[ 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 '10.128.0.213' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 50.490377][ T8431] [ 50.492777][ T8431] ====================================================== [ 50.499819][ T8431] WARNING: possible circular locking dependency detected [ 50.501210][ T8432] overlayfs: upperdir is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection. [ 50.506824][ T8431] 5.14.0-rc1-syzkaller #0 Not tainted [ 50.506833][ T8431] ------------------------------------------------------ [ 50.506838][ T8431] syz-executor190/8431 is trying to acquire lock: [ 50.506846][ T8431] ffff88801e3633e0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x75a/0x1ba0 [ 50.549196][ T8431] [ 50.549196][ T8431] but task is already holding lock: [ 50.556536][ T8431] ffff8881488a8460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 [ 50.565209][ T8431] [ 50.565209][ T8431] which lock already depends on the new lock. [ 50.565209][ T8431] [ 50.575582][ T8431] [ 50.575582][ T8431] the existing dependency chain (in reverse order) is: [ 50.584565][ T8431] [ 50.584565][ T8431] -> #1 (sb_writers#5){.+.+}-{0:0}: [ 50.591921][ T8431] lock_acquire+0x182/0x4a0 [ 50.596985][ T8431] sb_start_write+0x4f/0x1a0 [ 50.602073][ T8431] mnt_want_write+0x3b/0x80 [ 50.607071][ T8431] ovl_maybe_copy_up+0x117/0x180 [ 50.612504][ T8431] ovl_open+0xa2/0x200 [ 50.617072][ T8431] do_dentry_open+0x7cb/0x1020 [ 50.622335][ T8431] dentry_open+0xc6/0x120 [ 50.627158][ T8431] ima_calc_file_hash+0x157/0x1b00 [ 50.632770][ T8431] ima_collect_measurement+0x283/0x520 [ 50.638724][ T8431] process_measurement+0xf79/0x1ba0 [ 50.644415][ T8431] ima_file_check+0xdb/0x130 [ 50.649498][ T8431] path_openat+0x284a/0x36b0 [ 50.654645][ T8431] do_filp_open+0x253/0x4d0 [ 50.659686][ T8431] do_sys_openat2+0x124/0x460 [ 50.664855][ T8431] __x64_sys_open+0x221/0x270 [ 50.670021][ T8431] do_syscall_64+0x3d/0xb0 [ 50.674936][ T8431] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 50.681322][ T8431] [ 50.681322][ T8431] -> #0 (&iint->mutex){+.+.}-{3:3}: [ 50.688670][ T8431] check_prevs_add+0x4f9/0x5b30 [ 50.694015][ T8431] __lock_acquire+0x4476/0x6100 [ 50.699358][ T8431] lock_acquire+0x182/0x4a0 [ 50.704353][ T8431] __mutex_lock_common+0x1ad/0x3770 [ 50.710044][ T8431] mutex_lock_nested+0x1a/0x20 [ 50.715302][ T8431] process_measurement+0x75a/0x1ba0 [ 50.720994][ T8431] ima_file_check+0xdb/0x130 [ 50.726076][ T8431] path_openat+0x284a/0x36b0 [ 50.731156][ T8431] do_filp_open+0x253/0x4d0 [ 50.736152][ T8431] do_sys_openat2+0x124/0x460 [ 50.741320][ T8431] __x64_sys_openat+0x243/0x290 [ 50.746659][ T8431] do_syscall_64+0x3d/0xb0 [ 50.751568][ T8431] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 50.757951][ T8431] [ 50.757951][ T8431] other info that might help us debug this: [ 50.757951][ T8431] [ 50.768168][ T8431] Possible unsafe