Message-ID: <0000000000009551c40572d9a91e@google.com>
Date:   Tue, 07 Aug 2018 08:01:02 -0700
From:   syzbot <syzbot+0badcf87cb26aa6e5ea6@...kaller.appspotmail.com>
To:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        miklos@...redi.hu, syzkaller-bugs@...glegroups.com
Subject: INFO: rcu detected stall in native_queued_spin_lock_slowpath

Hello,

syzbot found the following crash on:

HEAD commit:    0585df468e8f Merge tag 'media/v4.18-3' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10edc89c400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2dc0cd7c2eefb46f
dashboard link: https://syzkaller.appspot.com/bug?extid=0badcf87cb26aa6e5ea6
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+0badcf87cb26aa6e5ea6@...kaller.appspotmail.com

INFO: rcu_sched detected stalls on CPUs/tasks:
	(detected by 0, t=105007 jiffies, g=118924, c=118923, q=65)
All QSes seen, last rcu_sched kthread activity 105014  
(4295296700-4295191686), jiffies_till_next_fqs=3, root ->qsmask 0x0
syz-executor7   R  running task    23352 14084   4424 0x00000008
Call Trace:
  <IRQ>
  sched_show_task.cold.84+0x27a/0x301 kernel/sched/core.c:5324
  print_other_cpu_stall.cold.77+0x92f/0x9d2 kernel/rcu/tree.c:1441
  check_cpu_stall.isra.60+0x721/0xf70 kernel/rcu/tree.c:1559
  __rcu_pending kernel/rcu/tree.c:3244 [inline]
  rcu_pending kernel/rcu/tree.c:3291 [inline]
  rcu_check_callbacks+0x23f/0xcd0 kernel/rcu/tree.c:2646
  update_process_times+0x2d/0x70 kernel/time/timer.c:1636
  tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164
  tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274
  __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
  __hrtimer_run_queues+0x3eb/0x10c0 kernel/time/hrtimer.c:1460
  hrtimer_interrupt+0x2f3/0x750 kernel/time/hrtimer.c:1518
  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1028 [inline]
  smp_apic_timer_interrupt+0x165/0x730 arch/x86/kernel/apic/apic.c:1053
  apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863
  </IRQ>
RIP: 0010:bytes_is_nonzero mm/kasan/kasan.c:167 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/kasan.c:184 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/kasan.c:210 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/kasan.c:241 [inline]
RIP: 0010:check_memory_region_inline mm/kasan/kasan.c:257 [inline]
RIP: 0010:check_memory_region+0x121/0x1b0 mm/kasan/kasan.c:267
Code: 29 c0 e9 6c ff ff ff 4d 85 c0 74 ba 48 b8 01 00 00 00 00 fc ff df 4d  
01 c8 48 01 d8 41 80 39 00 74 08 e9 8c 00 00 00 48 89 d8 <4c> 39 c0 74 97  
80 38 00 48 8d 58 01 74 ef eb 87 4c 89 c0 49 39 c2
RSP: 0018:ffff88018fec7388 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffed0039557a49 RBX: 1ffff10039557a48 RCX: ffffffff815faf29
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8801caabd240
RBP: ffff88018fec73a0 R08: ffffed0039557a49 R09: ffffed0039557a48
R10: ffffed0039557a48 R11: ffff8801caabd243 R12: ffffed0039557a49
R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8801caabd240
  kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
  atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
  virt_spin_lock arch/x86/include/asm/qspinlock.h:65 [inline]
  native_queued_spin_lock_slowpath+0x189/0x1200  
kernel/locking/qspinlock.c:305
  pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:674 [inline]
  queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:32 [inline]
  queued_spin_lock include/asm-generic/qspinlock.h:88 [inline]
  do_raw_spin_lock+0x1a7/0x200 kernel/locking/spinlock_debug.c:113
  __raw_spin_lock include/linux/spinlock_api_smp.h:143 [inline]
  _raw_spin_lock+0x32/0x40 kernel/locking/spinlock.c:144
  spin_lock include/linux/spinlock.h:310 [inline]
  request_end+0x400/0xb20 fs/fuse/dev.c:382
  end_requests+0x296/0x460 fs/fuse/dev.c:2045
  fuse_dev_release+0x18c/0x2e0 fs/fuse/dev.c:2154
  __fput+0x355/0x8b0 fs/file_table.c:209
  ____fput+0x15/0x20 fs/file_table.c:243
  task_work_run+0x1ec/0x2a0 kernel/task_work.c:113
  tracehook_notify_resume include/linux/tracehook.h:192 [inline]
  exit_to_usermode_loop+0x313/0x370 arch/x86/entry/common.c:166
  prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
  syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
  do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x456b29
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fae499f2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: 0000000000000030 RBX: 00007fae499f36d4 RCX: 0000000000456b29
RDX: 0000000000001000 RSI: 0000000020001000 RDI: 0000000000000017
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d2b40 R14: 00000000004c7b8b R15: 0000000000000000
rcu_sched kthread starved for 105755 jiffies! g118924 c118923 f0x2  
RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1
RCU grace-period kthread stack dump:
rcu_sched       R  running task    23688    10      2 0x80000000
Call Trace:
  context_switch kernel/sched/core.c:2853 [inline]
  __schedule+0x87c/0x1ec0 kernel/sched/core.c:3501
  schedule+0xfb/0x450 kernel/sched/core.c:3545
  schedule_timeout+0x140/0x260 kernel/time/timer.c:1801
  rcu_gp_kthread+0x717/0x1c90 kernel/rcu/tree.c:2179
  kthread+0x345/0x410 kernel/kthread.c:246
  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412


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