[ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Reached target Login Prompts. [ OK ] Started OpenBSD Secure Shell server. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.35' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 53.724538][ T8416] [ 53.726915][ T8416] ====================================================== [ 53.734023][ T8416] WARNING: possible circular locking dependency detected [ 53.741138][ T8416] 5.13.0-rc7-syzkaller #0 Not tainted [ 53.746672][ T8416] ------------------------------------------------------ [ 53.753709][ T8416] systemd-udevd/8416 is trying to acquire lock: [ 53.760222][ T8416] ffffffff8d671668 (loop_ctl_mutex){+.+.}-{3:3}, at: loop_probe+0xe1/0x220 [ 53.768874][ T8416] [ 53.768874][ T8416] but task is already holding lock: [ 53.776323][ T8416] ffffffff8d4daf88 (major_names_lock){+.+.}-{3:3}, at: blk_request_module+0x2f/0x1c0 [ 53.786019][ T8416] [ 53.786019][ T8416] which lock already depends on the new lock. [ 53.786019][ T8416] [ 53.796534][ T8416] [ 53.796534][ T8416] the existing dependency chain (in reverse order) is: [ 53.805674][ T8416] [ 53.805674][ T8416] -> #3 (major_names_lock){+.+.}-{3:3}: [ 53.813607][ T8416] lock_acquire+0x182/0x4a0 [ 53.818820][ T8416] __mutex_lock_common+0x1bf/0x3100 [ 53.824552][ T8416] mutex_lock_nested+0x1a/0x20 [ 53.829857][ T8416] __register_blkdev+0x2c/0x360 [ 53.835245][ T8416] register_mtd_blktrans+0x94/0x3d0 [ 53.841009][ T8416] do_one_initcall+0x1a7/0x400 [ 53.846301][ T8416] do_initcall_level+0x14a/0x1f5 [ 53.851751][ T8416] do_initcalls+0x4b/0x8c [ 53.856592][ T8416] kernel_init_freeable+0x3fd/0x58a [ 53.863083][ T8416] kernel_init+0xd/0x290 [ 53.868079][ T8416] ret_from_fork+0x1f/0x30 [ 53.873136][ T8416] [ 53.873136][ T8416] -> #2 (mtd_table_mutex){+.+.}-{3:3}: [ 53.880974][ T8416] lock_acquire+0x182/0x4a0 [ 53.886001][ T8416] __mutex_lock_common+0x1bf/0x3100 [ 53.891806][ T8416] mutex_lock_nested+0x1a/0x20 [ 53.897101][ T8416] blktrans_open+0x61/0x430 [ 53.902130][ T8416] __blkdev_get+0x293/0xa50 [ 53.907140][ T8416] blkdev_get_by_dev+0xf9/0x640 [ 53.912535][ T8416] blkdev_open+0x132/0x2c0 [ 53.917788][ T8416] do_dentry_open+0x7cb/0x1010 [ 53.923069][ T8416] path_openat+0x28e6/0x39b0 [ 53.928181][ T8416] do_filp_open+0x221/0x460 [ 53.933197][ T8416] do_sys_openat2+0x124/0x460 [ 53.938392][ T8416] __x64_sys_open+0x221/0x270 [ 53.943694][ T8416] do_syscall_64+0x3f/0xb0 [ 53.948629][ T8416] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 53.955106][ T8416] [ 53.955106][ T8416] -> #1 (&bdev->bd_mutex){+.+.}-{3:3}: [ 53.962744][ T8416] lock_acquire+0x182/0x4a0 [ 53.967781][ T8416] __mutex_lock_common+0x1bf/0x3100 [ 53.973493][ T8416] mutex_lock_nested+0x1a/0x20 [ 53.978786][ T8416] del_gendisk+0x2ab/0x860 [ 53.983721][ T8416] loop_control_ioctl+0x62c/0x770 [ 53.989435][ T8416] __se_sys_ioctl+0xfb/0x170 [ 53.994541][ T8416] do_syscall_64+0x3f/0xb0 [ 54.000079][ T8416] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 54.006532][ T8416] [ 54.006532][ T8416] -> #0 (loop_ctl_mutex){+.+.