================================ WARNING: inconsistent lock state 5.9.0-rc5-next-20200916-syzkaller #0 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-R} -> {SOFTIRQ-ON-W} usage. syz-executor.1/18993 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff8880637b1750 ( &s->seqcount#10){+.+-}-{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_enable arch/x86/include/asm/paravirt.h:663 [inline] __local_bh_enable_ip+0x13f/0x1f0 kernel/softirq.c:200 spin_unlock_bh include/linux/spinlock.h:399 [inline] addrconf_ifdown.isra.0+0x4fe/0x1570 net/ipv6/addrconf.c:3756 addrconf_notify+0x55c/0x2310 net/ipv6/addrconf.c:3627 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2034 call_netdevice_notifiers_extack net/core/dev.c:2046 [inline] call_netdevice_notifiers net/core/dev.c:2060 [inline] rollback_registered_many+0x963/0x14f0 net/core/dev.c:9326 rollback_registered net/core/dev.c:9371 [inline] unregister_netdevice_queue+0x2dd/0x570 net/core/dev.c:10452 unregister_netdevice include/linux/netdevice.h:2797 [inline] ppp_release+0x216/0x240 drivers/net/ppp/ppp_generic.c:403 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:141 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:163 [inline] exit_to_user_mode_prepare+0x1e2/0x1f0 kernel/entry/common.c:190 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:265 entry_SYSCALL_64_after_hwframe+0x44/0xa9 irq event stamp: 125 hardirqs last enabled at (125): [] __local_bh_enable_ip+0x10f/0x1f0 kernel/softirq.c:200 hardirqs last disabled at (123): [] __local_bh_enable_ip+0x154/0x1f0 kernel/softirq.c:177 softirqs last enabled at (124): [] rcu_read_unlock_bh include/linux/rcupdate.h:726 [inline] softirqs last enabled at (124): [] __dev_queue_xmit+0x1a7e/0x2d10 net/core/dev.c:4164 softirqs last disabled at (120): [] __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#10); lock(&s->seqcount#10); *** DEADLOCK *** 2 locks held by syz-executor.1/18993: #0: ffff8880637b1ae8 (&net->xfrm.xfrm_cfg_mutex){+.+.}-{3:3}, at: xfrm_netlink_rcv+0x5c/0x90 net/xfrm/xfrm_user.c:2691 #1: ffff8880637b1798 (&(&net->xfrm.policy_hthresh.lock)->lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] #1: ffff8880637b1798 (&(&net->xfrm.policy_hthresh.lock)->lock){+.+.}-{2:2}, at: write_seqlock include/linux/seqlock.h:882 [inline] #1: ffff8880637b1798 (&(&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: 18993 Comm: syz-executor.1 Not tainted 5.9.0-rc5-next-20200916-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:00007f9b9d916c78 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: 00007ffd4dc5a9cf R14: 00007f9b9d9179c0 R15: 000000000118cf4c