locking scenario: [ 50.768168][ T8431] [ 50.775585][ T8431] CPU0 CPU1 [ 50.780925][ T8431] ---- ---- [ 50.786262][ T8431] lock(sb_writers#5); [ 50.790423][ T8431] lock(&iint->mutex); [ 50.797072][ T8431] lock(sb_writers#5); [ 50.803719][ T8431] lock(&iint->mutex); [ 50.807844][ T8431] [ 50.807844][ T8431] *** DEADLOCK *** [ 50.807844][ T8431] [ 50.815959][ T8431] 1 lock held by syz-executor190/8431: [ 50.821384][ T8431] #0: ffff8881488a8460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 [ 50.830514][ T8431] [ 50.830514][ T8431] stack backtrace: [ 50.836373][ T8431] CPU: 0 PID: 8431 Comm: syz-executor190 Not tainted 5.14.0-rc1-syzkaller #0 [ 50.845102][ T8431] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 50.855130][ T8431] Call Trace: [ 50.858388][ T8431] dump_stack_lvl+0x1ae/0x29f [ 50.863050][ T8431] ? show_regs_print_info+0x12/0x12 [ 50.868218][ T8431] ? log_buf_vmcoreinfo_setup+0x498/0x498 [ 50.873918][ T8431] ? save_trace+0x5a/0x9f0 [ 50.878306][ T8431] print_circular_bug+0xb17/0xdc0 [ 50.883333][ T8431] ? hlock_conflict+0x1f0/0x1f0 [ 50.888258][ T8431] ? __bfs+0x369/0x700 [ 50.892300][ T8431] ? check_path+0x40/0x40 [ 50.896603][ T8431] ? noop_count+0x30/0x30 [ 50.900903][ T8431] ? save_trace+0x5a/0x9f0 [ 50.905391][ T8431] check_noncircular+0x2cc/0x390 [ 50.910301][ T8431] ? add_chain_block+0x850/0x850 [ 50.915210][ T8431] ? __bfs+0x369/0x700 [ 50.919254][ T8431] ? noop_count+0x30/0x30 [ 50.923555][ T8431] ? add_chain_block+0x850/0x850 [ 50.928464][ T8431] check_prevs_add+0x4f9/0x5b30 [ 50.933311][ T8431] ? reacquire_held_locks+0x5f0/0x5f0 [ 50.938656][ T8431] ? check_prevs_add+0x1c41/0x5b30 [ 50.943743][ T8431] ? lockdep_lock+0x102/0x2c0 [ 50.948423][ T8431] ? reacquire_held_locks+0x5f0/0x5f0 [ 50.953793][ T8431] ? lockdep_unlock+0x145/0x2e0 [ 50.958642][ T8431] ? check_prevs_add+0x1c41/0x5b30 [ 50.963828][ T8431] ? mark_lock+0x199/0x1eb0 [ 50.968323][ T8431] ? __bfs+0x700/0x700 [ 50.972371][ T8431] ? mark_lock+0x199/0x1eb0 [ 50.976850][ T8431] ? mark_lock+0x199/0x1eb0 [ 50.981336][ T8431] ? __bfs+0x700/0x700 [ 50.985468][ T8431] ? __bfs+0x700/0x700 [ 50.989514][ T8431] ? mark_lock+0x199/0x1eb0 [ 50.993991][ T8431] ? __pv_queued_spin_lock_slowpath+0x9a0/0xcb0 [ 51.000215][ T8431] ? __pv_queued_spin_unlock_slowpath+0x2e0/0x2e0 [ 51.006602][ T8431] ? mark_lock+0x199/0x1eb0 [ 51.011077][ T8431] ? __lock_acquire+0x1385/0x6100 [ 51.016076][ T8431] ? lockdep_lock+0x1bc/0x2c0 [ 51.020724][ T8431] ? lockdep_count_forward_deps+0x240/0x240 [ 51.026590][ T8431] ? __lock_acquire+0x1385/0x6100 [ 51.031591][ T8431] __lock_acquire+0x4476/0x6100 [ 51.036415][ T8431] ? trace_lock_acquire+0x190/0x190 [ 51.041591][ T8431] ? lockdep_lock+0x102/0x2c0 [ 51.046254][ T8431] ? trace_lock_acquire+0x190/0x190 [ 51.051423][ T8431] ? __lock_acquire+0x145b/0x6100 [ 51.056421][ T8431] ? __lock_acquire+0x44fa/0x6100 [ 51.061425][ T8431] ? rcu_read_lock_sched_held+0x87/0x110 [ 51.067031][ T8431] ? __bpf_trace_rcu_stall_warning+0x10/0x10 [ 51.072982][ T8431] ? rcu_read_lock_sched_held+0x87/0x110 [ 51.078590][ T8431] ? __bpf_trace_rcu_stall_warning+0x10/0x10 [ 51.084543][ T8431] ? rcu_lock_release+0x5/0x20 [ 51.089279][ T8431] lock_acquire+0x182/0x4a0 [ 51.093751][ T8431] ? process_measurement+0x75a/0x1ba0 [ 51.099095][ T8431] ? read_lock_is_recursive+0x10/0x10 [ 51.104443][ T8431] ? __might_sleep+0x100/0x100 [ 51.109183][ T8431] __mutex_lock_common+0x1ad/0x3770 [ 51.114353][ T8431] ? process_measurement+0x75a/0x1ba0 [ 51.119694][ T8431] ? __lock_acquire+0x6100/0x6100 [ 51.124692][ T8431] ? integrity_inode_get+0x296/0x300 [ 51.129952][ T8431] ? __lock_acquire+0x6100/0x6100 [ 51.135062][ T8431] ? process_measurement+0x75a/0x1ba0 [ 51.140409][ T8431] ? mutex_lock_io_nested+0x60/0x60 [ 51.145590][ T8431] ? up_write+0x12c/0x4d0 [ 51.149895][ T8431] ? __up_read+0x790/0x790 [ 51.154283][ T8431] ? integrity_inode_get+0x296/0x300 [ 51.159540][ T8431] mutex_lock_nested+0x1a/0x20 [ 51.164277][ T8431] process_measurement+0x75a/0x1ba0 [ 51.169449][ T8431] ? ima_file_mmap+0x150/0x150 [ 51.174191][ T8431] ? rcu_lock_release+0x5/0x20 [ 51.178923][ T8431] ? __lock_acquire+0x6100/0x6100 [ 51.183922][ T8431] ? ext4_file_open+0x2d2/0x8e0 [ 51.188764][ T8431] ? smk_of_task_struct_subj+0x193/0x1d0 [ 51.194368][ T8431] ? smack_task_getsecid_subj+0x22/0x80 [ 51.199887][ T8431] ima_file_check+0xdb/0x130 [ 51.204451][ T8431] ? ima_bprm_check+0x270/0x270 [ 51.209276][ T8431] path_openat+0x284a/0x36b0 [ 51.213841][ T8431] ? do_filp_open+0x4d0/0x4d0 [ 51.218488][ T8431] ? alloc_fd+0x5e1/0x680 [ 51.222801][ T8431] ? rcu_read_lock_sched_held+0x87/0x110 [ 51.228406][ T8431] ? __bpf_trace_rcu_stall_warning+0x10/0x10 [ 51.234372][ T8431] do_filp_open+0x253/0x4d0 [ 51.238850][ T8431] ? vfs_tmpfile+0x230/0x230 [ 51.243411][ T8431] ? alloc_fd+0x5e1/0x680 [ 51.247713][ T8431] ? do_raw_spin_unlock+0x134/0x8a0 [ 51.252885][ T8431] ? _raw_spin_unlock+0x24/0x40 [ 51.257707][ T8431] ? alloc_fd+0x5e1/0x680 [ 51.262008][ T8431] do_sys_openat2+0x124/0x460 [ 51.266659][ T8431] ? __context_tracking_exit+0x7a/0xd0 [ 51.272091][ T8431] ? do_sys_open+0x220/0x220 [ 51.276655][ T8431] __x64_sys_openat+0x243/0x290 [ 51.281478][ T8431] ? __ia32_sys_open+0x270/0x270 [ 51.286388][ T8431] ? syscall_enter_from_user_mode+0x2e/0x1b0 [ 51.292339][ T8431] ? lockdep_hardirqs_on+0x8d/0x130 [ 51.297511][ T8431] ? syscall_enter_from_user_mode+0x2e/0x1b0 [ 51.303472][ T8431] do_syscall_64+0x3d/0xb0 [ 51.307859][ T8431] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 51.313737][ T8431] RIP: 0033:0x444d09 [ 51.317606][ T8431] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 14 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 [ 51.337183][ T8431] RSP: 002b:00007f2680c352f8 EFLAGS: 00000246 ORIG_RAX: 0000