* INFO: rcu detected stall in shrink_dentry_list
@ 2018-04-14 9:43 syzbot
2018-04-14 9:45 ` Dmitry Vyukov
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2018-04-14 9:43 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, syzkaller-bugs, viro
Hello,
syzbot hit the following crash on upstream commit
16e205cf42da1f497b10a4a24f563e6c0d574eec (Fri Apr 13 03:56:10 2018 +0000)
Merge tag 'drm-fixes-for-v4.17-rc1' of
git://people.freedesktop.org/~airlied/linux
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=9275da3e0f734e102b61
Unfortunately, I don't have any reproducer for this crash yet.
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=4692036947017728
Kernel config:
https://syzkaller.appspot.com/x/.config?id=-5947642240294114534
compiler: gcc (GCC) 8.0.1 20180301 (experimental)
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9275da3e0f734e102b61@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for
details.
If you forward the report, please keep this part and the footer.
INFO: rcu_sched self-detected stall on CPU
1-...!: (124995 ticks this GP) idle=b86/1/4611686018427387906
softirq=32196/32196 fqs=3
(t=125000 jiffies g=16751 c=16750 q=347)
rcu_sched kthread starved for 124987 jiffies! g16751 c16750 f0x0
RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1
RCU grace-period kthread stack dump:
rcu_sched R running task 23544 9 2 0x80000000
Call Trace:
context_switch kernel/sched/core.c:2848 [inline]
__schedule+0x801/0x1e30 kernel/sched/core.c:3490
schedule+0xef/0x430 kernel/sched/core.c:3549
schedule_timeout+0x138/0x240 kernel/time/timer.c:1801
rcu_gp_kthread+0x6b5/0x1940 kernel/rcu/tree.c:2231
kthread+0x345/0x410 kernel/kthread.c:238
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411
NMI backtrace for cpu 1
CPU: 1 PID: 4559 Comm: syz-executor6 Not tainted 4.16.0+ #2
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+0x1b9/0x294 lib/dump_stack.c:113
nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_single_cpu_backtrace include/linux/nmi.h:156 [inline]
rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1376
print_cpu_stall kernel/rcu/tree.c:1525 [inline]
check_cpu_stall.isra.61.cold.80+0x36c/0x59a kernel/rcu/tree.c:1593
__rcu_pending kernel/rcu/tree.c:3356 [inline]
rcu_pending kernel/rcu/tree.c:3401 [inline]
rcu_check_callbacks+0x21b/0xad0 kernel/rcu/tree.c:2763
update_process_times+0x2d/0x70 kernel/time/timer.c:1636
tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:173
tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1283
__run_hrtimer kernel/time/hrtimer.c:1386 [inline]
__hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1448
hrtimer_interrupt+0x286/0x650 kernel/time/hrtimer.c:1506
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:862
</IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x14/0x50 kernel/kcov.c:94
RSP: 0018:ffff88018e2e7a80 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff88018e2de680 RBX: ffff88018e2e7bf8 RCX: ffffffff81c2b1d9
RDX: 0000000000000000 RSI: ffffffff81c26bf3 RDI: ffff88018e2e7bf8
RBP: ffff88018e2e7a80 R08: ffff88018e2de680 R09: ffffed003b51c378
R10: ffffed003b51c378 R11: ffff8801da8e1bc3 R12: ffff88018e2e7c30
R13: dffffc0000000000 R14: 1ffff10031c5cf7e R15: ffffed0031c5cf81
shrink_dentry_list+0x5a8/0x7c0 fs/dcache.c:1087
shrink_dcache_parent+0xba/0x230 fs/dcache.c:1490
vfs_rmdir+0x202/0x470 fs/namei.c:3850
do_rmdir+0x523/0x610 fs/namei.c:3911
SYSC_rmdir fs/namei.c:3929 [inline]
SyS_rmdir+0x1a/0x20 fs/namei.c:3927
do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x455087
RSP: 002b:00007fff8b6b76b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 0000000000455087
RDX: 0000000000000000 RSI: 00007fff8b6b9460 RDI: 00007fff8b6b9460
RBP: 00007fff8b6b9460 R08: 0000000000000000 R09: 0000000000000001
R10: 000000000000000a R11: 0000000000000206 R12: 0000000002768940
R13: 0000000000000000 R14: 00000000000001ec R15: 000000000001984e
---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to syzkaller@googlegroups.com.
syzbot will keep track of this bug report.
If you forgot to add the Reported-by tag, once the fix for this bug is
merged
into any tree, please reply to this email with:
#syz fix: exact-commit-title
To mark this as a duplicate of another syzbot report, please reply with:
#syz dup: exact-subject-of-another-report
If it's a one-off invalid bug report, please reply with:
#syz invalid
Note: if the crash happens again, it will cause creation of a new bug
report.
Note: all commands must start from beginning of the line in the email body.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: INFO: rcu detected stall in shrink_dentry_list
2018-04-14 9:43 INFO: rcu detected stall in shrink_dentry_list syzbot
@ 2018-04-14 9:45 ` Dmitry Vyukov
0 siblings, 0 replies; 2+ messages in thread
From: Dmitry Vyukov @ 2018-04-14 9:45 UTC (permalink / raw)
To: syzbot; +Cc: linux-fsdevel, LKML, syzkaller-bugs, Al Viro, Tetsuo Handa
On Sat, Apr 14, 2018 at 11:43 AM, syzbot
<syzbot+9275da3e0f734e102b61@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot hit the following crash on upstream commit
> 16e205cf42da1f497b10a4a24f563e6c0d574eec (Fri Apr 13 03:56:10 2018 +0000)
> Merge tag 'drm-fixes-for-v4.17-rc1' of
> git://people.freedesktop.org/~airlied/linux
> syzbot dashboard link:
> https://syzkaller.appspot.com/bug?extid=9275da3e0f734e102b61
>
> Unfortunately, I don't have any reproducer for this crash yet.
> Raw console output:
> https://syzkaller.appspot.com/x/log.txt?id=4692036947017728
> Kernel config:
> https://syzkaller.appspot.com/x/.config?id=-5947642240294114534
> compiler: gcc (GCC) 8.0.1 20180301 (experimental)
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+9275da3e0f734e102b61@syzkaller.appspotmail.com
> It will help syzbot understand when the bug is fixed. See footer for
> details.
> If you forward the report, please keep this part and the footer.
#syz dup: INFO: rcu detected stall in d_walk
> INFO: rcu_sched self-detected stall on CPU
> 1-...!: (124995 ticks this GP) idle=b86/1/4611686018427387906
> softirq=32196/32196 fqs=3
> (t=125000 jiffies g=16751 c=16750 q=347)
> rcu_sched kthread starved for 124987 jiffies! g16751 c16750 f0x0
> RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1
> RCU grace-period kthread stack dump:
> rcu_sched R running task 23544 9 2 0x80000000
> Call Trace:
> context_switch kernel/sched/core.c:2848 [inline]
> __schedule+0x801/0x1e30 kernel/sched/core.c:3490
> schedule+0xef/0x430 kernel/sched/core.c:3549
> schedule_timeout+0x138/0x240 kernel/time/timer.c:1801
> rcu_gp_kthread+0x6b5/0x1940 kernel/rcu/tree.c:2231
> kthread+0x345/0x410 kernel/kthread.c:238
> ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411
> NMI backtrace for cpu 1
> CPU: 1 PID: 4559 Comm: syz-executor6 Not tainted 4.16.0+ #2
> 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+0x1b9/0x294 lib/dump_stack.c:113
> nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
> nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62
> arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
> trigger_single_cpu_backtrace include/linux/nmi.h:156 [inline]
> rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1376
> print_cpu_stall kernel/rcu/tree.c:1525 [inline]
> check_cpu_stall.isra.61.cold.80+0x36c/0x59a kernel/rcu/tree.c:1593
> __rcu_pending kernel/rcu/tree.c:3356 [inline]
> rcu_pending kernel/rcu/tree.c:3401 [inline]
> rcu_check_callbacks+0x21b/0xad0 kernel/rcu/tree.c:2763
> update_process_times+0x2d/0x70 kernel/time/timer.c:1636
> tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:173
> tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1283
> __run_hrtimer kernel/time/hrtimer.c:1386 [inline]
> __hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1448
> hrtimer_interrupt+0x286/0x650 kernel/time/hrtimer.c:1506
> local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
> smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050
> apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:862
> </IRQ>
> RIP: 0010:__sanitizer_cov_trace_pc+0x14/0x50 kernel/kcov.c:94
> RSP: 0018:ffff88018e2e7a80 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
> RAX: ffff88018e2de680 RBX: ffff88018e2e7bf8 RCX: ffffffff81c2b1d9
> RDX: 0000000000000000 RSI: ffffffff81c26bf3 RDI: ffff88018e2e7bf8
> RBP: ffff88018e2e7a80 R08: ffff88018e2de680 R09: ffffed003b51c378
> R10: ffffed003b51c378 R11: ffff8801da8e1bc3 R12: ffff88018e2e7c30
> R13: dffffc0000000000 R14: 1ffff10031c5cf7e R15: ffffed0031c5cf81
> shrink_dentry_list+0x5a8/0x7c0 fs/dcache.c:1087
> shrink_dcache_parent+0xba/0x230 fs/dcache.c:1490
> vfs_rmdir+0x202/0x470 fs/namei.c:3850
> do_rmdir+0x523/0x610 fs/namei.c:3911
> SYSC_rmdir fs/namei.c:3929 [inline]
> SyS_rmdir+0x1a/0x20 fs/namei.c:3927
> do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
> entry_SYSCALL_64_after_hwframe+0x42/0xb7
> RIP: 0033:0x455087
> RSP: 002b:00007fff8b6b76b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000054
> RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 0000000000455087
> RDX: 0000000000000000 RSI: 00007fff8b6b9460 RDI: 00007fff8b6b9460
> RBP: 00007fff8b6b9460 R08: 0000000000000000 R09: 0000000000000001
> R10: 000000000000000a R11: 0000000000000206 R12: 0000000002768940
> R13: 0000000000000000 R14: 00000000000001ec R15: 000000000001984e
>
>
> ---
> This bug is generated by a dumb bot. It may contain errors.
> See https://goo.gl/tpsmEJ for details.
> Direct all questions to syzkaller@googlegroups.com.
>
> syzbot will keep track of this bug report.
> If you forgot to add the Reported-by tag, once the fix for this bug is
> merged
> into any tree, please reply to this email with:
> #syz fix: exact-commit-title
> To mark this as a duplicate of another syzbot report, please reply with:
> #syz dup: exact-subject-of-another-report
> If it's a one-off invalid bug report, please reply with:
> #syz invalid
> Note: if the crash happens again, it will cause creation of a new bug
> report.
> Note: all commands must start from beginning of the line in the email body.
>
> --
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2018-04-14 9:43 INFO: rcu detected stall in shrink_dentry_list syzbot
2018-04-14 9:45 ` Dmitry Vyukov
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