====================================================== WARNING: possible circular locking dependency detected 4.20.0-rc6-next-20181217+ #172 Not tainted ------------------------------------------------------ syz-executor5/7843 is trying to acquire lock: 000000005738742e (&tbl->lock){+.-.}, at: neigh_change_state+0x1dc/0x7a0 net/core/neighbour.c:141 PM: Basic memory bitmaps freed but task is already holding lock: 000000007be2f658 (&n->lock){++--}, at: __neigh_update+0xe6/0x1eb0 net/core/neighbour.c:1203 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&n->lock){++--}: __raw_write_lock include/linux/rwlock_api_smp.h:210 [inline] _raw_write_lock+0x2d/0x40 kernel/locking/spinlock.c:288 neigh_periodic_work+0x3c0/0xc30 net/core/neighbour.c:894 kobject: 'loop3' (00000000322887bf): kobject_uevent_env process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 kthread+0x35a/0x440 kernel/kthread.c:246 kobject: 'loop3' (00000000322887bf): fill_kobj_path: path = '/devices/virtual/block/loop3' ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 -> #0 (&tbl->lock){+.-.}: lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3841 __raw_write_lock_bh include/linux/rwlock_api_smp.h:203 [inline] _raw_write_lock_bh+0x31/0x40 kernel/locking/spinlock.c:312 neigh_change_state+0x1dc/0x7a0 net/core/neighbour.c:141 __neigh_update+0x478/0x1eb0 net/core/neighbour.c:1302 kobject: 'loop0' (000000001694c32f): kobject_uevent_env neigh_update+0x37/0x50 net/core/neighbour.c:1372 arp_req_set+0x54c/0xaa0 net/ipv4/arp.c:1072 arp_ioctl+0x48b/0xae0 net/ipv4/arp.c:1230 inet_ioctl+0x237/0x360 net/ipv4/af_inet.c:932 sock_do_ioctl+0xeb/0x420 net/socket.c:951 sock_ioctl+0x313/0x690 net/socket.c:1075 kobject: 'loop0' (000000001694c32f): fill_kobj_path: path = '/devices/virtual/block/loop0' vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&n->lock); lock(&tbl->lock); lock(&n->lock); lock(&tbl->lock); *** DEADLOCK *** 2 locks held by syz-executor5/7843: #0: 000000000a816ee5 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77 #1: 000000007be2f658 (&n->lock){++--}, at: __neigh_update+0xe6/0x1eb0 net/core/neighbour.c:1203 stack backtrace: CPU: 1 PID: 7843 Comm: syz-executor5 Not tainted 4.20.0-rc6-next-20181217+ #172 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x244/0x39d lib/dump_stack.c:113 print_circular_bug.isra.36.cold.58+0x1bd/0x27d kernel/locking/lockdep.c:1224 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2350 [inline] __lock_acquire+0x3399/0x4c20 kernel/locking/lockdep.c:3338 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3841 __raw_write_lock_bh include/linux/rwlock_api_smp.h:203 [inline] _raw_write_lock_bh+0x31/0x40 kernel/locking/spinlock.c:312 neigh_change_state+0x1dc/0x7a0 net/core/neighbour.c:141 __neigh_update+0x478/0x1eb0 net/core/neighbour.c:1302 neigh_update+0x37/0x50 net/core/neighbour.c:1372 arp_req_set+0x54c/0xaa0 net/ipv4/arp.c:1072 arp_ioctl+0x48b/0xae0 net/ipv4/arp.c:1230 inet_ioctl+0x237/0x360 net/ipv4/af_inet.c:932 sock_do_ioctl+0xeb/0x420 net/socket.c:951 sock_ioctl+0x313/0x690 net/socket.c:1075 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457669 Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8cf17a2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457669 RDX: 0000000020000000 RSI: 0000000000008955 RDI: 0000000000000005 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8cf17a36d4 R13: 00000000004c2747 R14: 00000000004d46f8 R15: 00000000ffffffff kobject: 'loop1' (00000000a126ed72): kobject_uevent_env kobject: 'loop1' (00000000a126ed72): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop5' (0000000084cd17d6): kobject_uevent_env PM: Marking nosave pages: [mem 0x00000000-0x00000fff] kobject: 'loop5' (0000000084cd17d6): fill_kobj_path: path = '/devices/virtual/block/loop5' PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] kobject: 'loop4' (000000002c05b978): kobject_uevent_env kobject: 'loop4' (000000002c05b978): fill_kobj_path: path = '/devices/virtual/block/loop4' PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] kobject: 'loop2' (0000000033c0c715): kobject_uevent_env kobject: 'loop2' (0000000033c0c715): fill_kobj_path: path = '/devices/virtual/block/loop2' kobject: 'loop3' (00000000322887bf): kobject_uevent_env kobject: 'loop3' (00000000322887bf): fill_kobj_path: path = '/devices/virtual/block/loop3' kobject: 'loop3' (00000000322887bf): kobject_uevent_env PM: Basic memory bitmaps created kobject: 'loop3' (00000000322887bf): fill_kobj_path: path = '/devices/virtual/block/loop3' kobject: 'loop5' (0000000084cd17d6): kobject_uevent_env kobject: 'loop5' (0000000084cd17d6): fill_kobj_path: path = '/devices/virtual/block/loop5' PM: Basic memory bitmaps freed kobject: 'loop3' (00000000322887bf): kobject_uevent_env PM: Marking nosave pages: [mem 0x00000000-0x00000fff] kobject: 'loop3' (00000000322887bf): fill_kobj_path: path = '/devices/virtual/block/loop3' PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] kobject: 'loop5' (0000000084cd17d6): kobject_uevent_env PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] kobject: 'loop5' (0000000084cd17d6): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop1' (00000000a126ed72): kobject_uevent_env kobject: 'loop1' (00000000a126ed72): fill_kobj_path: path = '/devices/virtual/block/loop1' PM: Basic memory bitmaps created PM: Basic memory bitmaps freed kobject: 'loop2' (0000000033c0c715): kobject_uevent_env kobject: 'loop2' (0000000033c0c715): fill_kobj_path: path = '/devices/virtual/block/loop2' kobject: 'loop4' (000000002c05b978): kobject_uevent_env kobject: 'loop4' (000000002c05b978): fill_kobj_path: path = '/devices/virtual/block/loop4' kobject: 'loop5' (0000000084cd17d6): kobject_uevent_env kobject: 'loop5' (0000000084cd17d6): fill_kobj_path: path = '/devices/virtual/block/loop5' PM: Marking nosave pages: [mem 0x00000000-0x00000fff] PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] kobject: 'loop3' (00000000322887bf): kobject_uevent_env kobject: 'loop3' (00000000322887bf): fill_kobj_path: path = '/devices/virtual/block/loop3' PM: Basic memory bitmaps created PM: Basic memory bitmaps freed kobject: 'loop4' (000000002c05b978): kobject_uevent_env kobject: 'loop4' (000000002c05b978): fill_kobj_path: path = '/devices/virtual/block/loop4' kobject: 'loop0' (000000001694c32f): kobject_uevent_env kobject: 'loop0' (000000001694c32f): fill_kobj_path: path = '/devices/virtual/block/loop0' PM: Marking nosave pages: [mem 0x00000000-0x00000fff] PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] kobject: 'loop3' (00000000322887bf): kobject_uevent_env kobject: 'loop3' (00000000322887bf): fill_kobj_path: path = '/devices/virtual/block/loop3' kobject: 'loop5' (0000000084cd17d6): kobject_uevent_env PM: Basic memory bitmaps created kobject: 'loop5' (0000000084cd17d6): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop0' (000000001694c32f): kobject_uevent_env kobject: 'loop0' (000000001694c32f): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop5' (0000000084cd17d6): kobject_uevent_env PM: Basic memory bitmaps freed kobject: 'loop5' (0000000084cd17d6): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop3' (00000000322887bf): kobject_uevent_env kobject: 'loop3' (00000000322887bf): fill_kobj_path: path = '/devices/virtual/block/loop3' kobject: 'loop4' (000000002c05b978): kobject_uevent_env PM: Marking nosave pages: [mem 0x00000000-0x00000fff] kobject: 'loop4' (000000002c05b978): fill_kobj_path: path = '/devices/virtual/block/loop4' PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] kobject: 'loop2' (0000000033c0c715): kobject_uevent_env kobject: 'loop2' (0000000033c0c715): fill_kobj_path: path = '/devices/virtual/block/loop2' kobject: 'loop1' (00000000a126ed72): kobject_uevent_env PM: Basic memory bitmaps created kobject: 'loop1' (00000000a126ed72): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop5' (0000000084cd17d6): kobject_uevent_env kobject: 'loop5' (0000000084cd17d6): fill_kobj_path: path = '/devices/virtual/block/loop5' PM: Basic memory bitmaps freed kobject: 'loop3' (00000000322887bf): kobject_uevent_env kobject: 'loop3' (00000000322887bf): fill_kobj_path: path = '/devices/virtual/block/loop3' kobject: 'loop5' (0000000084cd17d6): kobject_uevent_env kobject: 'loop5' (0000000084cd17d6): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop1' (00000000a126ed72): kobject_uevent_env kobject: 'loop1' (00000000a126ed72): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop2' (0000000033c0c715): kobject_uevent_env kobject: 'loop2' (0000000033c0c715): fill_kobj_path: path = '/devices/virtual/block/loop2'