[ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started Getty on tty1. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.82' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 68.391319][ T8493] netlink: 44 bytes leftover after parsing attributes in process `syz-executor522'. [ 68.401811][ T8493] [ 68.405372][ T8493] ============================= [ 68.410238][ T8493] WARNING: suspicious RCU usage [ 68.415277][ T8493] 5.9.0-syzkaller #0 Not tainted [ 68.420231][ T8493] ----------------------------- [ 68.425177][ T8493] net/openvswitch/flow_table.c:393 suspicious rcu_dereference_check() usage! [ 68.434224][ T8493] [ 68.434224][ T8493] other info that might help us debug this: [ 68.434224][ T8493] [ 68.444571][ T8493] [ 68.444571][ T8493] rcu_scheduler_active = 2, debug_locks = 1 [ 68.452906][ T8493] 1 lock held by syz-executor522/8493: [ 68.460069][ T8493] #0: ffffffff8c9af210 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 [ 68.468431][ T8493] [ 68.468431][ T8493] stack backtrace: [ 68.474793][ T8493] CPU: 1 PID: 8493 Comm: syz-executor522 Not tainted 5.9.0-syzkaller #0 [ 68.483193][ T8493] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 68.493604][ T8493] Call Trace: [ 68.497247][ T8493] dump_stack+0x107/0x163 [ 68.501575][ T8493] ovs_flow_tbl_masks_cache_resize+0x1bf/0x200 [ 68.507725][ T8493] ovs_dp_change+0x231/0x2b0 [ 68.512362][ T8493] ovs_dp_cmd_new+0x4c1/0xec0 [ 68.517085][ T8493] ? ovs_vport_cmd_new+0xc60/0xc60 [ 68.522195][ T8493] ? genl_family_rcv_msg_attrs_parse.constprop.0+0x1b7/0x280 [ 68.529566][ T8493] ? genl_family_rcv_msg_attrs_parse.constprop.0+0xaf/0x280 [ 68.537001][ T8493] genl_family_rcv_msg_doit+0x228/0x320 [ 68.542569][ T8493] ? genl_family_rcv_msg_attrs_parse.constprop.0+0x280/0x280 [ 68.549965][ T8493] ? ns_capable+0xde/0x100 [ 68.554399][ T8493] genl_rcv_msg+0x328/0x580 [ 68.558899][ T8493] ? genl_get_cmd+0x480/0x480 [ 68.563575][ T8493] ? ovs_vport_cmd_new+0xc60/0xc60 [ 68.568703][ T8493] ? lock_release+0x710/0x710 [ 68.573414][ T8493] netlink_rcv_skb+0x153/0x420 [ 68.578208][ T8493] ? genl_get_cmd+0x480/0x480 [ 68.582902][ T8493] ? netlink_ack+0xaa0/0xaa0 [ 68.587504][ T8493] genl_rcv+0x24/0x40 [ 68.591478][ T8493] netlink_unicast+0x533/0x7d0 [ 68.596420][ T8493] ? netlink_attachskb+0x810/0x810 [ 68.601546][ T8493] ? __phys_addr_symbol+0x2c/0x70 [ 68.606583][ T8493] ? __check_object_size+0x171/0x3f0 [ 68.611920][ T8493] netlink_sendmsg+0x856/0xd90 [ 68.616749][ T8493] ? netlink_unicast+0x7d0/0x7d0 [ 68.621684][ T8493] ? bpf_lsm_socket_sendmsg+0x5/0x10 [ 68.626964][ T8493] ? netlink_unicast+0x7d0/0x7d0 [ 68.631895][ T8493] sock_sendmsg+0xcf/0x120 [ 68.636330][ T8493] ____sys_sendmsg+0x6e8/0x810 [ 68.641116][ T8493] ? kernel_sendmsg+0x50/0x50 [ 68.645845][ T8493] ? do_recvmmsg+0x6c0/0x6c0 [ 68.650450][ T8493] ? fs_reclaim_release+0x90/0xd0 [ 68.655491][ T8493] ___sys_sendmsg+0xf3/0x170 [ 68.660202][ T8493] ? sendmsg_copy_msghdr+0x160/0x160 [ 68.665490][ T8493] ? lockdep_init_map_waits+0x26a/0x720 [ 68.671039][ T8493] ? lockdep_hardirqs_on_prepare+0x410/0x410 [ 68.677012][ T8493] ? percpu_counter_add_batch+0xbd/0x180 [ 68.682666][ T8493] ? find_held_lock+0x2d/0x110 [ 68.687455][ T8493] ? __fd_install+0x1b4/0x600 [ 68.693592][ T8493] ? lock_downgrade+0x6d0/0x6d0 [ 68.698446][ T8493] ? __fget_light+0x215/0x280 [ 68.703148][ T8493] __sys_sendmsg+0xe5/0x1b0 [ 68.707843][ T8493] ? __sys_sendmsg_sock+0xb0/0xb0 [ 68.712909][ T8493] ? syscall_enter_from_user_mode+0x1d/0x50 [ 68.718799][ T8493] do_syscall_64+0x2d/0x70 [ 68.723234][ T8493] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 68.729154][ T8493] RIP: 0033:0x440ad9 [ 68.733066][ T8493] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 68.752704][ T8493] RSP: 002b:00007ffff6e416d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 68.761224][ T8493] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440ad9 [ 68.769216][ T8493] RDX: 0000000000000000 RSI: 0000000020000500 RDI: 0000000000000003 [ 68.777210][ T8493] RBP: 00000000006cb018 R08: 0000000000000000 R09: 00000000004002c8 [ 68.785175][ T8493] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004022e0 [