fs/buffer.c:2062 [inline] block_write_begin fs/buffer.c:2122 [inline] cont_write_begin+0x58a/0x7b0 fs/buffer.c:2471 hfsplus_write_begin+0x92/0xe0 fs/hfsplus/inode.c:53 generic_perform_write+0x2aa/0x530 mm/filemap.c:3785 __generic_file_write_iter+0x25f/0x4e0 mm/filemap.c:3912 generic_file_write_iter+0xa6/0x1b0 mm/filemap.c:3944 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x712/0xd00 fs/read_write.c:594 ksys_write+0x14d/0x250 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (&sbi->alloc_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hfsplus_block_allocate+0x91/0x900 fs/hfsplus/bitmap.c:35 hfsplus_file_extend+0xa8e/0x1950 fs/hfsplus/extents.c:466 hfsplus_get_block+0x40e/0x1530 fs/hfsplus/extents.c:245 __block_write_begin_int+0x54e/0x15a0 fs/buffer.c:2012 __block_write_begin fs/buffer.c:2062 [inline] block_write_begin fs/buffer.c:2122 [inline] cont_write_begin+0x58a/0x7b0 fs/buffer.c:2471 hfsplus_write_begin+0x92/0xe0 fs/hfsplus/inode.c:53 cont_expand_zero fs/buffer.c:2398 [inline] cont_write_begin+0x26c/0x7b0 fs/buffer.c:2461 hfsplus_write_begin+0x92/0xe0 fs/hfsplus/inode.c:53 generic_cont_expand_simple+0xe9/0x190 fs/buffer.c:2362 hfsplus_setattr+0x165/0x280 fs/hfsplus/inode.c:261 notify_change+0xbcd/0xee0 fs/attr.c:505 do_truncate+0x197/0x220 fs/open.c:65 vfs_truncate+0x262/0x2f0 fs/open.c:111 do_sys_truncate+0xdc/0x190 fs/open.c:134 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 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 *** 3 locks held by syz.2.51/4560: #0: ffff88807b7fc460 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386 #1: ffff88807af52b80 (&sb->s_type->i_mutex_key#27){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline] #1: ffff88807af52b80 (&sb->s_type->i_mutex_key#27){+.+.}-{3:3}, at: do_truncate+0x183/0x220 fs/open.c:63 #2: ffff88807af52988 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1b3/0x1950 fs/hfsplus/extents.c:455 stack backtrace: CPU: 1 PID: 4560 Comm: syz.2.51 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 check_noncircular+0x274/0x310 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 kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hfsplus_block_allocate+0x91/0x900 fs/hfsplus/bitmap.c:35 hfsplus_file_extend+0xa8e/0x1950 fs/hfsplus/extents.c:466 hfsplus_get_block+0x40e/0x1530 fs/hfsplus/extents.c:245 __block_write_begin_int+0x54e/0x15a0 fs/buffer.c:2012 __block_write_begin fs/buffer.c:2062 [inline] block_write_begin fs/buffer.c:2122 [inline] cont_write_begin+0x58a/0x7b0 fs/buffer.c:2471 hfsplus_write_begin+0x92/0xe0 fs/hfsplus/inode.c:53 cont_expand_zero fs/buffer.c:2398 [inline] cont_write_begin+0x26c/0x7b0 fs/buffer.c:2461 hfsplus_write_begin+0x92/0xe0 fs/hfsplus/inode.c:53 generic_cont_expand_simple+0xe9/0x190 fs/buffer.c:2362 hfsplus_setattr+0x165/0x280 fs/hfsplus/inode.c:261 notify_change+0xbcd/0xee0 fs/attr.c:505 do_truncate+0x197/0x220 fs/open.c:65 vfs_truncate+0x262/0x2f0 fs/open.c:111 do_sys_truncate+0xdc/0x190 fs/open.c:134 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f34cf1ab749 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:00007f34cd3f1038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c RAX: ffffffffffffffda RBX: 00007f34cf402090 RCX: 00007f34cf1ab749 RDX: 0000000000000000 RSI: 00000000000077da RDI: 00002000000000c0 RBP: 00007f34cf22ff91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f34cf402128 R14: 00007f34cf402090 R15: 00007ffddbb6c8d8