====================================================== WARNING: possible circular locking dependency detected 4.20.0-rc6-next-20181217+ #172 Not tainted ------------------------------------------------------ syz-executor3/15285 is trying to acquire lock: 00000000341d1997 (&tbl->lock){+.-.}, at: neigh_change_state+0x1dc/0x7a0 net/core/neighbour.c:141 but task is already holding lock: 000000004f33963a (&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 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 kthread+0x35a/0x440 kernel/kthread.c:246 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 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 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-executor3/15285: #0: 00000000b7f3fa71 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77 #1: 000000004f33963a (&n->lock){++--}, at: __neigh_update+0xe6/0x1eb0 net/core/neighbour.c:1203 stack backtrace: CPU: 0 PID: 15285 Comm: syz-executor3 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:00007f67b5e91c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457669 RDX: 0000000020000000 RSI: 0000000000008955 RDI: 0000000000000004 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f67b5e926d4 R13: 00000000004c2747 R14: 00000000004d46f8 R15: 00000000ffffffff kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'rx-0' (000000003c30fba5): kobject_cleanup, parent 00000000ccbed7ff kobject: 'rx-0' (000000003c30fba5): auto cleanup 'remove' event kobject: 'rx-0' (000000003c30fba5): kobject_uevent_env kobject: 'rx-0' (000000003c30fba5): fill_kobj_path: path = '/devices/virtual/net/nr0/queues/rx-0' kobject: 'rx-0' (000000003c30fba5): auto cleanup kobject_del kobject: 'rx-0' (000000003c30fba5): calling ktype release kobject: 'rx-0': free name kobject: 'tx-0' (00000000e65dfaf7): kobject_cleanup, parent 00000000ccbed7ff kobject: 'tx-0' (00000000e65dfaf7): auto cleanup 'remove' event kobject: 'tx-0' (00000000e65dfaf7): kobject_uevent_env kobject: 'tx-0' (00000000e65dfaf7): fill_kobj_path: path = '/devices/virtual/net/nr0/queues/tx-0' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'tx-0' (00000000e65dfaf7): auto cleanup kobject_del kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'tx-0' (00000000e65dfaf7): calling ktype release kobject: 'tx-0': free name kobject: 'queues' (00000000ccbed7ff): kobject_cleanup, parent (null) kobject: 'queues' (00000000ccbed7ff): calling ktype release kobject: 'queues' (00000000ccbed7ff): kset_release kobject: 'queues': free name kobject: 'nr0' (000000005a806313): kobject_uevent_env kobject: 'nr0' (000000005a806313): fill_kobj_path: path = '/devices/virtual/net/nr0' kobject: 'nr0' (000000005a806313): kobject_cleanup, parent (null) kobject: 'nr0' (000000005a806313): calling ktype release kobject: 'nr0': free name kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'nr0' (0000000051004731): kobject_add_internal: parent: 'net', set: 'devices' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'nr0' (0000000051004731): kobject_uevent_env kobject: 'nr0' (0000000051004731): fill_kobj_path: path = '/devices/virtual/net/nr0' kobject: 'queues' (000000000f48521a): kobject_add_internal: parent: 'nr0', set: '' kobject: 'queues' (000000000f48521a): kobject_uevent_env kobject: 'queues' (000000000f48521a): kobject_uevent_env: filter function caused the event to drop! kobject: 'rx-0' (000000009b7051bd): kobject_add_internal: parent: 'queues', set: 'queues' kobject: 'rx-0' (000000009b7051bd): kobject_uevent_env kobject: 'rx-0' (000000009b7051bd): fill_kobj_path: path = '/devices/virtual/net/nr0/queues/rx-0' kobject: 'tx-0' (00000000317de0f2): kobject_add_internal: parent: 'queues', set: 'queues' kobject: 'tx-0' (00000000317de0f2): kobject_uevent_env kobject: 'tx-0' (00000000317de0f2): fill_kobj_path: path = '/devices/virtual/net/nr0/queues/tx-0' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'rx-0' (000000009b7051bd): kobject_cleanup, parent 000000000f48521a kobject: 'rx-0' (000000009b7051bd): auto cleanup 'remove' event kobject: 'rx-0' (000000009b7051bd): kobject_uevent_env kobject: 'rx-0' (000000009b7051bd): fill_kobj_path: path = '/devices/virtual/net/nr0/queues/rx-0' kobject: 'rx-0' (000000009b7051bd): auto cleanup kobject_del kobject: 'rx-0' (000000009b7051bd): calling ktype release kobject: 'rx-0': free name kobject: 'tx-0' (00000000317de0f2): kobject_cleanup, parent 000000000f48521a kobject: 'tx-0' (00000000317de0f2): auto cleanup 'remove' event kobject: 'tx-0' (00000000317de0f2): kobject_uevent_env kobject: 'tx-0' (00000000317de0f2): fill_kobj_path: path = '/devices/virtual/net/nr0/queues/tx-0' kobject: 'tx-0' (00000000317de0f2): auto cleanup kobject_del kobject: 'tx-0' (00000000317de0f2): calling ktype release kobject: 'tx-0': free name kobject: 'queues' (000000000f48521a): kobject_cleanup, parent (null) kobject: 'queues' (000000000f48521a): calling ktype release kobject: 'queues' (000000000f48521a): kset_release kobject: 'queues': free name kobject: 'nr0' (0000000051004731): kobject_uevent_env kobject: 'nr0' (0000000051004731): fill_kobj_path: path = '/devices/virtual/net/nr0' kobject: 'nr0' (0000000051004731): kobject_cleanup, parent (null) kobject: 'nr0' (0000000051004731): calling ktype release kobject: 'nr0': free name kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop5' (0000000011093772): kobject_uevent_env kobject: 'loop5' (0000000011093772): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop0' (00000000812bbe9e): kobject_uevent_env kobject: 'loop0' (00000000812bbe9e): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop1' (000000008ca416fb): kobject_uevent_env kobject: 'loop1' (000000008ca416fb): fill_kobj_path: path = '/devices/virtual/block/loop1'