[ 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 '10.128.0.66' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 33.614633] hrtimer: interrupt took 44271 ns executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.752106] syz-executor778 (8155) used greatest stack depth: 22728 bytes left 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 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 [ 38.234718] overlayfs: failed to resolve './file0': -2 executing program [ 38.369049] [ 38.370707] ====================================================== [ 38.377019] WARNING: possible circular locking dependency detected [ 38.383432] 4.19.197-syzkaller #0 Not tainted [ 38.388045] ------------------------------------------------------ [ 38.394365] syz-executor778/8322 is trying to acquire lock: [ 38.400072] 000000008a7d9386 (&p->lock){+.+.}, at: seq_read+0x6b/0x1160 [ 38.406843] [ 38.406843] but task is already holding lock: [ 38.412813] 00000000cad0160a (sb_writers#3){.+.+}, at: do_sendfile+0x97d/0xc30 [ 38.420204] [ 38.420204] which lock already depends on the new lock. [ 38.420204] [ 38.428528] [ 38.428528] the existing dependency chain (in reverse order) is: [ 38.436234] [ 38.436234] -> #3 (sb_writers#3){.+.+}: [ 38.441703] mnt_want_write+0x3a/0xb0 [ 38.446019] ovl_create_object+0x96/0x290 [ 38.450787] lookup_open+0x893/0x1a20 [ 38.455111] path_openat+0x1094/0x2df0 [ 38.459542] do_filp_open+0x18c/0x3f0 [ 38.463899] do_sys_open+0x3b3/0x520 [ 38.468486] do_syscall_64+0xf9/0x620 [ 38.472835] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.478886] [ 38.478886] -> #2 (&ovl_i_mutex_dir_key[depth]){++++}: [ 38.485661] path_openat+0x17ec/0x2df0 [ 38.490159] do_filp_open+0x18c/0x3f0 [ 38.494549] do_open_execat+0x11d/0x5b0 [ 38.499055] __do_execve_file+0x1a8b/0x2360 [ 38.503978] do_execve+0x35/0x50 [ 38.507852] __x64_sys_execve+0x7c/0xa0 [ 38.512342] do_syscall_64+0xf9/0x620 [ 38.516922] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.522792] [ 38.522792] -> #1 (&sig->cred_guard_mutex){+.+.}: [ 38.529109] proc_pid_personality+0x4a/0x170 [ 38.534148] proc_single_show+0xeb/0x170 [ 38.538956] seq_read+0x4be/0x1160 [ 38.543100] __vfs_read+0xf7/0x750 [ 38.547173] vfs_read+0x194/0x3c0 [ 38.551137] ksys_read+0x12b/0x2a0 [ 38.555217] do_syscall_64+0xf9/0x620 [ 38.559528] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.565383] [ 38.565383] -> #0 (&p->lock){+.+.}: [ 38.570489] __mutex_lock+0xd7/0x1200 [ 38.574809] seq_read+0x6b/0x1160 [ 38.578901] proc_reg_read+0x1bd/0x2d0 [ 38.583412] do_iter_read+0x471/0x630 [ 38.587896] vfs_readv+0xe5/0x150 [ 38.591863] default_file_splice_read+0x457/0xa00 [ 38.597216] do_splice_to+0x10e/0x160 [ 38.601535] splice_direct_to_actor+0x2b9/0x8d0 [ 38.606743] do_splice_direct+0x1a7/0x270 [ 38.611506] do_sendfile+0x550/0xc30 [ 38.615746] __se_sys_sendfile64+0x147/0x160 [ 38.620679] do_syscall_64+0xf9/0x620 [ 38.624991] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 38.630681] [ 38.630681] other info that might help us debug this: [ 38.630681] [ 38.639032] Chain exists of: [ 38.639032] &p->lock --> &ovl_i_mutex_dir_key[depth] --> sb_writers#3 [ 38.639032] [ 38.650276] Possible unsafe locking scenario: [ 38.650276] [ 38.656323] CPU0 CPU1 [ 38.660985] ---- ---- [ 38.665736] lock(sb_writers#3); [ 38.669222] lock(&ovl_i_mutex_dir_key[depth]); [ 38.676612] lock(sb_writers#3); [ 38.682570] lock(&p->lock); [ 38.685665] [ 38.685665] *** DEADLOCK *** [ 38.685665] [ 38.691897] 1 lock held by syz-executor778/8322: [ 38.696744] #0: 00000000cad0160a (sb_writers#3){.+.