Date:   Tue, 07 Jul 2020 08:13:16 -0700
From:   syzbot <syzbot+25b7addb06e92c482190@...kaller.appspotmail.com>
To:     fweisbec@...il.com, linux-kernel@...r.kernel.org, mingo@...nel.org,
        syzkaller-bugs@...glegroups.com, tglx@...utronix.de
Subject: INFO: rcu detected stall in sys_clock_adjtime

Hello,

syzbot found the following crash on:

HEAD commit:    7cc2a8ea Merge tag 'block-5.8-2020-07-01' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1204932f100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=183dd243398ba7ec
dashboard link: https://syzkaller.appspot.com/bug?extid=25b7addb06e92c482190
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1531b0bd100000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15514c33100000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+25b7addb06e92c482190@...kaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
------------[ cut here ]------------
IRQs not enabled as expected
WARNING: CPU: 1 PID: 4737 at kernel/sched/core.c:2698 try_invoke_on_locked_down_task+0x18b/0x320 kernel/sched/core.c:2698
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 4737 Comm: systemd-timesyn Not tainted 5.8.0-rc3-syzkaller #0
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+0x1f0/0x31e lib/dump_stack.c:118
 panic+0x264/0x7a0 kernel/panic.c:231
 __warn+0x227/0x250 kernel/panic.c:600
 report_bug+0x1b1/0x2e0 lib/bug.c:198
 handle_bug+0x42/0x80 arch/x86/kernel/traps.c:235
 exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:255
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:563
RIP: 0010:try_invoke_on_locked_down_task+0x18b/0x320 kernel/sched/core.c:2698
Code: 48 89 df e8 a7 35 09 00 4c 89 f7 e8 3f 63 ce 06 e9 b5 00 00 00 c6 05 92 7d 18 08 01 48 c7 c7 fc a9 e7 88 31 c0 e8 65 a8 f5 ff <0f> 0b e9 15 ff ff ff 48 c7 c1 70 5d 6d 89 80 e1 07 80 c1 03 38 c1
RSP: 0018:ffffc90000da8c50 EFLAGS: 00010046
RAX: 82cfb6c0e4d32500 RBX: ffff888096c1ee08 RCX: ffff888096c1e580
RDX: 0000000000010004 RSI: 0000000000010004 RDI: 0000000000000000
RBP: ffff888096c1ee4c R08: ffffffff815dc419 R09: ffffed1015d241c3
R10: ffffed1015d241c3 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8880a9990040 R14: ffff8880a99903c0 R15: dffffc0000000000
 rcu_print_task_stall kernel/rcu/tree_stall.h:269 [inline]
 print_other_cpu_stall kernel/rcu/tree_stall.h:477 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:636 [inline]
 rcu_pending kernel/rcu/tree.c:3489 [inline]
 rcu_sched_clock_irq+0x12ec/0x1eb0 kernel/rcu/tree.c:2504
 update_process_times+0x12c/0x180 kernel/time/timer.c:1726
 tick_sched_handle kernel/time/tick-sched.c:176 [inline]
 tick_sched_timer+0x254/0x410 kernel/time/tick-sched.c:1320
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x42d/0x930 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0x373/0xd60 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0xf0/0x260 arch/x86/kernel/apic/apic.c:1097
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_apic_timer_interrupt+0xb9/0x130 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:596
RIP: 0010:csd_lock_wait kernel/smp.c:108 [inline]
RIP: 0010:smp_call_function_single+0x311/0x450 kernel/smp.c:382
Code: 83 e5 01 75 14 e8 4f 00 0b 00 eb 45 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f3 90 42 0f b6 04 23 84 c0 75 0d 41 f6 07 01 74 22 <e8> 2a 00 0b 00 eb e8 44 89 f9 80 e1 07 80 c1 03 38 c1 7c e6 4c 89
RSP: 0018:ffffc90001c27be0 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 1ffff92000384f81 RCX: ffff888096c1e580
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90001c27c80 R08: ffffffff81697bb6 R09: ffffed1015d06d11
R10: ffffed1015d06d11 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000000 R15: ffffc90001c27c08
 smp_call_function_many kernel/smp.c:577 [inline]
 smp_call_function kernel/smp.c:599 [inline]
 on_each_cpu+0x4d/0x1f0 kernel/smp.c:699
 clock_was_set+0x18/0x20 kernel/time/hrtimer.c:872
 timekeeping_inject_offset+0x5e6/0x610 kernel/time/timekeeping.c:1305
 do_adjtimex+0x3ac/0x8f0 kernel/time/timekeeping.c:2332
 do_clock_adjtime kernel/time/posix-timers.c:1109 [inline]
 __do_sys_clock_adjtime kernel/time/posix-timers.c:1121 [inline]
 __se_sys_clock_adjtime kernel/time/posix-timers.c:1112 [inline]
 __x64_sys_clock_adjtime+0x17e/0x210 kernel/time/posix-timers.c:1112
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f4117ebd1b7
Code: Bad RIP value.
RSP: 002b:00007ffeedde6cd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000131
RAX: ffffffffffffffda RBX: 000055f707897630 RCX: 00007f4117ebd1b7
RDX: ffffffffe7ce77f1 RSI: 00007ffeedde6da0 RDI: 0000000000000000
RBP: 00007ffeedde6da0 R08: 0000000000000020 R09: 000000000000000d
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00007ffeedde6e90 R14: 0000000000000005 R15: 0000000000000001
Shutting down cpus with NMI
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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