syzbot

==================================================================
kasan: CONFIG_KASAN_INLINE enabled
BUG: KASAN: stack-out-of-bounds in timerqueue_add+0x2a5/0x320 lib/timerqueue.c:52
kasan: GPF could be caused by NULL-ptr deref or user memory access
Read of size 8 at addr ffff8880a941f478 by task syz-executor881/7978
general protection fault: 0000 [#1] PREEMPT SMP KASAN

CPU: 1 PID: 3 Comm:  Not tainted 4.20.0-rc7-next-20181224 #1
CPU: 0 PID: 7978 Comm: syz-executor881 Not tainted 4.20.0-rc7-next-20181224 #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:191 [inline]
RIP: 0010:get_running_cputimer include/linux/sched/cputime.h:85 [inline]
RIP: 0010:account_group_system_time include/linux/sched/cputime.h:149 [inline]
RIP: 0010:account_system_index_time+0xe8/0x5f0 kernel/sched/cputime.c:168
Call Trace:
Code: 04 00 00 49 8b 84 24 00 07 00 00 48 ba 00 00 00 00 00 fc ff df 48 8d b8 40 01 00 00 48 8d 88 28 01 00 00 48 89 fe 48 c1 ee 03 <0f> b6 14 16 48 89 fe 83 e6 07 40 38 f2 7f 08 84 d2 0f 85 93 03 00
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1db/0x2d0 lib/dump_stack.c:113
RSP: 0018:ffff8880ae707a80 EFLAGS: 00010006
RAX: 0000000041b58ab3 RBX: 1ffff11015ce0f54 RCX: 0000000041b58bdb
RDX: dffffc0000000000 RSI: 000000000836b17e RDI: 0000000041b58bf3
RBP: ffff8880ae707b48 R08: ffff8880ae71f5f0 R09: fffffbfff1335b3d
R10: fffffbfff1301b45 R11: ffffffff899ad9e3 R12: ffff8880a94c4440
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
R13: 000000000077a391 R14: 0000000000000003 R15: ffff8880ae707b20
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
CR2: 00000000006d7090 CR3: 0000000096f60000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
Call Trace:
 timerqueue_add+0x2a5/0x320 lib/timerqueue.c:52
 <IRQ>
 enqueue_hrtimer+0x1ae/0x570 kernel/time/hrtimer.c:951
 __hrtimer_start_range_ns kernel/time/hrtimer.c:1080 [inline]
 hrtimer_start_range_ns+0x62a/0xda0 kernel/time/hrtimer.c:1106
 irqtime_account_process_tick.isra.0+0x3a2/0x490 kernel/sched/cputime.c:380
 account_process_tick+0x27f/0x350 kernel/sched/cputime.c:483
 update_process_times+0x25/0x80 kernel/time/timer.c:1633
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161
 hrtimer_start_expires include/linux/hrtimer.h:409 [inline]
 do_nanosleep+0x1a2/0x750 kernel/time/hrtimer.c:1676
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x3a7/0x1050 kernel/time/hrtimer.c:1451
 hrtimer_nanosleep+0x2e4/0x640 kernel/time/hrtimer.c:1733
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0x18d/0x760 arch/x86/kernel/apic/apic.c:1060
 __do_sys_nanosleep kernel/time/hrtimer.c:1767 [inline]
 __se_sys_nanosleep kernel/time/hrtimer.c:1754 [inline]
 __x64_sys_nanosleep+0x1e0/0x280 kernel/time/hrtimer.c:1754
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
Modules linked in:
RIP: 0033:0x443ae0

======================================================
WARNING: possible circular locking dependency detected
4.20.0-rc7-next-20181224 #1 Not tainted
------------------------------------------------------
syz-executor881/7978 is trying to acquire lock:
000000007874c6ae ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
000000001e99e9d7 (report_lock){....}, at: start_report mm/kasan/report.c:85 [inline]
000000001e99e9d7 (report_lock){....}, at: kasan_report+0xb1/0x15e mm/kasan/report.c:309

