[ 86.660338][ T26] audit: type=1800 audit(1582531398.814:26): pid=9625 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 87.543278][ T26] kauditd_printk_skb: 2 callbacks suppressed [ 87.543289][ T26] audit: type=1800 audit(1582531399.744:29): pid=9625 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2432 res=0 [ 87.570487][ T26] audit: type=1800 audit(1582531399.744:30): pid=9625 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2423 res=0 Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.1.22' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 97.057917][ T9778] [ 97.060300][ T9778] ====================================================== [ 97.067314][ T9778] WARNING: possible circular locking dependency detected [ 97.074326][ T9778] 5.6.0-rc2-syzkaller #0 Not tainted [ 97.079688][ T9778] ------------------------------------------------------ [ 97.087062][ T9778] syz-executor928/9778 is trying to acquire lock: [ 97.093479][ T9778] ffff8880958112a0 (&tty->termios_rwsem){++++}, at: n_tty_receive_buf_common+0x8a/0x2b70 [ 97.103395][ T9778] [ 97.103395][ T9778] but task is already holding lock: [ 97.110854][ T9778] ffffffff8a13cc40 (sel_lock){+.+.}, at: paste_selection+0x15a/0x4d0 [ 97.118964][ T9778] [ 97.118964][ T9778] which lock already depends on the new lock. [ 97.118964][ T9778] [ 97.129464][ T9778] [ 97.129464][ T9778] the existing dependency chain (in reverse order) is: [ 97.138606][ T9778] [ 97.138606][ T9778] -> #2 (sel_lock){+.+.}: [ 97.145266][ T9778] __mutex_lock+0x156/0x13c0 [ 97.150378][ T9778] mutex_lock_nested+0x16/0x20 [ 97.155668][ T9778] set_selection_kernel+0x39d/0x13d0 [ 97.161770][ T9778] set_selection_user+0x95/0xd9 [ 97.167139][ T9778] tioclinux+0x11c/0x480 [ 97.171917][ T9778] vt_ioctl+0x1a41/0x26c0 [ 97.176836][ T9778] tty_ioctl+0xa37/0x14f0 [ 97.181670][ T9778] ksys_ioctl+0x123/0x180 [ 97.186516][ T9778] __x64_sys_ioctl+0x73/0xb0 [ 97.191628][ T9778] do_syscall_64+0xfa/0x790 [ 97.196683][ T9778] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 97.203361][ T9778] [ 97.203361][ T9778] -> #1 (console_lock){+.+.}: [ 97.210375][ T9778] console_lock+0x47/0x80 [ 97.215317][ T9778] con_flush_chars+0x3d/0xa0 [ 97.220496][ T9778] n_tty_write+0xc85/0x1080 [ 97.225520][ T9778] tty_write+0x496/0x7f0 [ 97.230385][ T9778] __vfs_write+0x8a/0x110 [ 97.235319][ T9778] vfs_write+0x268/0x5d0 [ 97.240076][ T9778] ksys_write+0x14f/0x290 [ 97.244921][ T9778] __x64_sys_write+0x73/0xb0 [ 97.250026][ T9778] do_syscall_64+0xfa/0x790 [ 97.255033][ T9778] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 97.261433][ T9778] [ 97.261433][ T9778] -> #0 (&tty->termios_rwsem){++++}: [ 97.268895][ T9778] __lock_acquire+0x2596/0x4a00 [ 97.274258][ T9778] lock_acquire+0x190/0x410 [ 97.279275][ T9778] down_read+0x95/0x430 [ 97.284028][ T9778] n_tty_receive_buf_common+0x8a/0x2b70 [ 97.290092][ T9778] n_tty_receive_buf2+0x34/0x40 [ 97.295460][ T9778] tty_ldisc_receive_buf+0xad/0x1c0 [ 97.301501][ T9778] paste_selection+0x1ff/0x4d0 [ 97.306796][ T9778] tioclinux+0x133/0x480 [ 97.311551][ T9778] vt_ioctl+0x1a41/0x26c0 [ 97.316527][ T9778] tty_ioctl+0xa37/0x14f0 [ 97.321358][ T9778] ksys_ioctl+0x123/0x180 [ 97.326213][ T9778] __x64_sys_ioctl+0x73/0xb0 [ 97.331315][ T9778] do_syscall_64+0xfa/0x790 [ 97.336359][ T9778] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 97.343434][ T9778] [ 97.343434][ T9778] other info that might help us debug this: [ 97.343434][ T9778] [ 97.353839][ T9778] Chain exists of: [ 97.353839][ T9778] &tty->termios_rwsem --> console_lock --> sel_lock [ 97.353839][ T9778] [ 97.366536][ T9778] Possible unsafe locking scenario: [ 97.366536][ T9778] [ 97.374098][ T9778] CPU0 CPU1 [ 97.379666][ T9778] ---- ---- [ 97.385225][ T9778] lock(sel_lock); [ 97.389164][ T9778] lock(console_lock); [ 97.395824][ T9778] lock(sel_lock); [ 97.402133][ T9778] lock(&tty->termios_rwsem); [ 97.406881][ T9778] [ 97.406881][ T9778] *** DEADLOCK *** [ 97.406881][ T9778] [ 97.415119][ T9778] 3 locks held by syz-executor928/9778: [ 97.420939][ T9778] #0: ffff888095811090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 97.429880][ T9778] #1: ffff8880992b90a8 (&buf->lock){+.