Message-ID: <000000000000418fc105aa4243aa@google.com>
Date:   Sun, 12 Jul 2020 10:54:16 -0700
From:   syzbot <syzbot+f3bd350a4124f10acdae@...kaller.appspotmail.com>
To:     linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com,
        tglx@...utronix.de
Subject: INFO: rcu detected stall in sys_clock_settime

Hello,

syzbot found the following crash on:

HEAD commit:    0bddd227 Documentation: update for gcc 4.9 requirement
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13178abd100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=66ad203c2bb6d8b
dashboard link: https://syzkaller.appspot.com/bug?extid=f3bd350a4124f10acdae
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1266a2fb100000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12fd03ff100000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+f3bd350a4124f10acdae@...kaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...0: (1 GPs behind) idle=b0e/1/0x4000000000000000 softirq=8473/8474 fqs=5249 
	(detected by 1, t=10502 jiffies, g=8021, q=3628)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6813 Comm: syz-executor178 Not tainted 5.8.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1145 [inline]
RIP: 0010:rcu_lockdep_current_cpu_online+0x44/0x110 kernel/rcu/tree.c:1136
Code: 85 d2 75 01 c3 55 53 48 83 ec 08 65 ff 05 74 44 a1 7e e8 af ed 83 06 48 c7 c3 00 6c 03 00 48 ba 00 00 00 00 00 fc ff df 89 c0 <48> 8d 3c c5 40 39 81 89 48 89 f9 48 c1 e9 03 80 3c 11 00 0f 85 82
RSP: 0018:ffffc90000007db8 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 0000000000036c00 RCX: 1ffffffff1302728
RDX: dffffc0000000000 RSI: 0000000000010004 RDI: 0000000000000000
RBP: 176b61322ed6c264 R08: 0000000000000000 R09: ffffffff8aae5b0f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: ffff8880ae627840 R14: ffff8880905ab340 R15: dffffc0000000000
FS:  0000000001834880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000610 CR3: 00000000a710b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_read_lock_held_common kernel/rcu/update.c:122 [inline]
 rcu_read_lock_held_common kernel/rcu/update.c:112 [inline]
 rcu_read_lock_sched_held+0x25/0xb0 kernel/rcu/update.c:133
 trace_hrtimer_cancel include/trace/events/timer.h:290 [inline]
 debug_deactivate kernel/time/hrtimer.c:483 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1488 [inline]
 __hrtimer_run_queues+0xd59/0xfc0 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x142/0x5e0 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+0xe0/0x120 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:587
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 [inline]
RIP: 0010:on_each_cpu+0x149/0x240 kernel/smp.c:702
Code: 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 e6 00 00 00 48 83 3d 97 12 4c 08 00 0f 84 af 00 00 00 e8 6c e9 0a 00 48 89 df 57 9d <0f> 1f 44 00 00 e8 5d e9 0a 00 bf 01 00 00 00 e8 83 a4 e6 ff 31 ff
RSP: 0018:ffffc90001477d70 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000293 RCX: 0000000000000000
RDX: ffff8880a7e2c100 RSI: ffffffff8168cdf4 RDI: 0000000000000293
RBP: 0000000000000200 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc90001477ed0 R15: ffffffffa0f8b034
 clock_was_set+0x18/0x20 kernel/time/hrtimer.c:872
 do_settimeofday64 kernel/time/timekeeping.c:1257 [inline]
 do_settimeofday64+0x350/0x4e0 kernel/time/timekeeping.c:1223
 do_sys_settimeofday64 kernel/time/time.c:195 [inline]
 do_sys_settimeofday64+0x1de/0x260 kernel/time/time.c:169
 __do_sys_clock_settime kernel/time/posix-timers.c:1079 [inline]
 __se_sys_clock_settime kernel/time/posix-timers.c:1067 [inline]
 __x64_sys_clock_settime+0x197/0x260 kernel/time/posix-timers.c:1067
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x443849
Code: Bad RIP value.
RSP: 002b:00007ffe4b8100d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000443849
RDX: 0000000000443849 RSI: 0000000020000400 RDI: 0000000000000000
RBP: 00007ffe4b8100e0 R08: 0000000001bbbbbb R09: 0000000001bbbbbb
R10: 0000000001bbbbbb R11: 0000000000000246 R12: 00007ffe4b8100f0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000


---
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