}-{3:3}: [ 54.014085][ T8416] check_prevs_add+0x4f9/0x5b60 [ 54.019501][ T8416] __lock_acquire+0x4307/0x6040 [ 54.025052][ T8416] lock_acquire+0x182/0x4a0 [ 54.030116][ T8416] __mutex_lock_common+0x1bf/0x3100 [ 54.035850][ T8416] mutex_lock_nested+0x1a/0x20 [ 54.041211][ T8416] loop_probe+0xe1/0x220 [ 54.045984][ T8416] blk_request_module+0x19d/0x1c0 [ 54.051518][ T8416] blkdev_get_no_open+0x44/0x1f0 [ 54.057187][ T8416] blkdev_get_by_dev+0x82/0x640 [ 54.062558][ T8416] blkdev_open+0x132/0x2c0 [ 54.067621][ T8416] do_dentry_open+0x7cb/0x1010 [ 54.072925][ T8416] path_openat+0x28e6/0x39b0 [ 54.078071][ T8416] do_filp_open+0x221/0x460 [ 54.083093][ T8416] do_sys_openat2+0x124/0x460 [ 54.088500][ T8416] __x64_sys_open+0x221/0x270 [ 54.093842][ T8416] do_syscall_64+0x3f/0xb0 [ 54.098953][ T8416] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 54.105492][ T8416] [ 54.105492][ T8416] other info that might help us debug this: [ 54.105492][ T8416] [ 54.115939][ T8416] Chain exists of: [ 54.115939][ T8416] loop_ctl_mutex --> mtd_table_mutex --> major_names_lock [ 54.115939][ T8416] [ 54.129046][ T8416] Possible unsafe locking scenario: [ 54.129046][ T8416] [ 54.136587][ T8416] CPU0 CPU1 [ 54.141962][ T8416] ---- ---- [ 54.147371][ T8416] lock(major_names_lock); [ 54.151898][ T8416] lock(mtd_table_mutex); [ 54.158832][ T8416] lock(major_names_lock); [ 54.165846][ T8416] lock(loop_ctl_mutex); [ 54.170190][ T8416] [ 54.170190][ T8416] *** DEADLOCK *** [ 54.170190][ T8416] [ 54.178349][ T8416] 1 lock held by systemd-udevd/8416: [ 54.183716][ T8416] #0: ffffffff8d4daf88 (major_names_lock){+.+.}-{3:3}, at: blk_request_module+0x2f/0x1c0 [ 54.193704][ T8416] [ 54.193704][ T8416] stack backtrace: [ 54.199586][ T8416] CPU: 0 PID: 8416 Comm: systemd-udevd Not tainted 5.13.0-rc7-syzkaller #0 [ 54.208167][ T8416] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 54.218215][ T8416] Call Trace: [ 54.221490][ T8416] dump_stack+0x202/0x31e [ 54.225816][ T8416] ? show_regs_print_info+0x12/0x12 [ 54.231014][ T8416] ? log_buf_vmcoreinfo_setup+0x498/0x498 [ 54.236730][ T8416] ? save_trace+0x5a/0x9f0 [ 54.241159][ T8416] print_circular_bug+0xb17/0xdc0 [ 54.246195][ T8416] ? hlock_conflict+0x1f0/0x1f0 [ 54.251035][ T8416] ? __bfs+0x369/0x700 [ 54.255119][ T8416] ? check_path+0x40/0x40 [ 54.259482][ T8416] ? noop_count+0x30/0x30 [ 54.263970][ T8416] ? save_trace+0x5a/0x9f0 [ 54.268412][ T8416] check_noncircular+0x2cc/0x390 [ 54.273507][ T8416] ? add_chain_block+0x850/0x850 [ 54.278445][ T8416] ? mark_lock+0x199/0x1eb0 [ 54.282940][ T8416] ? mark_lock+0x199/0x1eb0 [ 54.287427][ T8416] ? __bfs+0x700/0x700 [ 54.291481][ T8416] check_prevs_add+0x4f9/0x5b60 [ 54.296337][ T8416] ? __bfs+0x700/0x700 [ 54.300394][ T8416] ? __bfs+0x700/0x700 [ 54.304448][ T8416] ? reacquire_held_locks+0x5f0/0x5f0 [ 54.309802][ T8416] ? mark_lock+0x199/0x1eb0 [ 54.314294][ T8416] ? __lock_acquire+0x13b0/0x6040 [ 54.319311][ T8416] ? __bfs+0x700/0x700 [ 54.323366][ T8416] ? mark_lock+0x199/0x1eb0 [ 54.327855][ T8416] ? __lock_acquire+0x13b0/0x6040 [ 54.332858][ T8416] ? __lock_acquire+0x13b0/0x6040 [ 54.337876][ T8416] ? __lock_acquire+0x13b0/0x6040 [ 54.342896][ T8416] ? mark_lock+0x199/0x1eb0 [ 54.347394][ T8416] ? mark_lock+0x199/0x1eb0 [ 54.351874][ T8416] ? __bfs+0x700/0x700 [ 54.355922][ T8416] ? __bfs+0x700/0x700 [ 54.359985][ T8416] ? mark_lock+0x199/0x1eb0 [ 54.364470][ T8416] ? __pv_queued_spin_lock_slowpath+0x9a0/0xcb0 [ 54.370694][ T8416] ? __pv_queued_spin_unlock_slowpath+0x2e0/0x2e0 [ 54.377098][ T8416] ? lockdep_lock+0x1bc/0x2c0 [ 54.381860][ T8416] ? lockdep_count_forward_deps+0x240/0x240 [ 54.387742][ T8416] ? rcu_read_lock_sched_held+0x87/0x110 [ 54.393388][ T8416] __lock_acquire+0x4307/0x6040 [ 54.398242][ T8416] ? __bfs+0x700/0x700 [ 54.402390][ T8416] ? trace_lock_acquire+0x180/0x180 [ 54.407603][ T8416] ? stack_trace_save+0x1e0/0x1e0 [ 54.412909][ T8416] ? trace_lock_acquire+0x180/0x180 [ 54.418543][ T8416] ? rcu_read_lock_sched_held+0x87/0x110 [ 54.424172][ T8416] ? __bpf_trace_rcu_stall_warning+0x10/0x10 [ 54.430150][ T8416] lock_acquire+0x182/0x4a0 [ 54.434649][ T8416] ? loop_probe+0xe1/0x220 [ 54.439055][ T8416] ? read_lock_is_recursive+0x10/0x10 [ 54.444423][ T8416] ? __might_sleep+0x100/0x100 [ 54.449177][ T8416] __mutex_lock_common+0x1bf/0x3100 [ 54.454363][ T8416] ? loop_probe+0xe1/0x220 [ 54.458765][ T8416] ? ilookup+0x9b/0x220 [ 54.462906][ T8416] ? loop_probe+0xe1/0x220 [ 54.467317][ T8416] ? rcu_read_lock_sched_held+0x87/0x110 [ 54.472952][ T8416] ? mutex_lock_io_nested+0x60/0x60 [ 54.478146][ T8416] ? __mutex_lock_common+0x568/0x3100 [ 54.483537][ T8416] ? blk_request_module+0x2f/0x1c0 [ 54.488643][ T8416] ? mutex_lock_io_nested+0x60/0x60 [ 54.493848][ T8416] mutex_lock_nested+0x1a/0x20 [ 54.498600][ T8416] loop_probe+0xe1/0x220 [ 54.502830][ T8416] ? loop_info64_to_compat+0x5b0/0x5b0 [ 54.508274][ T8416] ? do_raw_spin_unlock+0x134/0x8a0 [ 54.513467][ T8416] ? loop_info64_to_compat+0x5b0/0x5b0 [ 54.518924][ T8416] blk_request_module+0x19d/0x1c0 [ 54.523954][ T8416] blkdev_get_no_open+0x44/0x1f0 [ 54.528879][ T8416] blkdev_get_by_dev+0x82/0x640 [ 54.533717][ T8416] blkdev_open+0x132/0x2c0 [ 54.538119][ T8416] ? block_ioctl+0xf0/0xf0 [ 54.542516][ T8416] do_dentry_open+0x7cb/0x1010 [ 54.547392][ T8416] path_openat+0x28e6/0x39b0 [ 54.551976][ T8416] ? stack_trace_snprint+0xe0/0xe0 [ 54.557079][ T8416] ? do_filp_open+0x460/0x460 [ 54.561765][ T8416] ? alloc_fd+0x5eb/0x690 [ 54.566096][ T8416] ? rcu_read_lock_sched_held+0x87/0x110 [ 54.571716][ T8416] ? __bpf_trace_rcu_stall_warning+0x10/0x10 [ 54.577717][ T8416] do_filp_open+0x221/0x460 [ 54.582210][ T8416] ? vfs_tmpfile+0x230/0x230 [ 54.586803][ T8416] ? alloc_fd+0x5eb/0x690 [ 54.591214][ T8416] ? do_raw_spin_unlock+0x134/0x8a0 [ 54.596414][ T8416] ? _raw_spin_unlock+0x24/0x40 [ 54.601279][ T8416] ? alloc_fd+0x5eb/0x690 [ 54.605608][ T8416] do_sys_openat2+0x124/0x460 [ 54.610295][ T8416] ? __context_tracking_exit+0x7a/0xd0 [ 54.615759][ T8416] ? do_sys_open+0x220/0x220 [ 54.620356][ T8416] ? __context_tracking_enter+0xa5/0xf0 [ 54.625899][ T8416] __x64_sys_open+0x221/0x270 [ 54.630582][ T8416] ? do_sys_openat2+0x460/0x460 [ 54.635423][ T8416] ? vtime_user_enter+0x1ea/0x2d0 [ 54.640470][ T8416] ? __secure_computing+0x19b/0x320 [ 54.645665][ T8416] ? syscall_enter_from_user_mode+0xf0/0x1c0 [ 54.651641][ T8416] do_syscall_64+0x3f/0xb0 [ 54.656150][ T8416] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 54.662048][ T8416] RIP: 0033:0x7f5123fa2840 [ 54.666467][ T8416] Code: 73 01 c3 48 8b 0d 68 77 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 bb 20 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 1e f6 ff ff 48 89 04 24 [ 54.686691][ T8416] RSP: 002b:00007ffd1b1bda38 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 54.695299][ T8416] RAX: ffffffffffffffda RBX: 0000558c34d448f0 RCX: 00007f5123fa2840 [ 54.703379][ T8416] RDX: 0000558c33095fe3 RSI: 00000000000a0800 RDI: 0000558c34d44830 [ 54.711367][ T8416] RBP: 00007ffd1b1bdbb0 R08: 0000558c33095670 R09: 0000000000000010 [ 54.720208][ T8416] R10: 0000558c33095d0c R11: 0000000000000246 R12: 00007ffd1b1bdb00 [ 54.728925][ T8416] R13: 0000558c34d46010 R14: 0000000000000003 R15: 000000000000000e executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program