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (report_lock){....}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152
       start_report mm/kasan/report.c:85 [inline]
       kasan_report+0xb1/0x15e mm/kasan/report.c:309
       __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
       timerqueue_add+0x2a5/0x320 lib/timerqueue.c:52
       enqueue_hrtimer+0x1ae/0x570 kernel/time/hrtimer.c:951
       __hrtimer_start_range_ns kernel/time/hrtimer.c:1080 [inline]
       hrtimer_start_range_ns+0x62a/0xda0 kernel/time/hrtimer.c:1106
       hrtimer_start_expires include/linux/hrtimer.h:409 [inline]
       do_nanosleep+0x1a2/0x750 kernel/time/hrtimer.c:1676
       hrtimer_nanosleep+0x2e4/0x640 kernel/time/hrtimer.c:1733
       __do_sys_nanosleep kernel/time/hrtimer.c:1767 [inline]
       __se_sys_nanosleep kernel/time/hrtimer.c:1754 [inline]
       __x64_sys_nanosleep+0x1e0/0x280 kernel/time/hrtimer.c:1754
       do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #4 (hrtimer_bases.lock){-.-.}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152
       lock_hrtimer_base.isra.0+0x75/0x130 kernel/time/hrtimer.c:165
       hrtimer_start_range_ns+0x120/0xda0 kernel/time/hrtimer.c:1104
       hrtimer_start_expires include/linux/hrtimer.h:409 [inline]
       start_rt_bandwidth kernel/sched/rt.c:70 [inline]
       inc_rt_group kernel/sched/rt.c:1147 [inline]
       inc_rt_tasks kernel/sched/rt.c:1191 [inline]
       __enqueue_rt_entity kernel/sched/rt.c:1261 [inline]
       enqueue_rt_entity kernel/sched/rt.c:1305 [inline]
       enqueue_task_rt+0x95b/0x1010 kernel/sched/rt.c:1335
       enqueue_task+0xb9/0x380 kernel/sched/core.c:730
       __sched_setscheduler+0xe32/0x1fe0 kernel/sched/core.c:4336
       _sched_setscheduler+0x218/0x340 kernel/sched/core.c:4373
       sched_setscheduler+0xe/0x10 kernel/sched/core.c:4388
       watchdog_dev_init+0x109/0x1db drivers/watchdog/watchdog_dev.c:1144
       watchdog_init+0x81/0x294 drivers/watchdog/watchdog_core.c:355
       do_one_initcall+0x129/0x937 init/main.c:888
       do_initcall_level init/main.c:956 [inline]
       do_initcalls init/main.c:964 [inline]
       do_basic_setup init/main.c:982 [inline]
       kernel_init_freeable+0x4db/0x5ca init/main.c:1135
       kernel_init+0x12/0x1c5 init/main.c:1055
       ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

-> #3 (&rt_b->rt_runtime_lock){-.-.}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144
       __enable_runtime kernel/sched/rt.c:786 [inline]
       rq_online_rt+0xb4/0x390 kernel/sched/rt.c:2178
       set_rq_online.part.0+0xe7/0x140 kernel/sched/core.c:5666
       set_rq_online kernel/sched/core.c:5772 [inline]
       sched_cpu_activate+0x29e/0x430 kernel/sched/core.c:5765
       cpuhp_invoke_callback+0x2f6/0x2110 kernel/cpu.c:168
       cpuhp_thread_fun+0x496/0x8a0 kernel/cpu.c:685
       smpboot_thread_fn+0x6ab/0xa10 kernel/smpboot.c:164
       kthread+0x357/0x430 kernel/kthread.c:246
       ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

