Date:   Tue, 06 Aug 2019 20:18:05 -0700
From:   syzbot <syzbot+370e4739fa489334a4ef@...kaller.appspotmail.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        netdev@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: WARNING in cgroup_rstat_updated

Hello,

syzbot found the following crash on:

HEAD commit:    31cc088a Merge tag 'drm-next-2019-07-19' of git://anongit...
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=102db48c600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4dba67bf8b8c9ad7
dashboard link: https://syzkaller.appspot.com/bug?extid=370e4739fa489334a4ef
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16dd57dc600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+370e4739fa489334a4ef@...kaller.appspotmail.com

8021q: adding VLAN 0 to HW filter on device batadv0
WARNING: CPU: 1 PID: 9095 at mm/page_counter.c:62 page_counter_cancel  
mm/page_counter.c:62 [inline]
WARNING: CPU: 1 PID: 9095 at mm/page_counter.c:62  
page_counter_cancel+0x5a/0x70 mm/page_counter.c:55
Kernel panic - not syncing: panic_on_warn set ...
Shutting down cpus with NMI
Kernel Offset: disabled

======================================================
WARNING: possible circular locking dependency detected
5.2.0+ #67 Not tainted
------------------------------------------------------
syz-executor.2/9306 is trying to acquire lock:
00000000e4252251 ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70  
kernel/locking/semaphore.c:135

but task is already holding lock:
000000000fdb8781 (per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)){-...}, at:  
cgroup_rstat_updated+0x115/0x2f0 kernel/cgroup/rstat.c:49

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)){-...}:
        __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
        _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159
        cgroup_rstat_updated+0x115/0x2f0 kernel/cgroup/rstat.c:49
        cgroup_base_stat_cputime_account_end.isra.0+0x1d/0x60  
kernel/cgroup/rstat.c:361
        __cgroup_account_cputime+0x9e/0xd0 kernel/cgroup/rstat.c:371
        cgroup_account_cputime include/linux/cgroup.h:782 [inline]
        update_curr+0x3c8/0x8d0 kernel/sched/fair.c:862
        dequeue_entity+0x1e/0x1100 kernel/sched/fair.c:4014
        dequeue_task_fair+0x65/0x870 kernel/sched/fair.c:5306
        dequeue_task+0x77/0x2e0 kernel/sched/core.c:1195
        sched_move_task+0x1fb/0x350 kernel/sched/core.c:6847
        cpu_cgroup_attach+0x6d/0xb0 kernel/sched/core.c:6970
        cgroup_migrate_execute+0xc56/0x1350 kernel/cgroup/cgroup.c:2524
        cgroup_migrate+0x14f/0x1f0 kernel/cgroup/cgroup.c:2780
        cgroup_attach_task+0x57f/0x860 kernel/cgroup/cgroup.c:2817
        cgroup_procs_write+0x340/0x400 kernel/cgroup/cgroup.c:4777
        cgroup_file_write+0x241/0x790 kernel/cgroup/cgroup.c:3754
        kernfs_fop_write+0x2b8/0x480 fs/kernfs/file.c:315
        __vfs_write+0x8a/0x110 fs/read_write.c:494
        vfs_write+0x268/0x5d0 fs/read_write.c:558
        ksys_write+0x14f/0x290 fs/read_write.c:611
        __do_sys_write fs/read_write.c:623 [inline]
        __se_sys_write fs/read_write.c:620 [inline]
        __x64_sys_write+0x73/0xb0 fs/read_write.c:620
        do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
        entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #2 (&rq->lock){-.-.}:
        __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
        _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
        rq_lock kernel/sched/sched.h:1207 [inline]
        task_fork_fair+0x6a/0x520 kernel/sched/fair.c:9940
        sched_fork+0x3af/0x900 kernel/sched/core.c:2783
        copy_process+0x1b04/0x6b00 kernel/fork.c:1987
        _do_fork+0x146/0xfa0 kernel/fork.c:2369
        kernel_thread+0xbb/0xf0 kernel/fork.c:2456
        rest_init+0x28/0x37b init/main.c:417
        arch_call_rest_init+0xe/0x1b
        start_kernel+0x912/0x951 init/main.c:785
        x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:472
        x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:453
        secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

