============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.6.9328/4602 is trying to acquire lock: ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline] ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:39 [inline] ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_sync_lower_features net/core/dev.c:10737 [inline] ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: __netdev_update_features+0x915/0x1da0 net/core/dev.c:10907 but task is already holding lock: ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline] ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:39 [inline] ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3285 [inline] ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: dev_ethtool+0x37b/0x5bc0 net/ethtool/ioctl.c:3554 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#20); lock(&dev_instance_lock_key#20); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz.6.9328/4602: #0: ffffffff900fe348 (rtnl_mutex){+.+.}-{4:4}, at: dev_ethtool+0x253/0x5bc0 net/ethtool/ioctl.c:3553 #1: ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2765 [inline] #1: ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline] #1: ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:39 [inline] #1: ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: __dev_ethtool net/ethtool/ioctl.c:3285 [inline] #1: ffff888076750d38 (&dev_instance_lock_key#20){+.+.}-{4:4}, at: dev_ethtool+0x37b/0x5bc0 net/ethtool/ioctl.c:3554 stack backtrace: CPU: 3 UID: 0 PID: 4602 Comm: syz.6.9328 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_deadlock_bug+0x1e9/0x240 kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain kernel/locking/lockdep.c:3895 [inline] __lock_acquire+0x1106/0x1c90 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760 netdev_lock include/linux/netdevice.h:2765 [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:10737 [inline] __netdev_update_features+0x915/0x1da0 net/core/dev.c:10907 netdev_change_features+0x64/0xb0 net/core/dev.c:10981 bond_compute_features+0x549/0x8d0 drivers/net/bonding/bond_main.c:1559 bond_slave_netdev_event drivers/net/bonding/bond_main.c:4031 [inline] bond_netdev_event+0x675/0xd30 drivers/net/bonding/bond_main.c:4076 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] netdev_features_change+0x79/0xa0 net/core/dev.c:1570 __dev_ethtool net/ethtool/ioctl.c:3521 [inline] dev_ethtool+0x6fb/0x5bc0 net/ethtool/ioctl.c:3554 dev_ioctl+0x290/0x1060 net/core/dev_ioctl.c:773 compat_ifr_data_ioctl net/socket.c:3451 [inline] compat_sock_ioctl_trans net/socket.c:3481 [inline] compat_sock_ioctl+0x42e/0x730 net/socket.c:3571 __do_compat_sys_ioctl fs/ioctl.c:695 [inline] __se_compat_sys_ioctl fs/ioctl.c:638 [inline] __ia32_compat_sys_ioctl+0x242/0x370 fs/ioctl.c:638 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x300 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf6ffd579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f53ed55c EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000008946 RDX: 0000000080000080 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi