[ OK ] Started OpenBSD Secure Shell server. [ 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. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.109' (ECDSA) to the list of known hosts. 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 syzkaller login: [ 392.055484] [ 392.057147] ====================================================== [ 392.063453] WARNING: possible circular locking dependency detected [ 392.069760] 4.19.204-syzkaller #0 Not tainted [ 392.074244] ------------------------------------------------------ [ 392.080639] syz-executor210/11499 is trying to acquire lock: [ 392.086576] 000000000a71b458 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 [ 392.093319] [ 392.093319] but task is already holding lock: [ 392.099282] 000000006c872fb1 (sb_writers#3){.+.+}, at: do_sendfile+0x97d/0xc30 [ 392.106652] [ 392.106652] which lock already depends on the new lock. [ 392.106652] [ 392.114961] [ 392.114961] the existing dependency chain (in reverse order) is: [ 392.122569] [ 392.122569] -> #3 (sb_writers#3){.+.+}: [ 392.128223] mnt_want_write+0x3a/0xb0 [ 392.132538] ovl_create_object+0x96/0x290 [ 392.137210] lookup_open+0x893/0x1a20 [ 392.141528] path_openat+0x1094/0x2df0 [ 392.145940] do_filp_open+0x18c/0x3f0 [ 392.150252] do_sys_open+0x3b3/0x520 [ 392.154475] do_syscall_64+0xf9/0x620 [ 392.158788] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 392.164481] [ 392.164481] -> #2 (&ovl_i_mutex_dir_key[depth]){++++}: [ 392.171230] path_openat+0x17ec/0x2df0 [ 392.175627] do_filp_open+0x18c/0x3f0 [ 392.179937] do_open_execat+0x11d/0x5b0 [ 392.184419] __do_execve_file+0x1a8b/0x2360 [ 392.189273] do_execve+0x35/0x50 [ 392.193153] __x64_sys_execve+0x7c/0xa0 [ 392.197627] do_syscall_64+0xf9/0x620 [ 392.201924] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 392.207607] [ 392.207607] -> #1 (&sig->cred_guard_mutex){+.+.}: [ 392.213927] proc_pid_stack+0x160/0x350 [ 392.218413] proc_single_show+0xeb/0x170 [ 392.222976] seq_read+0x4e0/0x11c0 [ 392.227020] do_iter_read+0x471/0x630 [ 392.231329] vfs_readv+0xe5/0x150 [ 392.235284] __x64_sys_preadv+0x22b/0x310 [ 392.239939] do_syscall_64+0xf9/0x620 [ 392.244250] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 392.249934] [ 392.249934] -> #0 (&p->lock){+.+.}: [ 392.255027] __mutex_lock+0xd7/0x1200 [ 392.259337] seq_read+0x6b/0x11c0 [ 392.263315] proc_reg_read+0x1bd/0x2d0 [ 392.267704] do_iter_read+0x471/0x630 [ 392.272007] vfs_readv+0xe5/0x150 [ 392.275969] default_file_splice_read+0x457/0xa00 [ 392.281312] do_splice_to+0x10e/0x160 [ 392.285705] splice_direct_to_actor+0x2b9/0x8d0 [ 392.290880] do_splice_direct+0x1a7/0x270 [ 392.295544] do_sendfile+0x550/0xc30 [ 392.299756] __se_sys_sendfile64+0x147/0x160 [ 392.304667] do_syscall_64+0xf9/0x620 [ 392.308973] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 392.314655] [ 392.314655] other info that might help us debug this: [ 392.314655] [ 392.322774] Chain exists of: [ 392.322774] &p->lock --> &ovl_i_mutex_dir_key[depth] --> sb_writers#3 [ 392.322774] [ 392.333855] Possible unsafe locking scenario: [ 392.333855] [ 392.339887] CPU0 CPU1 [ 392.344527] ---- ---- [ 392.349167] lock(sb_writers#3); [ 392.352598] lock(&ovl_i_mutex_dir_key[depth]); [ 392.359845] lock(sb_writers#3); [ 392.365797] lock(&p->lock); [ 392.368885] [ 392.368885] *** DEADLOCK *** [ 392.368885] [ 392.374928] 1 lock held by syz-executor210/11499: [ 392.379743] #0: 000000006c872fb1 (sb_writers#3){.+.