============================= 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 2 locks held by syz-executor.2/7329: #0: ffffffff88fab240 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x20a/0x35b0 net/core/dev.c:3808 #1: ffff888067931240 (&(&sch->q.lock)->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] #1: ffff888067931240 (&(&sch->q.lock)->rlock){+.-.}, at: __dev_xmit_skb net/core/dev.c:3506 [inline] #1: ffff888067931240 (&(&sch->q.lock)->rlock){+.-.}, at: __dev_queue_xmit+0x14b0/0x35b0 net/core/dev.c:3842 stack backtrace: CPU: 1 PID: 7329 Comm: syz-executor.2 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 packet_snd net/packet/af_packet.c:2959 [inline] packet_sendmsg+0x2571/0x6140 net/packet/af_packet.c:2984 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:657 __sys_sendto+0x262/0x380 net/socket.c:1952 __do_sys_sendto net/socket.c:1964 [inline] __se_sys_sendto net/socket.c:1960 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1960 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:00007f10c48d8c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000459a09 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000020000040 R09: 0000000000000014 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f10c48d96d4 R13: 00000000004c79f5 R14: 00000000004dd490 R15: 00000000ffffffff