INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added 'ci-upstream-kasan-gce-4,10.128.0.50' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 42.134311] [ 42.135960] ====================================================== [ 42.142239] WARNING: possible circular locking dependency detected [ 42.148522] 4.13.0+ #81 Not tainted [ 42.152111] ------------------------------------------------------ [ 42.158390] loop0/2986 is trying to acquire lock: [ 42.163193] (&sb->s_type->i_mutex_key#9){++++}, at: [] generic_file_write_iter+0xdc/0x7a0 [ 42.173132] [ 42.173132] but now in release context of a crosslock acquired at the following: [ 42.182102] ((complete)&ret.event){+.+.}, at: [] submit_bio_wait+0x15e/0x200 [ 42.190907] [ 42.190907] which lock already depends on the new lock. [ 42.190907] [ 42.199186] [ 42.199186] the existing dependency chain (in reverse order) is: [ 42.206770] [ 42.206770] -> #4 ((complete)&ret.event){+.+.}: [ 42.212889] __lock_acquire+0x328f/0x4620 [ 42.217523] lock_acquire+0x1d5/0x580 [ 42.221810] wait_for_completion_io+0xc8/0x770 [ 42.226877] submit_bio_wait+0x15e/0x200 [ 42.231423] blkdev_issue_zeroout+0x13c/0x1d0 [ 42.236405] ext4_init_inode_table+0x4fd/0xdb1 [ 42.241471] ext4_lazyinit_thread+0x81a/0xd40 [ 42.246449] kthread+0x39c/0x470 [ 42.250298] ret_from_fork+0x2a/0x40 [ 42.254494] [ 42.254494] -> #3 (&meta_group_info[i]->alloc_sem){++++}: [ 42.261480] __lock_acquire+0x328f/0x4620 [ 42.266111] lock_acquire+0x1d5/0x580 [ 42.270395] down_read+0x96/0x150 [ 42.274332] __ext4_new_inode+0x26dc/0x4f00 [ 42.279136] ext4_symlink+0x2d9/0xae0 [ 42.283420] vfs_symlink+0x323/0x560 [ 42.287618] SyS_symlink+0x134/0x200 [ 42.291828] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 42.297066] [ 42.297066] -> #2 (jbd2_handle){.+.+}: [ 42.302402] __lock_acquire+0x328f/0x4620 [ 42.307036] lock_acquire+0x1d5/0x580 [ 42.311324] start_this_handle+0x4b8/0x1080 [ 42.316138] jbd2__journal_start+0x389/0x9f0 [ 42.321032] __ext4_journal_start_sb+0x15f/0x550 [ 42.326273] ext4_dirty_inode+0x56/0xa0 [ 42.330745] __mark_inode_dirty+0x912/0x1170 [ 42.335639] generic_update_time+0x1b2/0x270 [ 42.340531] touch_atime+0x26d/0x2f0 [ 42.344727] ext4_file_mmap+0x161/0x1b0 [ 42.349185] mmap_region+0xa99/0x15a0 [ 42.353468] do_mmap+0x6a1/0xd50 [ 42.357324] vm_mmap_pgoff+0x1de/0x280 [ 42.361695] SyS_mmap_pgoff+0x462/0x5f0 [ 42.366156] SyS_mmap+0x16/0x20 [ 42.369921] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 42.375157] [ 42.375157] -> #1 (&mm->mmap_sem){++++}: [ 42.380665] __lock_acquire+0x328f/0x4620 [ 42.385296] lock_acquire+0x1d5/0x580 [ 42.389580] __might_fault+0x13a/0x1d0 [ 42.393956] _copy_to_user+0x2c/0xc0 [ 42.398154] filldir+0x1a7/0x320 [ 42.402003] dcache_readdir+0x12d/0x5e0 [ 42.406460] iterate_dir+0x4b2/0x5d0 [ 42.410658] SyS_getdents+0x225/0x450 [ 42.414941] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 42.420177] [ 42.420177] -> #0 (&sb->s_type->i_mutex_key#9){++++}: [ 42.426812] down_write+0x87/0x120 [ 42.430837] generic_file_write_iter+0xdc/0x7a0 [ 42.435989] do_iter_readv_writev+0x531/0x7f0 [ 42.440968] do_iter_write+0x15a/0x540 [ 42.445338] vfs_iter_write+0x77/0xb0 [ 42.449617] [ 42.449617] other info that might help us debug this: [ 42.449617] [ 42.457728] Chain exists of: [ 42.457728] &sb->s_type->i_mutex_key#9 --> &meta_group_info[i]->alloc_sem --> (complete)&ret.event [ 42.457728] [ 42.471312] Possible unsafe locking scenario by crosslock: [ 42.471312] [ 42.478462] CPU0 CPU1 [ 42.483091] ---- ---- [ 42.487726] lock(&meta_group_info[i]->alloc_sem); [ 42.492703] lock((complete)&ret.event); [ 42.496813] lock(&sb->s_type->i_mutex_key#9); [ 42.503962] unlock((complete)&ret.event); [ 42.510771] [ 42.510771] *** DEADLOCK *** [ 42.510771] [ 42.516798] 1 lock held by loop0/2986: [ 42.520647] #0: (&x->wait#14){..