+}, at: do_sendfile+0x97d/0xc30 [ 392.387523] [ 392.387523] stack backtrace: [ 392.391997] CPU: 0 PID: 11499 Comm: syz-executor210 Not tainted 4.19.204-syzkaller #0 [ 392.399939] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 392.409285] Call Trace: [ 392.411856] dump_stack+0x1fc/0x2ef [ 392.415478] print_circular_bug.constprop.0.cold+0x2d7/0x41e [ 392.421259] __lock_acquire+0x30c9/0x3ff0 [ 392.425425] ? __bpf_address_lookup+0x330/0x330 [ 392.430071] ? mark_held_locks+0xf0/0xf0 [ 392.434112] ? is_bpf_text_address+0xfc/0x1b0 [ 392.438598] ? kernel_text_address+0xbd/0xf0 [ 392.442988] lock_acquire+0x170/0x3c0 [ 392.446764] ? seq_read+0x6b/0x11c0 [ 392.450627] ? seq_read+0x6b/0x11c0 [ 392.454253] __mutex_lock+0xd7/0x1200 [ 392.458043] ? seq_read+0x6b/0x11c0 [ 392.461651] ? aa_file_perm+0x417/0xd20 [ 392.465604] ? seq_read+0x6b/0x11c0 [ 392.469213] ? mutex_trylock+0x1a0/0x1a0 [ 392.473265] ? aa_path_link+0x410/0x410 [ 392.477234] ? lock_acquire+0x170/0x3c0 [ 392.481194] ? check_preemption_disabled+0x41/0x280 [ 392.486186] ? seq_hex_dump+0x450/0x450 [ 392.490157] seq_read+0x6b/0x11c0 [ 392.493591] ? fsnotify+0x84e/0xe10 [ 392.497197] ? fsnotify_first_mark+0x200/0x200 [ 392.501757] ? seq_hex_dump+0x450/0x450 [ 392.505709] proc_reg_read+0x1bd/0x2d0 [ 392.509574] ? proc_reg_unlocked_ioctl+0x2c0/0x2c0 [ 392.514481] do_iter_read+0x471/0x630 [ 392.518624] vfs_readv+0xe5/0x150 [ 392.522057] ? compat_rw_copy_check_uvector+0x410/0x410 [ 392.527404] ? push_pipe+0x3fe/0x770 [ 392.531101] ? iov_iter_get_pages_alloc+0x339/0x1150 [ 392.536355] ? iov_iter_bvec+0x130/0x130 [ 392.540407] ? lock_downgrade+0x720/0x720 [ 392.544539] ? iov_iter_pipe+0xb4/0x2c0 [ 392.548491] default_file_splice_read+0x457/0xa00 [ 392.553327] ? alloc_pipe_info+0x193/0x470 [ 392.557546] ? do_splice_direct+0x270/0x270 [ 392.561940] ? do_syscall_64+0xf9/0x620 [ 392.565894] ? aa_path_link+0x410/0x410 [ 392.569847] ? mark_held_locks+0xf0/0xf0 [ 392.573894] ? check_preemption_disabled+0x41/0x280 [ 392.578917] ? security_file_permission+0x1c0/0x220 [ 392.583920] ? do_splice_direct+0x270/0x270 [ 392.588222] do_splice_to+0x10e/0x160 [ 392.592004] splice_direct_to_actor+0x2b9/0x8d0 [ 392.596656] ? generic_pipe_buf_nosteal+0x10/0x10 [ 392.601756] ? do_splice_to+0x160/0x160 [ 392.605796] do_splice_direct+0x1a7/0x270 [ 392.609924] ? splice_direct_to_actor+0x8d0/0x8d0 [ 392.614762] ? rcu_read_lock_sched_held+0x16c/0x1d0 [ 392.619767] do_sendfile+0x550/0xc30 [ 392.623463] ? do_compat_pwritev64+0x1b0/0x1b0 [ 392.628030] ? __se_sys_futex+0x28f/0x3b0 [ 392.632169] ? __se_sys_futex+0x298/0x3b0 [ 392.636308] __se_sys_sendfile64+0x147/0x160 [ 392.640795] ? __se_sys_sendfile+0x180/0x180 [ 392.645182] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 392.650526] ? trace_hardirqs_off_caller+0x6e/0x210 [ 392.655871] ? do_syscall_64+0x21/0x620 [ 392.659849] do_syscall_64+0xf9/0x620 [ 392.663641] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 392.668832] RIP: 0033:0x44e369 [ 392.672000] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 31 18 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 bc ff ff ff f7 d8 64 89 01 48 [ 392.690878] RSP: 002b:00007f5e7fc50178 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 [ 392.698564] RAX: ffffffffffffffda RBX: 00000000004cc4c8 RCX: 000000000044e369 executing program executing program executing program executing program [ 392.705811] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003 [ 392.713150] RBP: 00000000004cc4c0 R08: 0000000000000000 R09: 0000000000000000 [ 392.720409] R10: 4000000000010046 R11: 0000000000000246 R12: 00000000004cc4cc [ 392.727655] R13: 00007ffd453d3eef R14: 00007f5e7fc50300 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 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 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 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