============================================ WARNING: possible recursive locking detected syzkaller #0 Tainted: G L -------------------------------------------- syz.3.1863/13527 is trying to acquire lock: ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2784 [inline] ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline] ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:39 [inline] ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_sync_lower_features net/core/dev.c:10864 [inline] ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: __netdev_update_features+0x902/0x1fe0 net/core/dev.c:11034 but task is already holding lock: ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2784 [inline] ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline] ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:39 [inline] ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3303 [inline] ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: dev_ethtool+0x353/0x5d70 net/ethtool/ioctl.c:3572 and the lock comparison function returns 0: other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&dev_instance_lock_key#24); lock(&dev_instance_lock_key#24); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz.3.1863/13527: #0: ffffffff90611068 (rtnl_mutex){+.+.}-{4:4}, at: dev_ethtool+0x25a/0x5d70 net/ethtool/ioctl.c:3571 #1: ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2784 [inline] #1: ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline] #1: ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:39 [inline] #1: ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3303 [inline] #1: ffff8880397c0d40 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: dev_ethtool+0x353/0x5d70 net/ethtool/ioctl.c:3572 stack backtrace: CPU: 3 UID: 0 PID: 13527 Comm: syz.3.1863 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP 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_deadlock_bug.cold+0xbd/0xca kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain kernel/locking/lockdep.c:3895 [inline] __lock_acquire+0x12bb/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 netdev_lock include/linux/netdevice.h:2784 [inline] netdev_lock_ops include/net/netdev_lock.h:42 [inline] netdev_lock_ops include/net/netdev_lock.h:39 [inline] netdev_sync_lower_features net/core/dev.c:10864 [inline] __netdev_update_features+0x902/0x1fe0 net/core/dev.c:11034 netdev_change_features net/core/dev.c:11108 [inline] netdev_compute_master_upper_features+0x7b4/0xa50 net/core/dev.c:12863 bond_slave_netdev_event drivers/net/bonding/bond_main.c:3978 [inline] bond_netdev_event+0x434/0xcc0 drivers/net/bonding/bond_main.c:4023 notifier_call_chain+0x99/0x420 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2249 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] netdev_features_change+0x79/0xa0 net/core/dev.c:1590 __dev_ethtool net/ethtool/ioctl.c:3539 [inline] dev_ethtool+0xdc2/0x5d70 net/ethtool/ioctl.c:3572 dev_ioctl+0x63b/0x10e0 net/core/dev_ioctl.c:749 sock_do_ioctl+0x1a0/0x280 net/socket.c:1268 sock_ioctl+0x599/0x6b0 net/socket.c:1375 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:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f86d4f9c799 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:00007f86d31d5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f86d5216090 RCX: 00007f86d4f9c799 RDX: 0000200000000000 RSI: 0000000000008946 RDI: 0000000000000007 RBP: 00007f86d5032bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f86d5216128 R14: 00007f86d5216090 R15: 00007ffc9baae5a8