-.}, at: [] complete+0x18/0x80 [ 42.528324] [ 42.528324] stack backtrace: [ 42.532786] CPU: 1 PID: 2986 Comm: loop0 Not tainted 4.13.0+ #81 [ 42.538893] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.548209] Call Trace: [ 42.550769] dump_stack+0x194/0x257 [ 42.554360] ? arch_local_irq_restore+0x53/0x53 [ 42.558996] print_circular_bug+0x503/0x710 [ 42.563282] ? print_circular_bug_entry+0xb0/0xb0 [ 42.568086] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 42.573240] check_prev_add+0x865/0x1520 [ 42.577270] ? graph_lock+0x170/0x170 [ 42.581035] ? check_usage+0xb70/0xb70 [ 42.584889] ? memcpy+0x45/0x50 [ 42.588132] ? iov_iter_advance+0x2a1/0x13f0 [ 42.592507] ? hlock_class+0x140/0x140 [ 42.596360] lock_commit_crosslock+0xe73/0x1d10 [ 42.600992] ? lock_commit_crosslock+0xe73/0x1d10 [ 42.605801] ? check_prev_add+0x1520/0x1520 [ 42.610087] ? lock_acquire+0x1d5/0x580 [ 42.614022] ? complete+0x18/0x80 [ 42.617442] ? __mnt_drop_write_file+0xd/0x70 [ 42.621899] ? lock_release+0xd70/0xd70 [ 42.625836] ? find_held_lock+0x39/0x1d0 [ 42.629870] complete+0x24/0x80 [ 42.633117] submit_bio_wait_endio+0x9c/0xd0 [ 42.637488] ? bio_iov_iter_get_pages+0x4e0/0x4e0 [ 42.642291] bio_endio+0x2f8/0x8d0 [ 42.645795] ? bio_dirty_fn+0x3e0/0x3e0 [ 42.649737] ? rcu_pm_notify+0xc0/0xc0 [ 42.653590] ? bio_advance+0xf8/0x370 [ 42.657356] blk_update_request+0x2a6/0xe20 [ 42.661644] ? blk_account_io_completion+0x410/0x410 [ 42.666714] blk_mq_end_request+0x54/0x120 [ 42.670916] lo_complete_rq+0xbe/0x1f0 [ 42.674766] __blk_mq_complete_request+0x38f/0x6c0 [ 42.679662] blk_mq_complete_request+0x4f/0x60 [ 42.684206] loop_queue_work+0x26b/0x3900 [ 42.688315] ? do_raw_spin_trylock+0x190/0x190 [ 42.692863] ? lo_rw_aio+0x1e70/0x1e70 [ 42.696713] ? _raw_spin_unlock_irq+0x27/0x70 [ 42.701173] ? finish_task_switch+0x1d3/0x740 [ 42.705632] ? finish_task_switch+0x1aa/0x740 [ 42.710089] ? preempt_notifier_dec+0x20/0x20 [ 42.714549] ? check_noncircular+0x20/0x20 [ 42.718746] ? __schedule+0x8f0/0x2070 [ 42.722599] ? do_raw_spin_trylock+0x190/0x190 [ 42.727142] ? lock_release+0xd70/0xd70 [ 42.731080] ? compat_start_thread+0x80/0x80 [ 42.735454] ? find_held_lock+0x39/0x1d0 [ 42.739483] ? finish_task_switch+0x1aa/0x740 [ 42.743943] ? kthread_worker_fn+0x4ad/0x9b0 [ 42.748316] ? do_raw_spin_trylock+0x190/0x190 [ 42.752860] ? check_same_owner+0x320/0x320 [ 42.757147] ? _raw_spin_unlock_irq+0x27/0x70 [ 42.761619] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.766601] kthread_worker_fn+0x340/0x9b0 [ 42.770800] ? kthread_flush_work+0x560/0x560 [ 42.775258] ? lock_downgrade+0x990/0x990 [ 42.779375] ? complete+0x18/0x80 [ 42.782791] ? schedule+0x108/0x440 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 42.786380] ? __schedule+0x2070/0x2070 [ 42.790319] ? _raw_spin_unlock_irqrestore+0x31/0xba [ 42.795388] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.800376] ? trace_hardirqs_on+0xd/0x10 [ 42.804495] loop_kthread_worker_fn+0x51/0x60 [ 42.808957] kthread+0x39c/0x470 [ 42.812285] ? loop_get_status64+0x110/0x110 [ 42.816655] ? kthread_create_on_node+0x100/0x100 [ 42.821462] ret_from_fork+0x2a/0x40 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program