============================= WARNING: suspicious RCU usage 5.3.0+ #0 Not tainted ----------------------------- include/net/sch_generic.h:492 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 5 locks held by syz-executor.1/27496: #0: ffff888090de5a60 (&pipe->mutex/1){+.+.}, at: pipe_lock_nested fs/pipe.c:63 [inline] #0: ffff888090de5a60 (&pipe->mutex/1){+.+.}, at: pipe_lock+0x6e/0x80 fs/pipe.c:71 #1: ffff8880a7436e50 (sk_lock-AF_INET){+.+.}, at: lock_sock include/net/sock.h:1522 [inline] #1: ffff8880a7436e50 (sk_lock-AF_INET){+.+.}, at: raw_sendmsg+0xb4c/0x2f10 net/ipv4/raw.c:665 #2: ffffffff88fab240 (rcu_read_lock_bh){....}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #2: ffffffff88fab240 (rcu_read_lock_bh){....}, at: ip_finish_output2+0x2dc/0x2570 net/ipv4/ip_output.c:214 #3: ffffffff88fab240 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x20a/0x35b0 net/core/dev.c:3808 #4: ffff88805fbea280 (&(&sch->q.lock)->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] #4: ffff88805fbea280 (&(&sch->q.lock)->rlock){+.-.}, at: __dev_xmit_skb net/core/dev.c:3506 [inline] #4: ffff88805fbea280 (&(&sch->q.lock)->rlock){+.-.}, at: __dev_queue_xmit+0x14b0/0x35b0 net/core/dev.c:3842 stack backtrace: CPU: 1 PID: 27496 Comm: syz-executor.1 Not tainted 5.3.0+ #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+0x172/0x1f0 lib/dump_stack.c:113 lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5438 qdisc_root include/net/sch_generic.h:492 [inline] netem_enqueue+0x1cfb/0x2d80 net/sched/sch_netem.c:479 __dev_xmit_skb net/core/dev.c:3531 [inline] __dev_queue_xmit+0x157e/0x35b0 net/core/dev.c:3842 dev_queue_xmit+0x18/0x20 net/core/dev.c:3906 neigh_resolve_output net/core/neighbour.c:1490 [inline] neigh_resolve_output+0x5a5/0x970 net/core/neighbour.c:1470 neigh_output include/net/neighbour.h:511 [inline] ip_finish_output2+0x8a5/0x2570 net/ipv4/ip_output.c:228 ip_do_fragment+0x174f/0x1c60 net/ipv4/ip_output.c:849 ip_fragment.constprop.0+0x176/0x240 net/ipv4/ip_output.c:575 __ip_finish_output net/ipv4/ip_output.c:306 [inline] __ip_finish_output+0x4bd/0xb90 net/ipv4/ip_output.c:290 ip_finish_output+0x38/0x1f0 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip_mc_output+0x292/0xf40 net/ipv4/ip_output.c:417 dst_output include/net/dst.h:436 [inline] ip_local_out+0xbb/0x190 net/ipv4/ip_output.c:125 ip_send_skb+0x42/0xf0 net/ipv4/ip_output.c:1555 ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1575 raw_sendmsg+0x13c4/0x2f10 net/ipv4/raw.c:672 inet_sendmsg+0x9e/0xe0 net/ipv4/af_inet.c:807 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:657 kernel_sendmsg+0x44/0x50 net/socket.c:677 sock_no_sendpage+0x116/0x150 net/core/sock.c:2733 inet_sendpage+0x10f/0x150 net/ipv4/af_inet.c:822 kernel_sendpage+0x92/0xf0 net/socket.c:3682 sock_sendpage+0x8b/0xc0 net/socket.c:935 pipe_to_sendpage+0x296/0x360 fs/splice.c:449 splice_from_pipe_feed fs/splice.c:500 [inline] __splice_from_pipe+0x397/0x7d0 fs/splice.c:624 splice_from_pipe+0x108/0x170 fs/splice.c:659 generic_splice_sendpage+0x3c/0x50 fs/splice.c:829 do_splice_from fs/splice.c:848 [inline] do_splice+0x708/0x1410 fs/splice.c:1155 __do_sys_splice fs/splice.c:1425 [inline] __se_sys_splice fs/splice.c:1405 [inline] __x64_sys_splice+0x2c6/0x330 fs/splice.c:1405 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a09 Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8d9d9c8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000459a09 RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000075bfc8 R08: 0000000000010005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8d9d9c96d4 R13: 00000000004c9202 R14: 00000000004df800 R15: 00000000ffffffff