INFO: task hung in do_page_mkwriteINFO: task syz-fuzzer:4845 blocked for more than 140 seconds. Not tainted 4.19.0-rc2-next-20180905+ #57 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-fuzzer D23032 4845 4843 0x00000000 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x87c/0x1df0 kernel/sched/core.c:3473 schedule+0xfb/0x450 kernel/sched/core.c:3517 io_schedule+0x1c/0x70 kernel/sched/core.c:5140 wait_on_page_bit_common mm/filemap.c:1100 [inline] __lock_page+0x5b7/0x7a0 mm/filemap.c:1273 lock_page include/linux/pagemap.h:483 [inline] do_page_mkwrite+0x429/0x520 mm/memory.c:2391 do_shared_fault mm/memory.c:3717 [inline] do_fault mm/memory.c:3756 [inline] handle_pte_fault mm/memory.c:3983 [inline] __handle_mm_fault+0x2a0a/0x4350 mm/memory.c:4107 handle_mm_fault+0x53e/0xc80 mm/memory.c:4144 __do_page_fault+0x620/0xe50 arch/x86/mm/fault.c:1395 do_page_fault+0xf6/0x7a4 arch/x86/mm/fault.c:1470 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1164 RIP: 0033:0x70b581 Code: Bad RIP value. RSP: 002b:000000c4200313f0 EFLAGS: 00010212 RAX: 000000c420031508 RBX: 000000c420031510 RCX: 00007fab12542000 RDX: 0000000000000543 RSI: 000000000072a460 RDI: 000000c420031348 RBP: 000000c420031400 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000949c4a R11: 0000000000000004 R12: 0000000000000000 R13: 0000000000000020 R14: 0000000000000013 R15: 000000000000000f Showing all locks held in the system: 4 locks held by kworker/u4:2/54: #0: 00000000f25e7e8b ((wq_completion)"writeback"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 00000000f25e7e8b ((wq_completion)"writeback"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000f25e7e8b ((wq_completion)"writeback"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000f25e7e8b ((wq_completion)"writeback"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000f25e7e8b ((wq_completion)"writeback"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000f25e7e8b ((wq_completion)"writeback"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000f25e7e8b ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xb44/0x1aa0 kernel/workqueue.c:2124 #1: 000000000158cc5b ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xb9b/0x1aa0 kernel/workqueue.c:2128 #2: 0000000003de3a73 (&fc->fs_type->s_umount_key#29){++++}, at: trylock_super+0x22/0x110 fs/super.c:411 #3: 00000000e6223caa (&sbi->s_journal_flag_rwsem){.+.+}, at: do_writepages+0x9a/0x1a0 mm/page-writeback.c:2340 1 lock held by khungtaskd/782: #0: 00000000fa9407f0 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4436 1 lock held by khugepaged/800: #0: 00000000b66ee8bc (&mm->mmap_sem){++++}, at: collapse_huge_page+0x2bf/0x2250 mm/khugepaged.c:1007 1 lock held by rsyslogd/4733: 2 locks held by getty/4823: #0: 000000000c541463 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000082395d25 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4824: #0: 000000004f74da20 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000039008b68 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4825: #0: 00000000e9d46a5b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000007c111a12 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4826: #0: 00000000222e700d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000063dbb69b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4827: #0: 0000000013a39dde (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000154d8e06 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4828: #0: 00000000210452f2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000006f10cd20 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4829: #0: 00000000ce2bd35d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a6fd9e02 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 1 lock held by syz-fuzzer/4845: #0: 00000000b66ee8bc (&mm->mmap_sem){++++}, at: __do_page_fault+0x389/0xe50 arch/x86/mm/fault.c:1324 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 782 Comm: khungtaskd Not tainted 4.19.0-rc2-next-20180905+ #57 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+0x1c9/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x48/0x88 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b6/0x1cd 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0xb39/0x1040 kernel/hung_task.c:265 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.058 msecs CPU: 0 PID: 4859 Comm: syz-fuzzer Not tainted 4.19.0-rc2-next-20180905+ #57 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:find_held_lock+0x16b/0x1c0 kernel/locking/lockdep.c:3538 Code: 74 89 49 89 dc 48 b8 00 00 00 00 00 fc ff df 48 8b 55 d0 48 c1 ea 03 0f b6 04 02 84 c0 74 04 3c 03 7e 28 48 8b 45 d0 44 89 38 <48> 83 c4 10 4c 89 e0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 45 31 e4 eb RSP: 0018:ffff8801bd147020 EFLAGS: 00000002 RAX: ffff8801bd1470b0 RBX: 1ffff10037a28e12 RCX: ffff8801bd1470b0 RDX: 1ffff10037a28e16 RSI: 0000000000000000 RDI: ffff8801bbea8b10 RBP: ffff8801bd147058 R08: 0000000000000000 R09: ffffed003780f27b R10: ffffffff89b58220 R11: 0000000000000001 R12: ffff8801bbea8b00 R13: ffff8801db02cc98 R14: ffff8801db02cc98 R15: 0000000000000000 FS: 000000c4200883e8(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001bce9b000 CR4: 00000000001406f0 Call Trace: __lock_release kernel/locking/lockdep.c:3670 [inline] lock_release+0x293/0x9f0 kernel/locking/lockdep.c:3920 prepare_lock_switch kernel/sched/core.c:2560 [inline] context_switch kernel/sched/core.c:2822 [inline] __schedule+0x84e/0x1df0 kernel/sched/core.c:3473 schedule+0xfb/0x450 kernel/sched/core.c:3517 freezable_schedule include/linux/freezer.h:172 [inline] futex_wait_queue_me+0x3f9/0x840 kernel/futex.c:2530 futex_wait+0x45b/0xa20 kernel/futex.c:2645 do_futex+0x336/0x27d0 kernel/futex.c:3528 __do_sys_futex kernel/futex.c:3589 [inline] __se_sys_futex kernel/futex.c:3557 [inline] __x64_sys_futex+0x472/0x6a0 kernel/futex.c:3557 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45ddf3 Code: cc cc cc cc cc cc cc 48 8b 7c 24 08 8b 74 24 10 8b 54 24 14 4c 8b 54 24 18 4c 8b 44 24 20 44 8b 4c 24 28 b8 ca 00 00 00 0f 05 <89> 44 24 30 c3 cc cc cc cc cc cc cc cc 8b 7c 24 08 48 8b 74 24 10 RSP: 002b:000000c420213ea8 EFLAGS: 00000206 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00000000000186a0 RCX: 000000000045ddf3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001494c28 RBP: 000000c420213ef0 R08: 0000000000000000 R09: 0000000000000000 R10: 000000c420213ee0 R11: 0000000000000206 R12: 0000000000000001 R13: 000000c420058240 R14: 0000000000000001 R15: 0000000000000000