Message-ID: <CACT4Y+Y=i=9iezeaSoxcVoCYf69GwFqkkf7Qw23eN8218LPNnw@mail.gmail.com>
Date:   Tue, 12 Dec 2017 17:49:24 +0100
From:   Dmitry Vyukov <dvyukov@...gle.com>
To:     syzbot 
        <bot+73ca12738d47b49568eb6217b7386e2ce6cc26b0@...kaller.appspotmail.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        syzkaller-bugs@...glegroups.com, Jens Axboe <axboe@...nel.dk>,
        Ming Lei <tom.leiming@...il.com>,
        Omar Sandoval <osandov@...com>, Hannes Reinecke <hare@...e.de>,
        shli@...com
Subject: Re: INFO: task hung in truncate_inode_pages_range

On Sun, Dec 10, 2017 at 2:34 PM, syzbot
<bot+73ca12738d47b49568eb6217b7386e2ce6cc26b0@...kaller.appspotmail.com>
wrote:
> Hello,
>
> syzkaller hit the following crash on
> ad4dac17f9d563b9e34aab78a34293b10993e9b5
> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached
> Raw console output is attached.
>
> Unfortunately, I don't have any reproducer for this bug yet.
>
>
> INFO: task syz-executor6:9207 blocked for more than 120 seconds.
>       Not tainted 4.15.0-rc2-next-20171208+ #63
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> syz-executor6   D21264  9207   3394 0x80000002
> Call Trace:
>  context_switch kernel/sched/core.c:2800 [inline]
>  __schedule+0x8eb/0x2060 kernel/sched/core.c:3376
>  schedule+0xf5/0x430 kernel/sched/core.c:3435
>  io_schedule+0x1c/0x70 kernel/sched/core.c:5043
>  wait_on_page_bit_common mm/filemap.c:1099 [inline]
>  __lock_page+0x585/0x740 mm/filemap.c:1272
>  lock_page include/linux/pagemap.h:483 [inline]
>  truncate_inode_pages_range+0x1945/0x1f90 mm/truncate.c:452
>  truncate_inode_pages+0x24/0x30 mm/truncate.c:482
>  kill_bdev+0xbc/0xf0 fs/block_dev.c:86
>  __blkdev_put+0x183/0x7c0 fs/block_dev.c:1764
>  blkdev_put+0x85/0x4f0 fs/block_dev.c:1835
>  blkdev_close+0x91/0xc0 fs/block_dev.c:1842
>  __fput+0x333/0x7f0 fs/file_table.c:210
>  ____fput+0x15/0x20 fs/file_table.c:244
>  task_work_run+0x199/0x270 kernel/task_work.c:113
>  exit_task_work include/linux/task_work.h:22 [inline]
>  do_exit+0x9bb/0x1ae0 kernel/exit.c:869
>  do_group_exit+0x149/0x400 kernel/exit.c:972
>  get_signal+0x73f/0x16c0 kernel/signal.c:2337
>  do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809
>  exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:161
>  prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
>  syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
>  entry_SYSCALL_64_fastpath+0x94/0x96
> RIP: 0033:0x452a39
> RSP: 002b:00007f8d5a5edc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000028
> RAX: fffffffffffffffc RBX: 0000000000758020 RCX: 0000000000452a39
> RDX: 0000000020d10ff8 RSI: 000000000000001c RDI: 000000000000001c
> RBP: 000000000000045b R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000001 R11: 0000000000000212 R12: 00000000006f4928
> R13: 00000000ffffffff R14: 00007f8d5a5ee6d4 R15: 0000000000000000
>
> Showing all locks held in the system:
> 2 locks held by khungtaskd/671:
>  #0:  (rcu_read_lock){....}, at: [<00000000df4af4d1>]
> check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
>  #0:  (rcu_read_lock){....}, at: [<00000000df4af4d1>] watchdog+0x1c5/0xd60
> kernel/hung_task.c:249
>  #1:  (tasklist_lock){.+.+}, at: [<00000000b61748dc>]
> debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554
> 2 locks held by getty/3117:
>  #0:  (&tty->ldisc_sem){++++}, at: [<0000000083232a91>]
> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>  #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000884d0566>]
> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> 2 locks held by getty/3118:
>  #0:  (&tty->ldisc_sem){++++}, at: [<0000000083232a91>]
> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>  #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000884d0566>]
> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> 2 locks held by getty/3119:
>  #0:  (&tty->ldisc_sem){++++}, at: [<0000000083232a91>]
> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>  #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000884d0566>]
> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> 2 locks held by getty/3120:
>  #0:  (&tty->ldisc_sem){++++}, at: [<0000000083232a91>]
> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>  #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000884d0566>]
> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> 2 locks held by getty/3121:
>  #0:  (&tty->ldisc_sem){++++}, at: [<0000000083232a91>]
> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>  #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000884d0566>]
> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> 2 locks held by getty/3122:
>  #0:  (&tty->ldisc_sem){++++}, at: [<0000000083232a91>]
> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>  #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000884d0566>]
> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> 2 locks held by getty/3123:
>  #0:  (&tty->ldisc_sem){++++}, at: [<0000000083232a91>]
> ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
>  #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000884d0566>]
> n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
> 1 lock held by syz-executor6/9207:
>  #0:  (&bdev->bd_mutex){+.+.}, at: [<000000003bb9433b>]
> __blkdev_put+0xa7/0x7c0 fs/block_dev.c:1757
> 1 lock held by blkid/9235:
>  #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000dd49b480>]
> __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439
> 1 lock held by syz-executor6/9345:
>  #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000dd49b480>]
> __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439
> 1 lock held by syz-executor6/9346:
>  #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000dd49b480>]
> __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439
>
> =============================================
>
> NMI backtrace for cpu 0
> CPU: 0 PID: 671 Comm: khungtaskd Not tainted 4.15.0-rc2-next-20171208+ #63
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:17 [inline]
>  dump_stack+0x194/0x257 lib/dump_stack.c:53
>  nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
>  nmi_trigger_cpumask_backtrace+0x122/0x180 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+0x90c/0xd60 kernel/hung_task.c:249
>  kthread+0x37a/0x440 kernel/kthread.c:238
>  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:524
> Sending NMI from CPU 0 to CPUs 1:
> NMI backtrace for cpu 1
> CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc2-next-20171208+ #63
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> RIP: 0010:add_xhlock kernel/locking/lockdep.c:4871 [inline]
> RIP: 0010:check_add_xhlock kernel/locking/lockdep.c:4907 [inline]
> RIP: 0010:lock_acquire_crosslock kernel/locking/lockdep.c:4979 [inline]
> RIP: 0010:__lock_acquire+0x1f9e/0x47f0 kernel/locking/lockdep.c:3503
> RSP: 0018:ffff8801db306fe0 EFLAGS: 00000807
> RAX: 0000000000001e7b RBX: ffff8801d9f88b88 RCX: 0000000000000000
> RDX: 1ffff1003b3f1293 RSI: 1ffff1003b3f1101 RDI: ffff8801d9f8949c
> RBP: ffff8801db307368 R08: 0000000000000000 R09: 000000000000000c
> R10: 0000000000000000 R11: ffffffff87896ce0 R12: ffff8801d9f88300
> R13: ffff8801d9f8d4d8 R14: 9dd28c6188bbd6db R15: ffff8801d9f88300
> FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000016dd000 CR3: 00000001cceea000 CR4: 00000000001406e0
> DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
> Call Trace:
>  <IRQ>
>  lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004
>  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
>  _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:159
>  rq_lock_irqsave kernel/sched/sched.h:1750 [inline]
>  update_blocked_averages+0x124/0x1b60 kernel/sched/fair.c:7353
>  rebalance_domains+0x145/0xcc0 kernel/sched/fair.c:9122
>  run_rebalance_domains+0x381/0x780 kernel/sched/fair.c:9383
>  __do_softirq+0x29d/0xbb2 kernel/softirq.c:285
>  invoke_softirq kernel/softirq.c:365 [inline]
>  irq_exit+0x1d3/0x210 kernel/softirq.c:405
>  scheduler_ipi+0x32a/0x830 kernel/sched/core.c:1804
>  smp_reschedule_interrupt+0xe6/0x670 arch/x86/kernel/smp.c:277
>  reschedule_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:944
>  </IRQ>
> RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
> RSP: 0018:ffff8801d9f97da8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02
> RAX: dffffc0000000000 RBX: 1ffff1003b3f2fb8 RCX: 0000000000000000
> RDX: 1ffffffff0c5975c RSI: 0000000000000001 RDI: ffffffff862cbae0
> RBP: ffff8801d9f97da8 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
> R13: ffff8801d9f97e60 R14: ffffffff869efaa0 R15: 0000000000000000
>  arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline]
>  default_idle+0xbf/0x430 arch/x86/kernel/process.c:355
>  arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:346
>  default_idle_call+0x36/0x90 kernel/sched/idle.c:98
>  cpuidle_idle_call kernel/sched/idle.c:156 [inline]
>  do_idle+0x24a/0x3b0 kernel/sched/idle.c:246
>  cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:351
>  start_secondary+0x330/0x460 arch/x86/kernel/smpboot.c:277
>  secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237
> Code: 48 8b 43 08 48 89 fa 48 c1 ea 03 49 89 45 50 48 8b 43 10 49 89 45 58
> 48 8b 43 18 49 89 45 60 48 8b 43 20 49 89 45 68 48 8b 43 28 <49> 89 45 70 48
> b8 00 00 00 00 00 fc ff df 0f b6 14 02 48 89 f8


+loop maintainers

#syz dup: INFO: task hung in lo_ioctl


> ---
> This bug is generated by a dumb bot. It may contain errors.
> See https://goo.gl/tpsmEJ for details.
> Direct all questions to syzkaller@...glegroups.com.
> Please credit me with: Reported-by: syzbot <syzkaller@...glegroups.com>
>
> syzbot will keep track of this bug report.
> Once a fix for this bug is merged into any tree, reply to this email with:
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> To mark this as a duplicate of another syzbot report, please reply with:
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