device syzkaller0 entered promiscuous mode ============================= WARNING: suspicious RCU usage syzkaller #0 Not tainted ----------------------------- net/sched/sch_api.c:304 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 4 locks held by syz.3.889/7173: #0: ffffffff8c31ef80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313 #1: ffff8880244c1948 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: packet_snd net/packet/af_packet.c:3094 [inline] #1: ffff8880244c1948 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: packet_sendmsg+0x3cf9/0x50b0 net/packet/af_packet.c:3125 #2: ffff8880244c1908 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline] #2: ffff8880244c1908 (&sch->q.lock){+.-.}-{2:2}, at: sch_direct_xmit+0x301/0x4a0 net/sched/sch_generic.c:357 #3: ffffffff8c31ef20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312 stack backtrace: CPU: 1 PID: 7173 Comm: syz.3.889 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 qdisc_lookup+0xa6/0x640 net/sched/sch_api.c:304 qdisc_tree_reduce_backlog+0x188/0x480 net/sched/sch_api.c:783 codel_qdisc_dequeue+0x14a6/0x2020 net/sched/sch_codel.c:99 qdisc_peek_dequeued+0x6e/0x1f0 include/net/sch_generic.h:1125 tbf_dequeue+0x7b/0xcf0 net/sched/sch_tbf.c:265 dequeue_skb net/sched/sch_generic.c:295 [inline] qdisc_restart net/sched/sch_generic.c:400 [inline] __qdisc_run+0x22f/0x14b0 net/sched/sch_generic.c:418 __dev_xmit_skb net/core/dev.c:3955 [inline] __dev_queue_xmit+0xdce/0x2e50 net/core/dev.c:4266 packet_snd net/packet/af_packet.c:3094 [inline] packet_sendmsg+0x3cf9/0x50b0 net/packet/af_packet.c:3125 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2446 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2500 __sys_sendmsg net/socket.c:2529 [inline] __do_sys_sendmsg net/socket.c:2538 [inline] __se_sys_sendmsg+0x1b7/0x2a0 net/socket.c:2536 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f2780160e59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f277e3b9028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f27803e8fa0 RCX: 00007f2780160e59 RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 0000000000000005 RBP: 00007f27801f6e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f27803e9038 R14: 00007f27803e8fa0 R15: 00007fffb69127e8