-> #2 (&rq->lock){-.-.}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144
       rq_lock kernel/sched/sched.h:1149 [inline]
       task_fork_fair+0xb5/0x7a0 kernel/sched/fair.c:10083
       sched_fork+0x437/0xb90 kernel/sched/core.c:2359
       copy_process+0x1ff6/0x8720 kernel/fork.c:1887
       _do_fork+0x1a9/0x1170 kernel/fork.c:2216
       kernel_thread+0x34/0x40 kernel/fork.c:2275
       rest_init+0x28/0x37b init/main.c:408
       arch_call_rest_init+0xe/0x1b
       start_kernel+0x882/0x8bd init/main.c:740
       x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470
       x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451
       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:152
       try_to_wake_up+0xb9/0x1480 kernel/sched/core.c:1965
       wake_up_process+0x10/0x20 kernel/sched/core.c:2129
       __up.isra.0+0x1c0/0x2a0 kernel/locking/semaphore.c:262
       up+0x13e/0x1c0 kernel/locking/semaphore.c:187
       __up_console_sem+0xb7/0x1c0 kernel/printk/printk.c:236
       console_unlock+0x743/0x1040 kernel/printk/printk.c:2473
       vprintk_emit+0x370/0x960 kernel/printk/printk.c:1978
       vprintk_default+0x28/0x30 kernel/printk/printk.c:2005
       vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398
       printk+0xba/0xed kernel/printk/printk.c:2038
       check_stack_usage kernel/exit.c:755 [inline]
       do_exit.cold+0x57/0x16a kernel/exit.c:916
       do_group_exit+0x177/0x430 kernel/exit.c:970
       __do_sys_exit_group kernel/exit.c:981 [inline]
       __se_sys_exit_group kernel/exit.c:979 [inline]
       __x64_sys_exit_group+0x44/0x50 kernel/exit.c:979
       do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 ((console_sem).lock){-.-.}:
       lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152
       down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
       __down_trylock_console_sem+0xa8/0x210 kernel/printk/printk.c:219
       console_trylock+0x15/0xa0 kernel/printk/printk.c:2289
       console_trylock_spinning kernel/printk/printk.c:1709 [inline]
       vprintk_emit+0x351/0x960 kernel/printk/printk.c:1977
       vprintk_default+0x28/0x30 kernel/printk/printk.c:2005
       vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398
       printk+0xba/0xed kernel/printk/printk.c:2038
       start_report mm/kasan/report.c:86 [inline]
       kasan_report+0xc1/0x15e mm/kasan/report.c:309
       __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
       timerqueue_add+0x2a5/0x320 lib/timerqueue.c:52
       enqueue_hrtimer+0x1ae/0x570 kernel/time/hrtimer.c:951
       __hrtimer_start_range_ns kernel/time/hrtimer.c:1080 [inline]
       hrtimer_start_range_ns+0x62a/0xda0 kernel/time/hrtimer.c:1106
       hrtimer_start_expires include/linux/hrtimer.h:409 [inline]
       do_nanosleep+0x1a2/0x750 kernel/time/hrtimer.c:1676
       hrtimer_nanosleep+0x2e4/0x640 kernel/time/hrtimer.c:1733
       __do_sys_nanosleep kernel/time/hrtimer.c:1767 [inline]
       __se_sys_nanosleep kernel/time/hrtimer.c:1754 [inline]
       __x64_sys_nanosleep+0x1e0/0x280 kernel/time/hrtimer.c:1754
       do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

Chain exists of:
  (console_sem).lock --> hrtimer_bases.lock --> report_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(report_lock);
                               lock(hrtimer_bases.lock);
                               lock(report_lock);
  lock((console_sem).lock);

 *** DEADLOCK ***

2 locks held by syz-executor881/7978:
 #0: 0000000053a4f5fc (hrtimer_bases.lock){-.-.}, at: lock_hrtimer_base.isra.0+0x75/0x130 kernel/time/hrtimer.c:165
 #1: 000000001e99e9d7 (report_lock){....}, at: start_report mm/kasan/report.c:85 [inline]
 #1: 000000001e99e9d7 (report_lock){....}, at: kasan_report+0xb1/0x15e mm/kasan/report.c:309