-> #1 (&p->pi_lock){-.-.}:
        __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
        _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159
        try_to_wake_up+0xb0/0x1aa0 kernel/sched/core.c:2432
        wake_up_process+0x10/0x20 kernel/sched/core.c:2548
        __up.isra.0+0x136/0x1a0 kernel/locking/semaphore.c:261
        up+0x9c/0xe0 kernel/locking/semaphore.c:186
        __up_console_sem+0xb7/0x1c0 kernel/printk/printk.c:244
        console_unlock+0x695/0xf10 kernel/printk/printk.c:2481
        vprintk_emit+0x2a0/0x700 kernel/printk/printk.c:1986
        vprintk_default+0x28/0x30 kernel/printk/printk.c:2013
        vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:386
        printk+0xba/0xed kernel/printk/printk.c:2046
        check_stack_usage kernel/exit.c:765 [inline]
        do_exit.cold+0x18b/0x314 kernel/exit.c:927
        do_group_exit+0x135/0x360 kernel/exit.c:981
        __do_sys_exit_group kernel/exit.c:992 [inline]
        __se_sys_exit_group kernel/exit.c:990 [inline]
        __x64_sys_exit_group+0x44/0x50 kernel/exit.c:990
        do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
        entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 ((console_sem).lock){-.-.}:
        check_prev_add kernel/locking/lockdep.c:2405 [inline]
        check_prevs_add kernel/locking/lockdep.c:2507 [inline]
        validate_chain kernel/locking/lockdep.c:2897 [inline]
        __lock_acquire+0x25a9/0x4c30 kernel/locking/lockdep.c:3880
        lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413
        __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
        _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159
        down_trylock+0x13/0x70 kernel/locking/semaphore.c:135
        __down_trylock_console_sem+0xa8/0x210 kernel/printk/printk.c:227
        console_trylock+0x15/0xa0 kernel/printk/printk.c:2297
        console_trylock_spinning kernel/printk/printk.c:1706 [inline]
        vprintk_emit+0x283/0x700 kernel/printk/printk.c:1985
        vprintk_default+0x28/0x30 kernel/printk/printk.c:2013
        vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:386
        printk+0xba/0xed kernel/printk/printk.c:2046
        kasan_die_handler arch/x86/mm/kasan_init_64.c:254 [inline]
        kasan_die_handler.cold+0x11/0x23 arch/x86/mm/kasan_init_64.c:249
        notifier_call_chain+0xc2/0x230 kernel/notifier.c:95
        __atomic_notifier_call_chain+0xa6/0x1a0 kernel/notifier.c:185
        atomic_notifier_call_chain kernel/notifier.c:195 [inline]
        notify_die+0xfb/0x180 kernel/notifier.c:551
        do_general_protection+0x13d/0x300 arch/x86/kernel/traps.c:558
        general_protection+0x1e/0x30 arch/x86/entry/entry_64.S:1181
        cgroup_rstat_updated+0x174/0x2f0 kernel/cgroup/rstat.c:64
        cgroup_base_stat_cputime_account_end.isra.0+0x1d/0x60  
kernel/cgroup/rstat.c:361
        __cgroup_account_cputime_field+0xd3/0x130 kernel/cgroup/rstat.c:395
        cgroup_account_cputime_field include/linux/cgroup.h:797 [inline]
        task_group_account_field kernel/sched/cputime.c:109 [inline]
        account_system_index_time+0x1f7/0x390 kernel/sched/cputime.c:172
        irqtime_account_process_tick.isra.0+0x386/0x490  
kernel/sched/cputime.c:389
        account_process_tick+0x27f/0x350 kernel/sched/cputime.c:484
        update_process_times+0x25/0x80 kernel/time/timer.c:1637
        tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
        tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1296
        __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
        __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1451
        hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
        local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1068 [inline]
        smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1093
        apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828

other info that might help us debug this:

Chain exists of:
   (console_sem).lock --> &rq->lock --> per_cpu_ptr(&cgroup_rstat_cpu_lock,  
cpu)

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu));
                                lock(&rq->lock);
                                lock(per_cpu_ptr(&cgroup_rstat_cpu_lock,  
cpu));
   lock((console_sem).lock);

  *** DEADLOCK ***

6 locks held by syz-executor.2/9306:
  #0: 0000000032d2cedf (&sb->s_type->i_mutex_key#12){+.+.}, at: inode_lock  
include/linux/fs.h:778 [inline]
  #0: 0000000032d2cedf (&sb->s_type->i_mutex_key#12){+.+.}, at:  
__sock_release+0x89/0x280 net/socket.c:589
  #1: 000000002033d24d (sk_lock-AF_INET6){+.+.}, at: lock_sock  
include/net/sock.h:1522 [inline]
  #1: 000000002033d24d (sk_lock-AF_INET6){+.+.}, at: tcp_close+0x27/0x10e0  
net/ipv4/tcp.c:2329
  #2: 0000000067f2fc6a (rcu_read_lock){....}, at: tcp_bpf_unhash+0x0/0x390  
net/ipv4/tcp_bpf.c:480
  #3: 0000000067f2fc6a (rcu_read_lock){....}, at: arch_atomic64_add  
arch/x86/include/asm/atomic64_64.h:46 [inline]
  #3: 0000000067f2fc6a (rcu_read_lock){....}, at: atomic64_add  
include/asm-generic/atomic-instrumented.h:873 [inline]
  #3: 0000000067f2fc6a (rcu_read_lock){....}, at: account_group_system_time  
include/linux/sched/cputime.h:154 [inline]
  #3: 0000000067f2fc6a (rcu_read_lock){....}, at:  
account_system_index_time+0xf7/0x390 kernel/sched/cputime.c:169
  #4: 000000000fdb8781 (per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)){-...}, at:  
cgroup_rstat_updated+0x115/0x2f0 kernel/cgroup/rstat.c:49
  #5: 0000000067f2fc6a (rcu_read_lock){....}, at:  
__atomic_notifier_call_chain+0x0/0x1a0 kernel/notifier.c:404

