====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L Y ------------------------------------------------------ syz.4.1083/10710 is trying to acquire lock: ffff88804b6d0358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_lock drivers/md/md.h:713 [inline] ffff88804b6d0358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: array_state_store+0x174/0xcf0 drivers/md/md.c:4705 but task is already holding lock: ffff888055b11c38 (kn->active#77){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] ffff888055b11c38 (kn->active#77){++++}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (kn->active#77){++++}-{0:0}: lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 kernfs_drain+0x4eb/0x600 fs/kernfs/dir.c:534 __kernfs_remove+0x34c/0xbc0 fs/kernfs/dir.c:1578 kernfs_remove_by_name_ns+0x7c/0x120 fs/kernfs/dir.c:1796 kernfs_remove_by_name include/linux/kernfs.h:644 [inline] remove_files+0x96/0x1c0 fs/sysfs/group.c:28 sysfs_remove_group+0x8b/0x1b0 fs/sysfs/group.c:328 sysfs_remove_groups fs/sysfs/group.c:352 [inline] sysfs_remove_groups+0x60/0xb0 fs/sysfs/group.c:344 __kobject_del+0x89/0x220 lib/kobject.c:595 kobject_cleanup lib/kobject.c:680 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x348/0x640 lib/kobject.c:737 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495 process_scheduled_works kernel/workqueue.c:3578 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #3 ((work_completion)(&mddev->del_work)){+.+.}-{0:0}: lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 process_one_work+0xa32/0x1b10 kernel/workqueue.c:3471 process_scheduled_works kernel/workqueue.c:3578 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #2 ((wq_completion)md_misc){+.+.}-{0:0}: lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 touch_wq_lockdep_map+0xad/0x1c0 kernel/workqueue.c:4272 __flush_workqueue+0x131/0x1200 kernel/workqueue.c:4314 md_alloc+0x30/0x10a0 drivers/md/md.c:6334 md_alloc_and_put drivers/md/md.c:6423 [inline] md_probe drivers/md/md.c:6439 [inline] md_probe+0x73/0xf0 drivers/md/md.c:6434 blk_probe_dev+0x149/0x1e0 block/genhd.c:888 blk_request_module+0x16/0xc0 block/genhd.c:901 blkdev_get_no_open+0x9b/0xf0 block/bdev.c:870 blkdev_open+0x141/0x4f0 block/fops.c:671 do_dentry_open+0x674/0x1470 fs/open.c:1000 vfs_open_consume+0xcc/0x460 fs/open.c:1131 do_open fs/namei.c:4845 [inline] path_openat+0x1547/0x23f0 fs/namei.c:5010 do_file_open+0x20e/0x430 fs/namei.c:5039 do_sys_openat2+0x163/0x1d0 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1464 [inline] __se_sys_openat fs/open.c:1459 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1459 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (major_names_lock){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19f/0x1c10 kernel/locking/mutex.c:821 blk_probe_dev+0x28/0x1e0 block/genhd.c:885 blk_request_module+0x16/0xc0 block/genhd.c:901 blkdev_get_no_open+0x9b/0xf0 block/bdev.c:870 bdev_file_open_by_dev block/bdev.c:1091 [inline] bdev_file_open_by_dev+0x70/0x210 block/bdev.c:1079 md_import_device+0x120/0x360 drivers/md/md.c:3847 md_add_new_disk+0xdbf/0x1820 drivers/md/md.c:7656 md_ioctl+0x2be7/0x36c0 drivers/md/md.c:8499 blkdev_ioctl+0x5ad/0x6f0 block/ioctl.c:798 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&mddev->reconfig_mutex){+.+.}-{4:4}: check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209 check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288 lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19f/0x1c10 kernel/locking/mutex.c:821 mddev_lock drivers/md/md.h:713 [inline] array_state_store+0x174/0xcf0 drivers/md/md.c:4705 md_attr_store+0x1c5/0x330 drivers/md/md.c:6158 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6af/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &mddev->reconfig_mutex --> (work_completion)(&mddev->del_work) --> kn->active#77 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(kn->active#77); lock((work_completion)(&mddev->del_work)); lock(kn->active#77); lock(&mddev->reconfig_mutex); *** DEADLOCK *** locks held by syz.4.1083/10710: 5, last CPU#2: #0: ffff888040588b70 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1408 #1: ffff888037ffa460 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739 #2: ffff888037f03908 (&of->prealloc_mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x24d/0x5f0 fs/kernfs/file.c:320 #3: ffff888037f03880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336 #4: ffff888055b11c38 (kn->active#77){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #4: ffff888055b11c38 (kn->active#77){++++}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337 stack backtrace: CPU: 2 UID: 0 PID: 10710 Comm: syz.4.1083 Tainted: G L Y syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP, [Y]=FORCED_BIND Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2087 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2219 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209 check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288 lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19f/0x1c10 kernel/locking/mutex.c:821 mddev_lock drivers/md/md.h:713 [inline] array_state_store+0x174/0xcf0 drivers/md/md.c:4705 md_attr_store+0x1c5/0x330 drivers/md/md.c:6158 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6af/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f03a8b9f559 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:00007f03a9a99028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f03a8e25fa0 RCX: 00007f03a8b9f559 RDX: 0000000000000005 RSI: 0000200000000280 RDI: 0000000000000004 RBP: 00007f03a8c36b20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f03a8e26038 R14: 00007f03a8e25fa0 R15: 00007fffeac25fa8