stack backtrace:
CPU: 0 PID: 7978 Comm: syz-executor881 Not tainted 4.20.0-rc7-next-20181224 #1
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+0x1db/0x2d0 lib/dump_stack.c:113
 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1224
 check_prev_add kernel/locking/lockdep.c:1866 [inline]
 check_prevs_add kernel/locking/lockdep.c:1979 [inline]
 validate_chain kernel/locking/lockdep.c:2350 [inline]
 __lock_acquire+0x2fed/0x4a10 kernel/locking/lockdep.c:3338
 lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152
 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
 __down_trylock_console_sem+0xa8/0x210 kernel/printk/printk.c:219
 console_trylock+0x15/0xa0 kernel/printk/printk.c:2289
 console_trylock_spinning kernel/printk/printk.c:1709 [inline]
 vprintk_emit+0x351/0x960 kernel/printk/printk.c:1977
 vprintk_default+0x28/0x30 kernel/printk/printk.c:2005
 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398
 printk+0xba/0xed kernel/printk/printk.c:2038
 start_report mm/kasan/report.c:86 [inline]
 kasan_report+0xc1/0x15e mm/kasan/report.c:309
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 timerqueue_add+0x2a5/0x320 lib/timerqueue.c:52
 enqueue_hrtimer+0x1ae/0x570 kernel/time/hrtimer.c:951
 __hrtimer_start_range_ns kernel/time/hrtimer.c:1080 [inline]
 hrtimer_start_range_ns+0x62a/0xda0 kernel/time/hrtimer.c:1106
 hrtimer_start_expires include/linux/hrtimer.h:409 [inline]
 do_nanosleep+0x1a2/0x750 kernel/time/hrtimer.c:1676
 hrtimer_nanosleep+0x2e4/0x640 kernel/time/hrtimer.c:1733
 __do_sys_nanosleep kernel/time/hrtimer.c:1767 [inline]
 __se_sys_nanosleep kernel/time/hrtimer.c:1754 [inline]
 __x64_sys_nanosleep+0x1e0/0x280 kernel/time/hrtimer.c:1754
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443ae0
Code: c0 5b 5d c3 66 0f 1f 44 00 00 8b 04 24 48 83 c4 18 5b 5d c3 66 0f 1f 44 00 00 83 3d 11 b5 29 00 00 75 14 b8 23 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 74 21 fc ff c3 48 83 ec 08 e8 4a 44 00 00
RSP: 002b:00007ffc84f7ff38 EFLAGS: 00000246 ORIG_RAX: 0000000000000023
RAX: ffffffffffffffda RBX: 0000000000000978 RCX: 0000000000443ae0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffc84f7ff40
RBP: 0000000000000978 R08: 0000000000000001 R09: 0000000001e99940
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000976
R13: 0000000000127235 R14: 0000000000000000 R15: 0000000000000000
---[ end trace 45e69f5e272f25f9 ]---
Code: c0 5b 5d c3 66 0f 1f 44 00 00 8b 04 24 48 83 c4 18 5b 5d c3 66 0f 1f 44 00 00 83 3d 11 b5 29 00 00 75 14 b8 23 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 74 21 fc ff c3 48 83 ec 08 e8 4a 44 00 00
RIP: 0010:__read_once_size include/linux/compiler.h:191 [inline]
RIP: 0010:get_running_cputimer include/linux/sched/cputime.h:85 [inline]
RIP: 0010:account_group_system_time include/linux/sched/cputime.h:149 [inline]
RIP: 0010:account_system_index_time+0xe8/0x5f0 kernel/sched/cputime.c:168
RSP: 002b:00007ffc84f7ff38 EFLAGS: 00000246 ORIG_RAX: 0000000000000023
Code: 04 00 00 49 8b 84 24 00 07 00 00 48 ba 00 00 00 00 00 fc ff df 48 8d b8 40 01 00 00 48 8d 88 28 01 00 00 48 89 fe 48 c1 ee 03 <0f> b6 14 16 48 89 fe 83 e6 07 40 38 f2 7f 08 84 d2 0f 85 93 03 00
RAX: ffffffffffffffda RBX: 0000000000000978 RCX: 0000000000443ae0
RSP: 0018:ffff8880ae707a80 EFLAGS: 00010006
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffc84f7ff40
RAX: 0000000041b58ab3 RBX: 1ffff11015ce0f54 RCX: 0000000041b58bdb
RBP: 0000000000000978 R08: 0000000000000001 R09: 0000000001e99940
RDX: dffffc0000000000 RSI: 000000000836b17e RDI: 0000000041b58bf3
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000976
RBP: ffff8880ae707b48 R08: ffff8880ae71f5f0 R09: fffffbfff1335b3d
R13: 0000000000127235 R14: 0000000000000000 R15: 0000000000000000
R10: fffffbfff1301b45 R11: ffffffff899ad9e3 R12: ffff8880a94c4440

R13: 000000000077a391 R14: 0000000000000003 R15: ffff8880ae707b20
The buggy address belongs to the page:
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
page:ffffea0002a507c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
flags: 0x1fffc0000000000()
CR2: 00000000006d7090 CR3: 0000000096f60000 CR4: 00000000001406e0
raw: 01fffc0000000000 ffffea0002a507c8 ffffea0002a507c8 0000000000000000
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
page dumped because: kasan: bad access detected