stack backtrace:
CPU: 0 PID: 9306 Comm: syz-executor.2 Not tainted 5.2.0+ #67
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  <IRQ>
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
  print_circular_bug.cold+0x163/0x172 kernel/locking/lockdep.c:1617
  check_noncircular+0x345/0x3e0 kernel/locking/lockdep.c:1741
  check_prev_add kernel/locking/lockdep.c:2405 [inline]
  check_prevs_add kernel/locking/lockdep.c:2507 [inline]
  validate_chain kernel/locking/lockdep.c:2897 [inline]
  __lock_acquire+0x25a9/0x4c30 kernel/locking/lockdep.c:3880
  lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159
  down_trylock+0x13/0x70 kernel/locking/semaphore.c:135
  __down_trylock_console_sem+0xa8/0x210 kernel/printk/printk.c:227
  console_trylock+0x15/0xa0 kernel/printk/printk.c:2297
  console_trylock_spinning kernel/printk/printk.c:1706 [inline]
  vprintk_emit+0x283/0x700 kernel/printk/printk.c:1985
  vprintk_default+0x28/0x30 kernel/printk/printk.c:2013
  vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:386
  printk+0xba/0xed kernel/printk/printk.c:2046
  kasan_die_handler arch/x86/mm/kasan_init_64.c:254 [inline]
  kasan_die_handler.cold+0x11/0x23 arch/x86/mm/kasan_init_64.c:249
  notifier_call_chain+0xc2/0x230 kernel/notifier.c:95
  __atomic_notifier_call_chain+0xa6/0x1a0 kernel/notifier.c:185
  atomic_notifier_call_chain kernel/notifier.c:195 [inline]
  notify_die+0xfb/0x180 kernel/notifier.c:551
  do_general_protection+0x13d/0x300 arch/x86/kernel/traps.c:558
  general_protection+0x1e/0x30 arch/x86/entry/entry_64.S:1181
RIP: 0010:cgroup_rstat_updated+0x174/0x2f0 kernel/cgroup/rstat.c:64
Code: 00 fc ff df 48 8b 45 c0 48 c1 e8 03 4c 01 f8 48 89 45 c8 eb 60 e8 6c  
e1 05 00 49 8d 7c 24 30 48 8b 55 d0 49 89 f9 49 c1 e9 03 <43> 80 3c 39 00  
0f 85 00 01 00 00 49 8b 7c 24 30 48 89 7a 38 49 8d
RSP: 0018:ffff8880ae809c08 EFLAGS: 00010006
RAX: ffff88809378a480 RBX: 0000000000000000 RCX: ffffffff8159c5ca
RDX: ffff8880ae800000 RSI: ffffffff816ca374 RDI: 47ff8883313e8861
RBP: ffff8880ae809c58 R08: 0000000000000004 R09: 08fff1106627d10c
R10: ffffed1015d0136d R11: 0000000000000003 R12: 47ff8883313e8831
R13: ffff88807b60a280 R14: ffffffff8626cbf5 R15: dffffc0000000000
  cgroup_base_stat_cputime_account_end.isra.0+0x1d/0x60  
kernel/cgroup/rstat.c:361
  __cgroup_account_cputime_field+0xd3/0x130 kernel/cgroup/rstat.c:395
  cgroup_account_cputime_field include/linux/cgroup.h:797 [inline]
  task_group_account_field kernel/sched/cputime.c:109 [inline]
  account_system_index_time+0x1f7/0x390 kernel/sched/cputime.c:172
  irqtime_account_process_tick.isra.0+0x386/0x490 kernel/sched/cputime.c:389
  account_process_tick+0x27f/0x350 kernel/sched/cputime.c:484
  update_process_times+0x25/0x80 kernel/time/timer.c:1637
  tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
  tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1296
  __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
  __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1451
  hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1068 [inline]
  smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1093
  apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828
  </IRQ>
Rebooting in 86400 seconds..


---
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