================================ WARNING: inconsistent lock state 5.9.0-rc5-next-20200915-syzkaller #0 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-R} -> {SOFTIRQ-ON-W} usage. syz-executor.0/15304 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff88805da556d0 (&s->seqcount#11){+.+-}-{0:0}, at: xfrm_user_rcv_msg+0x414/0x700 net/xfrm/xfrm_user.c:2684 {IN-SOFTIRQ-R} state was registered at: lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 seqcount_lockdep_reader_access+0x139/0x1a0 include/linux/seqlock.h:103 xfrm_policy_lookup_inexact_addr+0x57/0x200 net/xfrm/xfrm_policy.c:1909 xfrm_policy_find_inexact_candidates+0xac/0x1d0 net/xfrm/xfrm_policy.c:1953 xfrm_policy_lookup_bytype+0x4b8/0xa40 net/xfrm/xfrm_policy.c:2108 xfrm_policy_lookup net/xfrm/xfrm_policy.c:2144 [inline] xfrm_bundle_lookup net/xfrm/xfrm_policy.c:2944 [inline] xfrm_lookup_with_ifid+0xaa1/0x2100 net/xfrm/xfrm_policy.c:3085 icmp6_dst_alloc+0x489/0x6c0 net/ipv6/route.c:3187 ndisc_send_skb+0x1207/0x1720 net/ipv6/ndisc.c:486 ndisc_send_rs+0x12e/0x700 net/ipv6/ndisc.c:700 addrconf_rs_timer+0x2ec/0x7c0 net/ipv6/addrconf.c:3873 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1413 expire_timers kernel/time/timer.c:1458 [inline] __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 __do_softirq+0x202/0xa42 kernel/softirq.c:298 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:786 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x235/0x280 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631 arch_local_irq_restore+0x2e/0x50 arch/x86/include/asm/paravirt.h:653 lock_is_held_type+0xbb/0xf0 kernel/locking/lockdep.c:5439 lock_is_held include/linux/lockdep.h:271 [inline] schedule_debug kernel/sched/core.c:4296 [inline] __schedule+0x133a/0x21b0 kernel/sched/core.c:4421 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:4685 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:40 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x78/0x90 kernel/locking/spinlock.c:191 spin_unlock_irqrestore include/linux/spinlock.h:409 [inline] pty_write+0x15a/0x1f0 drivers/tty/pty.c:123 tty_put_char+0x122/0x150 drivers/tty/tty_io.c:3030 __process_echoes+0x577/0x9f0 drivers/tty/n_tty.c:728 commit_echoes+0x148/0x210 drivers/tty/n_tty.c:794 n_tty_receive_char_fast drivers/tty/n_tty.c:1449 [inline] n_tty_receive_buf_fast drivers/tty/n_tty.c:1609 [inline] __receive_buf drivers/tty/n_tty.c:1644 [inline] n_tty_receive_buf_common+0x203f/0x2bc0 drivers/tty/n_tty.c:1742 tty_ldisc_receive_buf+0xa9/0x190 drivers/tty/tty_buffer.c:461 tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:481 [inline] flush_to_ldisc+0x20d/0x380 drivers/tty/tty_buffer.c:533 process_one_work+0x933/0x15a0 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3af/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 irq event stamp: 103 hardirqs last enabled at (103): [] __local_bh_enable_ip+0x10f/0x1f0 kernel/softirq.c:200 hardirqs last disabled at (101): [] __local_bh_enable_ip+0x154/0x1f0 kernel/softirq.c:177 softirqs last enabled at (102): [] rcu_read_unlock_bh include/linux/rcupdate.h:726 [inline] softirqs last enabled at (102): [] __dev_queue_xmit+0x1a7e/0x2d10 net/core/dev.c:4164 softirqs last disabled at (98): [] __dev_queue_xmit+0x1d7/0x2d10 net/core/dev.c:4072 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&s->seqcount#11); lock(&s->seqcount#11); *** DEADLOCK *** 2 locks held by syz-executor.0/15304: #0: ffff88805da55a68 (&net->xfrm.xfrm_cfg_mutex){+.+.}-{3:3}, at: xfrm_netlink_rcv+0x5c/0x90 net/xfrm/xfrm_user.c:2691 #1: ffff88805da55718 (&(&net->xfrm.policy_hthresh.lock)->lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] (&(&net->xfrm.policy_hthresh.lock)->lock){+.+.}-{2:2}, at: write_seqlock include/linux/seqlock.h:882 [inline] (&(&net->xfrm.policy_hthresh.lock)->lock){+.+.}-{2:2}, at: xfrm_set_spdinfo+0x2b8/0x660 net/xfrm/xfrm_user.c:1185 stack backtrace: CPU: 1 PID: 15304 Comm: syz-executor.0 Not tainted 5.9.0-rc5-next-20200915-syzkaller #0 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+0x198/0x1fb lib/dump_stack.c:118 print_usage_bug kernel/locking/lockdep.c:4377 [inline] valid_state kernel/locking/lockdep.c:3705 [inline] mark_lock_irq kernel/locking/lockdep.c:3914 [inline] mark_lock.cold+0x6f/0x10d kernel/locking/lockdep.c:4375 mark_usage kernel/locking/lockdep.c:4278 [inline] __lock_acquire+0x882/0x55d0 kernel/locking/lockdep.c:4750 lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398 write_seqcount_t_begin_nested include/linux/seqlock.h:509 [inline] write_seqcount_t_begin include/linux/seqlock.h:535 [inline] write_seqlock include/linux/seqlock.h:883 [inline] xfrm_set_spdinfo+0x302/0x660 net/xfrm/xfrm_user.c:1185 xfrm_user_rcv_msg+0x414/0x700 net/xfrm/xfrm_user.c:2684 netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470 xfrm_netlink_rcv+0x6b/0x90 net/xfrm/xfrm_user.c:2692 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:671 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2362 ___sys_sendmsg+0xf3/0x170 net/socket.c:2416 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2449 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5f9 Code: 5d b4 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f344c600c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000002cf80 RCX: 000000000045d5f9 RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffd3e830a1f R14: 00007f344c6019c0 R15: 000000000118cf4c