R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007faa8900a038 R14: 00007faa89009fa0 R15: 00007fff13914858 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.1.2489/13661 is trying to acquire lock: ffff888044582ae8 (kn->active#463){++++}-{0:0}, at: kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1406 but task is already holding lock: ffff888077e342c0 (&mddev->reconfig_mutex){+.+.}-{3:3}, at: mddev_lock drivers/md/md.h:543 [inline] ffff888077e342c0 (&mddev->reconfig_mutex){+.+.}-{3:3}, at: new_dev_store+0x222/0x660 drivers/md/md.c:4671 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mddev->reconfig_mutex){+.+.}-{3:3}: __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_interruptible_nested+0x17/0x20 kernel/locking/mutex.c:765 mddev_lock drivers/md/md.h:543 [inline] rdev_attr_store+0xa1/0x180 drivers/md/md.c:3701 kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2179 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 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 (kn->active#463){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3120 [inline] check_prevs_add kernel/locking/lockdep.c:3239 [inline] validate_chain kernel/locking/lockdep.c:3855 [inline] __lock_acquire+0x38f7/0x7d40 kernel/locking/lockdep.c:5120 lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737 kernfs_drain fs/kernfs/dir.c:478 [inline] __kernfs_remove+0x5da/0xcb0 fs/kernfs/dir.c:1372 kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1406 create_dir lib/kobject.c:-1 [inline] kobject_add_internal+0x986/0xcd0 lib/kobject.c:263 kobject_add_varg lib/kobject.c:398 [inline] kobject_add+0x160/0x230 lib/kobject.c:450 bind_rdev_to_array+0x809/0xd80 drivers/md/md.c:2513 new_dev_store+0x4a9/0x660 drivers/md/md.c:4695 md_attr_store+0xdd/0x130 drivers/md/md.c:5643 kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2179 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 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 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mddev->reconfig_mutex); lock(kn->active#463); lock(&mddev->reconfig_mutex); lock(kn->active#463); *** DEADLOCK *** 5 locks held by syz.1.2489/13661: #0: ffff888024a08d70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff88807f2d2460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590 #2: ffff88805f3a5888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x500 fs/kernfs/file.c:287 #3: ffff88801b190e88 (kn->active#460){++++}-{0:0}, at: kernfs_fop_write_iter+0x1fd/0x500 fs/kernfs/file.c:288 #4: ffff888077e342c0 (&mddev->reconfig_mutex){+.+.}-{3:3}, at: mddev_lock drivers/md/md.h:543 [inline] #4: ffff888077e342c0 (&mddev->reconfig_mutex){+.+.}-{3:3}, at: new_dev_store+0x222/0x660 drivers/md/md.c:4671 stack backtrace: CPU: 1 PID: 13661 Comm: syz.1.2489 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 check_noncircular+0x2f8/0x400 kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3120 [inline] check_prevs_add kernel/locking/lockdep.c:3239 [inline] validate_chain kernel/locking/lockdep.c:3855 [inline] __lock_acquire+0x38f7/0x7d40 kernel/locking/lockdep.c:5120 lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737 kernfs_drain fs/kernfs/dir.c:478 [inline] __kernfs_remove+0x5da/0xcb0 fs/kernfs/dir.c:1372 kernfs_remove+0x1d/0x30 fs/kernfs/dir.c:1406 create_dir lib/kobject.c:-1 [inline] kobject_add_internal+0x986/0xcd0 lib/kobject.c:263 kobject_add_varg lib/kobject.c:398 [inline] kobject_add+0x160/0x230 lib/kobject.c:450 bind_rdev_to_array+0x809/0xd80 drivers/md/md.c:2513 new_dev_store+0x4a9/0x660 drivers/md/md.c:4695 md_attr_store+0xdd/0x130 drivers/md/md.c:5643 kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2179 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 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 RIP: 0033:0x7faa88d83559 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:00007faa86fda028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007faa89009fa0 RCX: 00007faa88d83559 RDX: 0000000000000016 RSI: 0000200000000280 RDI: 0000000000000004 RBP: 00007faa88e1ab20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007faa8900a038 R14: 00007faa89009fa0 R15: 00007fff13914858 kobject_add_internal failed for dev-ram2 (error: -12 parent: md) md: failed to register dev-ram2 for md1