Warning: Permanently added '10.128.10.37' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 91.098696][ T9784] [ 91.101164][ T9784] ====================================================== [ 91.108201][ T9784] WARNING: possible circular locking dependency detected [ 91.115207][ T9784] 5.6.0-rc2-next-20200221-syzkaller #0 Not tainted [ 91.121682][ T9784] ------------------------------------------------------ [ 91.128774][ T9784] syz-executor343/9784 is trying to acquire lock: [ 91.135219][ T9784] ffff8880985822a0 (&tty->termios_rwsem){++++}, at: n_tty_receive_buf_common+0x8a/0x2b70 [ 91.145014][ T9784] [ 91.145014][ T9784] but task is already holding lock: [ 91.152483][ T9784] ffffffff8a140800 (sel_lock){+.+.}, at: paste_selection+0x15a/0x4d0 [ 91.160793][ T9784] [ 91.160793][ T9784] which lock already depends on the new lock. [ 91.160793][ T9784] [ 91.171208][ T9784] [ 91.171208][ T9784] the existing dependency chain (in reverse order) is: [ 91.180203][ T9784] [ 91.180203][ T9784] -> #2 (sel_lock){+.+.}: [ 91.186722][ T9784] __mutex_lock+0x156/0x13c0 [ 91.191821][ T9784] mutex_lock_nested+0x16/0x20 [ 91.197134][ T9784] set_selection_kernel+0x39d/0x13d0 [ 91.202923][ T9784] set_selection_user+0x95/0xd9 [ 91.208294][ T9784] tioclinux+0x11c/0x480 [ 91.213047][ T9784] vt_ioctl+0x1a41/0x26c0 [ 91.219023][ T9784] tty_ioctl+0xa37/0x14f0 [ 91.223899][ T9784] ksys_ioctl+0x123/0x180 [ 91.228728][ T9784] __x64_sys_ioctl+0x73/0xb0 [ 91.233828][ T9784] do_syscall_64+0xfa/0x790 [ 91.238871][ T9784] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 91.245368][ T9784] [ 91.245368][ T9784] -> #1 (console_lock){+.+.}: [ 91.252219][ T9784] console_lock+0x47/0x80 [ 91.257172][ T9784] con_flush_chars+0x3d/0xa0 [ 91.262293][ T9784] n_tty_write+0xc85/0x1080 [ 91.267381][ T9784] tty_write+0x496/0x7f0 [ 91.272132][ T9784] __vfs_write+0x8a/0x110 [ 91.276999][ T9784] vfs_write+0x268/0x5d0 [ 91.281746][ T9784] ksys_write+0x14f/0x290 [ 91.286581][ T9784] __x64_sys_write+0x73/0xb0 [ 91.291766][ T9784] do_syscall_64+0xfa/0x790 [ 91.296772][ T9784] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 91.303317][ T9784] [ 91.303317][ T9784] -> #0 (&tty->termios_rwsem){++++}: [ 91.310765][ T9784] __lock_acquire+0x29cd/0x6320 [ 91.316131][ T9784] lock_acquire+0x190/0x410 [ 91.321162][ T9784] down_read+0x95/0x440 [ 91.325821][ T9784] n_tty_receive_buf_common+0x8a/0x2b70 [ 91.331881][ T9784] n_tty_receive_buf2+0x34/0x40 [ 91.337363][ T9784] tty_ldisc_receive_buf+0xad/0x1c0 [ 91.343067][ T9784] paste_selection+0x1ff/0x4d0 [ 91.348334][ T9784] tioclinux+0x133/0x480 [ 91.353081][ T9784] vt_ioctl+0x1a41/0x26c0 [ 91.357937][ T9784] tty_ioctl+0xa37/0x14f0 [ 91.362770][ T9784] ksys_ioctl+0x123/0x180 [ 91.367604][ T9784] __x64_sys_ioctl+0x73/0xb0 [ 91.372800][ T9784] do_syscall_64+0xfa/0x790 [ 91.377809][ T9784] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 91.384209][ T9784] [ 91.384209][ T9784] other info that might help us debug this: [ 91.384209][ T9784] [ 91.394867][ T9784] Chain exists of: [ 91.394867][ T9784] &tty->termios_rwsem --> console_lock --> sel_lock [ 91.394867][ T9784] [ 91.408399][ T9784] Possible unsafe locking scenario: [ 91.408399][ T9784] [ 91.415834][ T9784] CPU0 CPU1 [ 91.421180][ T9784] ---- ---- [ 91.426554][ T9784] lock(sel_lock); [ 91.430375][ T9784] lock(console_lock); [ 91.437173][ T9784] lock(sel_lock); [ 91.443603][ T9784] lock(&tty->termios_rwsem); [ 91.448349][ T9784] [ 91.448349][ T9784] *** DEADLOCK *** [ 91.448349][ T9784] [ 91.457512][ T9784] 3 locks held by syz-executor343/9784: [ 91.463039][ T9784] #0: ffff888098582090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 [ 91.471970][ T9784] #1: ffff8880aa5be0a8 (&buf->lock){+.+.