============================= WARNING: suspicious RCU usage 5.16.0-rc8-syzkaller #0 Not tainted ----------------------------- include/linux/netfilter_netdev.h:97 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.0/27678: #0: ffff88801f44e120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1645 [inline] #0: ffff88801f44e120 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppoe_sendmsg+0x99/0x750 drivers/net/ppp/pppoe.c:849 #1: ffffffff8bb81240 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1e3/0x3650 net/core/dev.c:4153 stack backtrace: CPU: 1 PID: 27678 Comm: syz-executor.0 Not tainted 5.16.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nf_hook_egress include/linux/netfilter_netdev.h:97 [inline] __dev_queue_xmit+0x2ec3/0x3650 net/core/dev.c:4170 pppoe_sendmsg+0x5ce/0x750 drivers/net/ppp/pppoe.c:900 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 ____sys_sendmsg+0x331/0x810 net/socket.c:2409 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463 __sys_sendmmsg+0x195/0x470 net/socket.c:2549 __do_sys_sendmmsg net/socket.c:2578 [inline] __se_sys_sendmmsg net/socket.c:2575 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2575 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f8a12883e99 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8a111f9168 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f8a12996f60 RCX: 00007f8a12883e99 RDX: 04000000000000eb RSI: 000000002000d180 RDI: 0000000000000005 RBP: 00007f8a128ddff1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffec7f87fff R14: 00007f8a111f9300 R15: 0000000000022000