Buffer I/O error on dev loop0, logical block 6, lost async page write Buffer I/O error on dev loop0, logical block 7, lost async page write Buffer I/O error on dev loop0, logical block 8, lost async page write Buffer I/O error on dev loop0, logical block 9, lost async page write kworker/dying (29) used greatest stack depth: 8440 bytes left INFO: task syz-executor4:17435 blocked for more than 120 seconds. Not tainted 4.16.0+ #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D22136 17435 4528 0x00000004 Call Trace: context_switch kernel/sched/core.c:2848 [inline] __schedule+0x807/0x1e40 kernel/sched/core.c:3490 schedule+0xef/0x430 kernel/sched/core.c:3549 io_schedule+0x1c/0x70 kernel/sched/core.c:5169 wait_on_page_bit_common+0x4dc/0x770 mm/filemap.c:1099 wait_on_page_bit mm/filemap.c:1132 [inline] wait_on_page_writeback include/linux/pagemap.h:546 [inline] __filemap_fdatawait_range+0x31e/0x4c0 mm/filemap.c:533 file_fdatawait_range+0x47/0x60 mm/filemap.c:581 ksys_sync_file_range+0x230/0x300 fs/sync.c:355 SYSC_sync_file_range fs/sync.c:366 [inline] SyS_sync_file_range+0x2c/0x40 fs/sync.c:363 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x455259 RSP: 002b:00007f28fbd73c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000115 RAX: ffffffffffffffda RBX: 00007f28fbd746d4 RCX: 0000000000455259 RDX: 000000007fffffff RSI: 0000000000000002 RDI: 0000000000000014 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000007 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000651 R14: 00000000006fc838 R15: 0000000000000000 Showing all locks held in the system: 3 locks held by kworker/u4:0/6: #0: 00000000874eb613 ((wq_completion)"writeback"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 00000000874eb613 ((wq_completion)"writeback"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000874eb613 ((wq_completion)"writeback"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000874eb613 ((wq_completion)"writeback"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 00000000874eb613 ((wq_completion)"writeback"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000874eb613 ((wq_completion)"writeback"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000874eb613 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 #1: 00000000329f8197 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 #2: 000000002fd50b8d (&type->s_umount_key#35){.+.+}, at: trylock_super+0x22/0x110 fs/super.c:395 2 locks held by khungtaskd/882: #0: 000000005d555efa (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 000000005d555efa (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 00000000958c8746 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4360: #0: 00000000b3971b41 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 fs/file.c:766 2 locks held by getty/4451: #0: 000000004e31d0fe (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000044569ceb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4452: #0: 000000001d7ea5a0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000df80c8d5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4453: #0: 00000000a1ccdbd1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000e2d5473f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4454: #0: 00000000769e1a78 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000b8f8da58 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4455: #0: 00000000c112775a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000003e0b2dcb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4456: #0: 00000000d2427d17 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000ad5494a5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/17102: #0: 0000000020e2631a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000ce700193 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 1 lock held by syz-executor2/17479: #0: 000000004cc28ddf (&bdev->bd_mutex){+.+.}, at: iterate_bdevs+0xce/0x291 fs/block_dev.c:2160 1 lock held by syz-executor2/17518: #0: 000000004cc28ddf (&bdev->bd_mutex){+.+.}, at: iterate_bdevs+0xce/0x291 fs/block_dev.c:2160 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 882 Comm: khungtaskd Not tainted 4.16.0+ #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0xc10/0xf60 kernel/hung_task.c:249 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4358 Comm: rs:main Q:Reg Not tainted 4.16.0+ #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:update_stack_state+0x65/0x670 arch/x86/kernel/unwind_frame.c:208 RSP: 0018:ffff8801b119e238 EFLAGS: 00000282 RAX: ffffed0036233c4f RBX: ffff8801b119e468 RCX: ffff8801b119e418 RDX: dffffc0000000000 RSI: ffff8801b119e768 RDI: ffff8801b119e468 RBP: ffff8801b119e340 R08: ffff8801b119e4a0 R09: ffff8801b12ea040 R10: ffffed0036233c97 R11: ffff8801b119e4bf R12: 1ffff10036233c4f R13: ffff8801b119e768 R14: ffff8801b119e468 R15: ffff8801b119e4b8 FS: 00007fe93ae19700(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000023af000 CR3: 00000001b11fa000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: unwind_next_frame.part.7+0x1a9/0x9c0 arch/x86/kernel/unwind_frame.c:329 unwind_next_frame+0x3e/0x50 arch/x86/kernel/unwind_frame.c:287 __save_stack_trace+0x6e/0xd0 arch/x86/kernel/stacktrace.c:44 save_stack_trace+0x1a/0x20 arch/x86/kernel/stacktrace.c:60 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:552 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3542 ext4_es_alloc_extent fs/ext4/extents_status.c:334 [inline] __es_insert_extent+0x2fd/0x1130 fs/ext4/extents_status.c:673 ext4_es_insert_extent+0x2d9/0x7c0 fs/ext4/extents_status.c:727 ext4_ext_put_gap_in_cache+0x150/0x1d0 fs/ext4/extents.c:2357 ext4_ext_map_blocks+0x242b/0x6300 fs/ext4/extents.c:4363 ext4_da_map_blocks fs/ext4/inode.c:1853 [inline] ext4_da_get_block_prep+0x10a0/0x1b50 fs/ext4/inode.c:1944 ext4_block_write_begin+0x5da/0x1560 fs/ext4/inode.c:1193 ext4_da_write_begin+0x408/0x1260 fs/ext4/inode.c:3065 generic_perform_write+0x39a/0x6a0 mm/filemap.c:3138 __generic_file_write_iter+0x3be/0x5e0 mm/filemap.c:3263 ext4_file_write_iter+0x6dc/0x12e0 fs/ext4/file.c:266 call_write_iter include/linux/fs.h:1782 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x5bc/0x880 fs/read_write.c:487 vfs_write+0x1f8/0x560 fs/read_write.c:549 ksys_write+0xf9/0x250 fs/read_write.c:598 SYSC_write fs/read_write.c:610 [inline] SyS_write+0x24/0x30 fs/read_write.c:607 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7fe93c87719d RSP: 002b:00007fe93ae17eb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000017a RCX: 00007fe93c87719d RDX: 000000000000017a RSI: 00000000023a0a90 RDI: 0000000000000005 RBP: 00000000023a0a90 R08: 34393278302f3962 R09: 5d3534323734302e R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007fe93ae18330 R14: 0000000000000004 R15: 00000000023a0890 Code: 38 ff ff ff b3 8a b5 41 48 c7 85 40 ff ff ff d1 d1 76 88 48 c7 85 48 ff ff ff a0 ca 33 81 4c 89 a5 18 ff ff ff c7 00 f1 f1 f1 f1 40 04 00 f2 f2 f2 c7 40 08 f2 f2 f2 f2 c7 40 0c 00 f2 f2 f2 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.221 msecs