}, at: tty_buffer_lock_exclusive+0x30/0x40 [ 91.481401][ T9784] #2: ffffffff8a140800 (sel_lock){+.+.}, at: paste_selection+0x15a/0x4d0 [ 91.489893][ T9784] [ 91.489893][ T9784] stack backtrace: [ 91.495908][ T9784] CPU: 0 PID: 9784 Comm: syz-executor343 Not tainted 5.6.0-rc2-next-20200221-syzkaller #0 [ 91.505778][ T9784] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 91.515834][ T9784] Call Trace: [ 91.519126][ T9784] dump_stack+0x197/0x210 [ 91.523459][ T9784] print_circular_bug.isra.0.cold+0x163/0x172 [ 91.529511][ T9784] check_noncircular+0x32e/0x3e0 [ 91.534434][ T9784] ? print_circular_bug.isra.0+0x230/0x230 [ 91.540220][ T9784] ? alloc_list_entry+0xc0/0xc0 [ 91.545088][ T9784] ? mark_lock+0xc2/0x1220 [ 91.549488][ T9784] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 91.555790][ T9784] ? find_first_zero_bit+0x9a/0xc0 [ 91.560888][ T9784] __lock_acquire+0x29cd/0x6320 [ 91.565787][ T9784] ? save_trace+0x49/0x830 [ 91.570973][ T9784] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 91.577258][ T9784] ? mark_held_locks+0xf0/0xf0 [ 91.582008][ T9784] lock_acquire+0x190/0x410 [ 91.586545][ T9784] ? n_tty_receive_buf_common+0x8a/0x2b70 [ 91.592285][ T9784] down_read+0x95/0x440 [ 91.596423][ T9784] ? n_tty_receive_buf_common+0x8a/0x2b70 [ 91.602273][ T9784] ? down_read_killable+0x490/0x490 [ 91.607494][ T9784] n_tty_receive_buf_common+0x8a/0x2b70 [ 91.613034][ T9784] ? paste_selection+0x15a/0x4d0 [ 91.617963][ T9784] ? mark_lock+0xc2/0x1220 [ 91.622402][ T9784] ? mutex_trylock+0x2d0/0x2d0 [ 91.627150][ T9784] ? mark_held_locks+0xa4/0xf0 [ 91.631972][ T9784] ? lockdep_hardirqs_on+0x421/0x5e0 [ 91.637306][ T9784] n_tty_receive_buf2+0x34/0x40 [ 91.642198][ T9784] tty_ldisc_receive_buf+0xad/0x1c0 [ 91.647391][ T9784] ? n_tty_receive_buf_common+0x2b70/0x2b70 [ 91.653351][ T9784] paste_selection+0x1ff/0x4d0 [ 91.658094][ T9784] ? sel_pos+0x90/0x90 [ 91.662152][ T9784] ? lock_downgrade+0x920/0x920 [ 91.667020][ T9784] ? wake_up_q+0x140/0x140 [ 91.671451][ T9784] tioclinux+0x133/0x480 [ 91.675685][ T9784] vt_ioctl+0x1a41/0x26c0 [ 91.680000][ T9784] ? complete_change_console+0x3a0/0x3a0 [ 91.685634][ T9784] ? tomoyo_execute_permission+0x4a0/0x4a0 [ 91.691448][ T9784] ? __sanitizer_cov_trace_switch+0x49/0x80 [ 91.697334][ T9784] ? tty_jobctrl_ioctl+0x50/0xd40 [ 91.702368][ T9784] ? complete_change_console+0x3a0/0x3a0 [ 91.711467][ T9784] tty_ioctl+0xa37/0x14f0 [ 91.715806][ T9784] ? tty_vhangup+0x30/0x30 [ 91.720296][ T9784] ? __sanitizer_cov_trace_const_cmp2+0x18/0x20 [ 91.726523][ T9784] ? do_vfs_ioctl+0x568/0x13b0 [ 91.731293][ T9784] ? ioctl_file_clone+0x180/0x180 [ 91.736302][ T9784] ? file_open_root+0x430/0x430 [ 91.741146][ T9784] ? tomoyo_file_ioctl+0x23/0x30 [ 91.746103][ T9784] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 91.752337][ T9784] ? security_file_ioctl+0x8d/0xc0 [ 91.757445][ T9784] ? tty_vhangup+0x30/0x30 [ 91.761844][ T9784] ksys_ioctl+0x123/0x180 [ 91.766151][ T9784] __x64_sys_ioctl+0x73/0xb0 [ 91.770727][ T9784] do_syscall_64+0xfa/0x790 [ 91.775211][ T9784] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 91.781081][ T9784] RIP: 0033:0x440299 [ 91.784965][ T9784] 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 [ 91.804876][ T9784] RSP: 002b:00007ffd9a218758 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 91.813272][ T9784] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440299 [ 91.821233][ T9784] RDX: 0000000020000000 RSI: 000000000000541c RDI: 0000000000000004 [ 91.829191][ T9784] RBP: 00000000006ca018 R08: 00000000004006cc R09: 00000000004002c8 [ 91.837240][ T9784] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401b80 [ 91.845189][ T9784] R13: 0000000000401c10 R14: 0000000000000000 R15: 000000