=============================
WARNING: suspicious RCU usage
5.13.0-syzkaller #0 Not tainted
-----------------------------
kernel/sched/core.c:9119 Illegal context switch in RCU-bh read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 0
1 lock held by syz-executor.4/20018:
 #0: 
ffffffff8d8bc5a8
 (
rtnl_mutex
){+.+.}-{3:3}
, at: devinet_ioctl+0x1b3/0x1c90 net/ipv4/devinet.c:1066

stack backtrace:
CPU: 1 PID: 20018 Comm: syz-executor.4 Not tainted 5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:96
 ___might_sleep+0x229/0x2c0 kernel/sched/core.c:9119
 get_next_corpse net/netfilter/nf_conntrack_core.c:2234 [inline]
 nf_ct_iterate_cleanup+0x16d/0x450 net/netfilter/nf_conntrack_core.c:2256
 nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2344 [inline]
 nf_ct_iterate_cleanup_net+0x290/0x3f0 net/netfilter/nf_conntrack_core.c:2328
 masq_device_event+0xae/0xe0 net/netfilter/nf_nat_masquerade.c:88
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2122
 call_netdevice_notifiers_extack net/core/dev.c:2134 [inline]
 call_netdevice_notifiers net/core/dev.c:2148 [inline]
 __dev_notify_flags+0x1da/0x2b0 net/core/dev.c:8834
 dev_change_flags+0x112/0x170 net/core/dev.c:8870
 devinet_ioctl+0x15e6/0x1c90 net/ipv4/devinet.c:1142
 inet_ioctl+0x1ea/0x330 net/ipv4/af_inet.c:971
 sock_do_ioctl+0xcb/0x2d0 net/socket.c:1087
 sock_ioctl+0x477/0x6a0 net/socket.c:1214
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl fs/ioctl.c:1055 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
 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: 0033:0x4665d9
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:00007f897ae40188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9
RDX: 0000000020000080 RSI: 0000000000008914 RDI: 0000000000000003
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 0000000000a9fb1f R14: 00007f897ae40300 R15: 0000000000022000