+}, at: do_sendfile+0x97d/0xc30 [ 38.704827] [ 38.704827] stack backtrace: [ 38.709312] CPU: 1 PID: 8322 Comm: syz-executor778 Not tainted 4.19.197-syzkaller #0 [ 38.717178] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 38.726740] Call Trace: [ 38.729322] dump_stack+0x1fc/0x2ef [ 38.732961] print_circular_bug.constprop.0.cold+0x2d7/0x41e [ 38.738754] __lock_acquire+0x30c9/0x3ff0 [ 38.743011] ? __bpf_address_lookup+0x330/0x330 [ 38.747669] ? mark_held_locks+0xf0/0xf0 [ 38.751735] ? is_bpf_text_address+0xfc/0x1b0 [ 38.756322] ? kernel_text_address+0xbd/0xf0 [ 38.760738] lock_acquire+0x170/0x3c0 [ 38.764548] ? seq_read+0x6b/0x1160 [ 38.768266] ? seq_read+0x6b/0x1160 [ 38.771876] __mutex_lock+0xd7/0x1200 [ 38.775819] ? seq_read+0x6b/0x1160 [ 38.779573] ? aa_file_perm+0x417/0xd20 [ 38.783657] ? seq_read+0x6b/0x1160 [ 38.787321] ? mutex_trylock+0x1a0/0x1a0 [ 38.791413] ? rcu_nmi_exit+0xb3/0x180 [ 38.795333] ? aa_path_link+0x410/0x410 [ 38.799325] ? retint_kernel+0x2d/0x2d [ 38.803243] ? check_preemption_disabled+0x41/0x280 [ 38.808532] ? traverse.part.0+0x590/0x590 [ 38.812813] seq_read+0x6b/0x1160 [ 38.816254] ? fsnotify+0x84e/0xe10 [ 38.819879] ? fsnotify_first_mark+0x200/0x200 [ 38.824662] ? traverse.part.0+0x590/0x590 [ 38.828991] proc_reg_read+0x1bd/0x2d0 [ 38.832973] ? proc_reg_unlocked_ioctl+0x2c0/0x2c0 [ 38.837902] do_iter_read+0x471/0x630 [ 38.841817] vfs_readv+0xe5/0x150 [ 38.845270] ? compat_rw_copy_check_uvector+0x410/0x410 [ 38.850671] ? mark_held_locks+0xa6/0xf0 [ 38.854746] ? push_pipe+0x3fe/0x770 [ 38.858465] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 38.863045] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 38.867878] ? rcu_nmi_exit+0xb3/0x180 [ 38.871851] ? retint_kernel+0x2d/0x2d [ 38.875722] ? default_file_splice_read+0x389/0xa00 [ 38.880809] default_file_splice_read+0x457/0xa00 [ 38.885636] ? alloc_pipe_info+0x193/0x470 [ 38.889855] ? do_splice_direct+0x270/0x270 [ 38.894159] ? do_syscall_64+0xf9/0x620 [ 38.898221] ? aa_path_link+0x410/0x410 [ 38.902294] ? mark_held_locks+0xa6/0xf0 [ 38.906341] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 38.911093] ? mark_held_locks+0xa6/0xf0 [ 38.915153] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 38.919982] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 38.924765] ? security_file_permission+0x1c0/0x220 [ 38.929771] ? do_splice_direct+0x270/0x270 [ 38.934097] do_splice_to+0x10e/0x160 [ 38.937899] splice_direct_to_actor+0x2b9/0x8d0 [ 38.942569] ? generic_pipe_buf_nosteal+0x10/0x10 [ 38.947526] ? do_splice_to+0x160/0x160 [ 38.951505] do_splice_direct+0x1a7/0x270 [ 38.955681] ? splice_direct_to_actor+0x8d0/0x8d0 [ 38.960681] ? rcu_read_lock_sched_held+0x16c/0x1d0 [ 38.965860] do_sendfile+0x550/0xc30 [ 38.969757] ? do_compat_pwritev64+0x1b0/0x1b0 [ 38.974484] ? __se_sys_futex+0x28f/0x3b0 [ 38.978632] ? __se_sys_futex+0x298/0x3b0 [ 38.982790] __se_sys_sendfile64+0x147/0x160 [ 38.987192] ? __se_sys_sendfile+0x180/0x180 [ 38.991772] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 38.997449] ? trace_hardirqs_off_caller+0x6e/0x210 [ 39.002548] ? do_syscall_64+0x21/0x620 [ 39.006730] do_syscall_64+0xf9/0x620 [ 39.010550] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 39.015827] RIP: 0033:0x446339 [ 39.019024] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 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 [ 39.037946] RSP: 002b:00007f96675ec278 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 [ 39.045738] RAX: ffffffffffffffda RBX: 00000000004cb4e0 RCX: 0000000000446339 [ 39.053266] RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004 [ 39.060580] RBP: 000000000049b0a8 R08: 0000000000000000 R09: 0000000000000000 executing program executing program [ 39.067838] R10: 4000000000010046 R11: 0000000000000246 R12: 0030656c69662f2e [ 39.075269] R13: 00007ffece5b9c6f R14: 6c616e6f73726570 R15: 00000000004cb4e8 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 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 44.111534] overlayfs: failed to resolve './file0': -2 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 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