====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.4.171/7621 is trying to acquire lock: ffff88802a994268 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf2/0x15e0 fs/hfs/extent.c:397 but task is already holding lock: ffff8880650740a0 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300 fs/hfs/bfind.c:-1 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&tree->tree_lock/1){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 hfs_find_init+0x18e/0x300 fs/hfs/bfind.c:-1 hfs_ext_read_extent fs/hfs/extent.c:200 [inline] hfs_extend_file+0x35c/0x15e0 fs/hfs/extent.c:401 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269 hfs_cat_create+0x20f/0x800 fs/hfs/catalog.c:104 hfs_mkdir+0x6c/0xe0 fs/hfs/dir.c:232 vfs_mkdir+0x75d/0x870 fs/namei.c:5139 do_mkdirat+0x281/0x4c0 fs/namei.c:5173 __do_sys_mkdir fs/namei.c:5200 [inline] __se_sys_mkdir fs/namei.c:5198 [inline] __x64_sys_mkdir+0x6c/0x80 fs/namei.c:5198 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&HFS_I(tree->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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 hfs_extend_file+0xf2/0x15e0 fs/hfs/extent.c:397 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269 __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121 hfs_ext_write_extent+0x17e/0x210 fs/hfs/extent.c:144 hfs_write_inode+0x117/0x960 fs/hfs/inode.c:441 write_inode fs/fs-writeback.c:1582 [inline] __writeback_single_inode+0x7e4/0x1230 fs/fs-writeback.c:1802 writeback_single_inode+0x488/0xd60 fs/fs-writeback.c:1858 write_inode_now+0x1c2/0x290 fs/fs-writeback.c:2937 hfs_file_fsync+0xa7/0x150 fs/hfs/inode.c:688 generic_write_sync include/linux/fs.h:2618 [inline] generic_file_write_iter+0x381/0x690 mm/filemap.c:4461 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x629/0xba0 fs/read_write.c:686 ksys_write+0x156/0x270 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&tree->tree_lock/1); lock(&HFS_I(tree->inode)->extents_lock); lock(&tree->tree_lock/1); lock(&HFS_I(tree->inode)->extents_lock); *** DEADLOCK *** 4 locks held by syz.4.171/7621: #0: ffff8880307b1d28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1255 #1: ffff888039292480 (sb_writers#25){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2683 [inline] #1: ffff888039292480 (sb_writers#25){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:682 #2: ffff88802a992e80 (&sb->s_type->i_mutex_key#32){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #2: ffff88802a992e80 (&sb->s_type->i_mutex_key#32){+.+.}-{4:4}, at: hfs_file_fsync+0x9d/0x150 fs/hfs/inode.c:685 #3: ffff8880650740a0 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300 fs/hfs/bfind.c:-1 stack backtrace: CPU: 1 UID: 0 PID: 7621 Comm: syz.4.171 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552 hfs_extend_file+0xf2/0x15e0 fs/hfs/extent.c:397 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269 __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121 hfs_ext_write_extent+0x17e/0x210 fs/hfs/extent.c:144 hfs_write_inode+0x117/0x960 fs/hfs/inode.c:441 write_inode fs/fs-writeback.c:1582 [inline] __writeback_single_inode+0x7e4/0x1230 fs/fs-writeback.c:1802 writeback_single_inode+0x488/0xd60 fs/fs-writeback.c:1858 write_inode_now+0x1c2/0x290 fs/fs-writeback.c:2937 hfs_file_fsync+0xa7/0x150 fs/hfs/inode.c:688 generic_write_sync include/linux/fs.h:2618 [inline] generic_file_write_iter+0x381/0x690 mm/filemap.c:4461 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x629/0xba0 fs/read_write.c:686 ksys_write+0x156/0x270 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f11c5f0aeb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f11c4124028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f11c6186180 RCX: 00007f11c5f0aeb9 RDX: 0000000000001006 RSI: 0000200000001980 RDI: 0000000000000004 RBP: 00007f11c5f78c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f11c6186218 R14: 00007f11c6186180 R15: 00007fff0fd940b8