+.}, at: tty_buffer_lock_exclusive+0x30/0x40 [ 97.439298][ T9778] #2: ffffffff8a13cc40 (sel_lock){+.+.}, at: paste_selection+0x15a/0x4d0 [ 97.448207][ T9778] [ 97.448207][ T9778] stack backtrace: [ 97.454087][ T9778] CPU: 0 PID: 9778 Comm: syz-executor928 Not tainted 5.6.0-rc2-syzkaller #0 [ 97.462811][ T9778] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 97.472855][ T9778] Call Trace: [ 97.476367][ T9778] dump_stack+0x197/0x210 [ 97.480695][ T9778] print_circular_bug.isra.0.cold+0x163/0x172 [ 97.486851][ T9778] check_noncircular+0x32e/0x3e0 [ 97.491982][ T9778] ? print_circular_bug.isra.0+0x230/0x230 [ 97.498486][ T9778] ? alloc_list_entry+0xc0/0xc0 [ 97.503378][ T9778] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 97.509617][ T9778] ? find_first_zero_bit+0x9a/0xc0 [ 97.514860][ T9778] __lock_acquire+0x2596/0x4a00 [ 97.519930][ T9778] ? save_trace+0x49/0x830 [ 97.526015][ T9778] ? mark_held_locks+0xf0/0xf0 [ 97.531071][ T9778] lock_acquire+0x190/0x410 [ 97.535869][ T9778] ? n_tty_receive_buf_common+0x8a/0x2b70 [ 97.541581][ T9778] down_read+0x95/0x430 [ 97.545736][ T9778] ? n_tty_receive_buf_common+0x8a/0x2b70 [ 97.551642][ T9778] ? down_read_killable+0x490/0x490 [ 97.556845][ T9778] n_tty_receive_buf_common+0x8a/0x2b70 [ 97.562537][ T9778] ? paste_selection+0x15a/0x4d0 [ 97.567456][ T9778] ? mark_lock+0xc2/0x1220 [ 97.571853][ T9778] ? mutex_trylock+0x2d0/0x2d0 [ 97.576665][ T9778] ? mark_held_locks+0xa4/0xf0 [ 97.581414][ T9778] ? lockdep_hardirqs_on+0x421/0x5e0 [ 97.586874][ T9778] n_tty_receive_buf2+0x34/0x40 [ 97.591725][ T9778] tty_ldisc_receive_buf+0xad/0x1c0 [ 97.597473][ T9778] ? n_tty_receive_buf_common+0x2b70/0x2b70 [ 97.603349][ T9778] paste_selection+0x1ff/0x4d0 [ 97.608136][ T9778] ? sel_pos+0x90/0x90 [ 97.612352][ T9778] ? lock_downgrade+0x920/0x920 [ 97.617252][ T9778] ? wake_up_q+0x140/0x140 [ 97.621661][ T9778] tioclinux+0x133/0x480 [ 97.625893][ T9778] vt_ioctl+0x1a41/0x26c0 [ 97.630371][ T9778] ? complete_change_console+0x3a0/0x3a0 [ 97.636253][ T9778] ? tomoyo_execute_permission+0x4a0/0x4a0 [ 97.642065][ T9778] ? __sanitizer_cov_trace_switch+0x49/0x80 [ 97.647969][ T9778] ? tty_jobctrl_ioctl+0x50/0xd40 [ 97.653108][ T9778] ? complete_change_console+0x3a0/0x3a0 [ 97.658810][ T9778] tty_ioctl+0xa37/0x14f0 [ 97.663136][ T9778] ? tty_vhangup+0x30/0x30 [ 97.667550][ T9778] ? __sanitizer_cov_trace_const_cmp2+0x18/0x20 [ 97.673793][ T9778] ? do_vfs_ioctl+0x568/0x13b0 [ 97.678539][ T9778] ? ioctl_file_clone+0x180/0x180 [ 97.684540][ T9778] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 97.690765][ T9778] ? rcu_lockdep_current_cpu_online+0xe3/0x130 [ 97.697021][ T9778] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 97.703696][ T9778] ? tomoyo_file_ioctl+0x23/0x30 [ 97.708633][ T9778] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 97.714867][ T9778] ? security_file_ioctl+0x8d/0xc0 [ 97.719987][ T9778] ? tty_vhangup+0x30/0x30 [ 97.724429][ T9778] ksys_ioctl+0x123/0x180 [ 97.728756][ T9778] __x64_sys_ioctl+0x73/0xb0 [ 97.733363][ T9778] do_syscall_64+0xfa/0x790 [ 97.737866][ T9778] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 97.745174][ T9778] RIP: 0033:0x440269 [ 97.749616][ T9778] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 5b 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 97.769345][ T9778] RSP: 002b:00007fff53604418 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 97.778623][ T9778] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440269 [ 97.786693][ T9778] RDX: 0000000020000040 RSI: 000000000000541c RDI: 0000000000000004 [ 97.795318][ T9778] RBP: 00000000006ca018 R08: 000000000000000e R09: 00000000004002c8 [ 97.803529][ T9778] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401b5