================================ WARNING: inconsistent lock state 5.9.0-rc5-next-20200916-syzkaller #0 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-R} -> {SOFTIRQ-ON-W} usage. syz-executor.3/25638 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff8880676976d0 (&s->seqcount#9){+.+-}-{0:0}, at: xfrm_user_rcv_msg+0x41e/0x720 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_policy_check+0x11a3/0x2850 net/xfrm/xfrm_policy.c:3572 __xfrm_policy_check2 include/net/xfrm.h:1101 [inline] xfrm_policy_check include/net/xfrm.h:1106 [inline] xfrm4_policy_check include/net/xfrm.h:1111 [inline] icmp_rcv+0x867/0x1620 net/ipv4/icmp.c:1037 ip_protocol_deliver_rcu+0x5c/0x8a0 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x20a/0x370 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:301 [inline] NF_HOOK include/linux/netfilter.h:295 [inline] ip_local_deliver+0x1b3/0x200 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:449 [inline] ip_rcv_finish+0x1da/0x2f0 net/ipv4/ip_input.c:428 NF_HOOK include/linux/netfilter.h:301 [inline] NF_HOOK include/linux/netfilter.h:295 [inline] ip_rcv+0xaa/0xd0 net/ipv4/ip_input.c:539 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5287 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5401 process_backlog+0x2e1/0x8e0 net/core/dev.c:6286 napi_poll net/core/dev.c:6730 [inline] net_rx_action+0x587/0x1320 net/core/dev.c:6800 __do_softirq+0x203/0xab6 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 do_softirq kernel/softirq.c:343 [inline] do_softirq+0x154/0x1b0 kernel/softirq.c:330 __local_bh_enable_ip+0x196/0x1f0 kernel/softirq.c:195 local_bh_enable include/linux/bottom_half.h:32 [inline] tun_rx_batched.isra.0+0x476/0x720 drivers/net/tun.c:1486 tun_get_user+0x23bd/0x35d0 drivers/net/tun.c:1939 tun_chr_write_iter+0xba/0x160 drivers/net/tun.c:1968 call_write_iter include/linux/fs.h:1895 [inline] new_sync_write+0x426/0x650 fs/read_write.c:517 vfs_write+0x57d/0x700 fs/read_write.c:595 ksys_write+0x12d/0x250 fs/read_write.c:648 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 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+0x1a87/0x2d30 net/core/dev.c:4164 softirqs last disabled at (98): [] __dev_queue_xmit+0x1d7/0x2d30 net/core/dev.c:4072 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&s->seqcount#9); lock(&s->seqcount#9); *** DEADLOCK *** 2 locks held by syz-executor.3/25638: #0: ffff888067697a68 (&net->xfrm.xfrm_cfg_mutex){+.+.}-{3:3}, at: xfrm_netlink_rcv+0x5c/0x90 net/xfrm/xfrm_user.c:2691 #1: ffff888067697718 (&(&net->xfrm.policy_hthresh.lock)->lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] #1: ffff888067697718 (&(&net->xfrm.policy_hthresh.lock)->lock){+.+.}-{2:2}, at: write_seqlock include/linux/seqlock.h:882 [inline] #1: ffff888067697718 (&(&net->xfrm.policy_hthresh.lock)->lock){+.+.}-{2:2}, at: xfrm_set_spdinfo+0x2b8/0x660 net/xfrm/xfrm_user.c:1185 stack backtrace: CPU: 0 PID: 25638 Comm: syz-executor.3 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/0x74 kernel/locking/lockdep.c:4375 mark_usage kernel/locking/lockdep.c:4278 [inline] __lock_acquire+0x886/0x56d0 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+0x41e/0x720 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:00007f6819036c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000002cf80 RCX: 000000000045d5f9 RDX: 0000000000000000 RSI: 0000000020000380 RDI: 0000000000000003 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffeb729456f R14: 00007f68190379c0 R15: 000000000118cf4c