[ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.48' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 68.625149][ T8399] IPVS: ftp: loaded support on port[0] = 21 executing program executing program executing program executing program executing program executing program [ 70.654290][ T8450] [ 70.656922][ T8450] ============================= [ 70.661781][ T8450] WARNING: suspicious RCU usage [ 70.666721][ T8450] 5.12.0-rc4-syzkaller #0 Not tainted [ 70.672106][ T8450] ----------------------------- [ 70.677029][ T8450] include/linux/skmsg.h:286 suspicious rcu_dereference_check() usage! [ 70.685353][ T8450] [ 70.685353][ T8450] other info that might help us debug this: [ 70.685353][ T8450] [ 70.695678][ T8450] [ 70.695678][ T8450] rcu_scheduler_active = 2, debug_locks = 1 [ 70.703840][ T8450] 1 lock held by syz-executor011/8450: [ 70.709338][ T8450] #0: ffff8880178765c8 (clock-AF_INET){++..}-{2:2}, at: sk_psock_drop+0x2c/0x460 [ 70.718647][ T8450] [ 70.718647][ T8450] stack backtrace: [ 70.724604][ T8450] CPU: 1 PID: 8450 Comm: syz-executor011 Not tainted 5.12.0-rc4-syzkaller #0 [ 70.733550][ T8450] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 70.743860][ T8450] Call Trace: [ 70.747146][ T8450] dump_stack+0x141/0x1d7 [ 70.751487][ T8450] udp_bpf_update_proto+0x244/0x3c0 [ 70.756700][ T8450] ? udp_bpf_recvmsg+0x770/0x770 [ 70.761653][ T8450] ? udp_sk_rx_dst_set+0xe0/0xe0 [ 70.766588][ T8450] sk_psock_drop+0xdf/0x460 [ 70.771096][ T8450] udp_bpf_recvmsg+0x607/0x770 [ 70.775974][ T8450] ? sk_udp_recvmsg+0x130/0x130 [ 70.781112][ T8450] ? aa_sk_perm+0x31b/0xab0 [ 70.785625][ T8450] inet_recvmsg+0x11b/0x5d0 [ 70.790153][ T8450] ? inet_sendpage+0x140/0x140 [ 70.794930][ T8450] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70 [ 70.801287][ T8450] ? security_socket_recvmsg+0x8f/0xc0 [ 70.806860][ T8450] sock_read_iter+0x33c/0x470 [ 70.811663][ T8450] ? ____sys_recvmsg+0x600/0x600 [ 70.816643][ T8450] ? lock_downgrade+0x6e0/0x6e0 [ 70.821512][ T8450] ? fsnotify_first_mark+0x1f0/0x1f0 [ 70.826840][ T8450] do_iter_readv_writev+0x56a/0x740 [ 70.832093][ T8450] ? new_sync_write+0x650/0x650 [ 70.836986][ T8450] do_iter_read+0x285/0x6e0 [ 70.841511][ T8450] ? import_iovec+0x10c/0x150 [ 70.846204][ T8450] vfs_readv+0xe5/0x150 [ 70.850507][ T8450] ? vfs_iter_read+0xa0/0xa0 [ 70.855135][ T8450] ? lock_downgrade+0x6e0/0x6e0 [ 70.860165][ T8450] ? __fget_files+0x288/0x3d0 [ 70.864882][ T8450] ? __fget_light+0xea/0x280 [ 70.869502][ T8450] do_readv+0x27f/0x300 [ 70.873761][ T8450] ? vfs_readv+0x150/0x150 [ 70.878221][ T8450] ? syscall_enter_from_user_mode+0x27/0x70 [ 70.884402][ T8450] do_syscall_64+0x2d/0x70 [ 70.888855][ T8450] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 70.894768][ T8450] RIP: 0033:0x445c19 [ 70.898688][ T8450] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 [ 70.918324][ T8450] RSP: 002b:00007f74d9427318 EFLAGS: 00000246 ORIG_RAX: 0000000000000013 [ 70.926761][ T8450] RAX: ffffffffffffffda RBX: 00000000004cb438 RCX: 0000000000445c19 [ 70.934744][ T8450] RDX: 0000000000000001 RSI: 0000000020000340 RDI: 0000000000000004 [ 70.942733][ T8450] RBP: 00000000004cb430 R08: 0000000000000000 R09: 0000000000000000 executing program [ 70.950726][ T8450] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049b154 [ 70.958711][ T8450] R13: 00007ffc3853ccbf R14: 00007f74d9427400 R15: 0000000000022000 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program