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Fri, 26 Jul 2019 02:38:06 -0700 (PDT) Date: Fri, 26 Jul 2019 02:38:06 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000b4358f058e924c6d@google.com> Subject: INFO: rcu detected stall in vhost_worker From: syzbot To: jasowang@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mst@redhat.com, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, virtualization@lists.linux-foundation.org Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 13bf6d6a Add linux-next specific files for 20190725 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=141449f0600000 kernel config: https://syzkaller.appspot.com/x/.config?x=8ae987d803395886 dashboard link: https://syzkaller.appspot.com/bug?extid=36e93b425cd6eb54fcc1 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15112f3fa00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=131ab578600000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+36e93b425cd6eb54fcc1@syzkaller.appspotmail.com rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10500 ticks this GP) idle=a56/1/0x4000000000000002 softirq=12266/12266 fqs=5250 (t=10502 jiffies g=14905 q=12) NMI backtrace for cpu 0 CPU: 0 PID: 10848 Comm: vhost-10847 Not tainted 5.3.0-rc1-next-20190725 #52 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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:164 [inline] rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2736 [inline] rcu_sched_clock_irq.cold+0x4dd/0xc13 kernel/rcu/tree.c:2183 update_process_times+0x32/0x80 kernel/time/timer.c:1639 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 RIP: 0010:check_memory_region_inline mm/kasan/generic.c:173 [inline] RIP: 0010:check_memory_region+0x0/0x1a0 mm/kasan/generic.c:192 Code: 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 f2 be f8 00 00 00 48 89 e5 e8 df 60 90 05 5d c3 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 <48> 85 f6 0f 84 34 01 00 00 48 b8 ff ff ff ff ff 7f ff ff 55 0f b6 RSP: 0018:ffff8880a40bf950 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: ffff8880836a8220 RCX: ffffffff81599777 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880836a8220 RBP: ffff8880a40bf958 R08: 1ffff110106d5044 R09: ffffed10106d5045 R10: ffffed10106d5044 R11: ffff8880836a8223 R12: 0000000000000001 R13: 0000000000000003 R14: ffffed10106d5044 R15: 0000000000000001 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] virt_spin_lock arch/x86/include/asm/qspinlock.h:83 [inline] native_queued_spin_lock_slowpath+0xb7/0x9f0 kernel/locking/qspinlock.c:325 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:642 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:50 [inline] queued_spin_lock include/asm-generic/qspinlock.h:81 [inline] do_raw_spin_lock+0x20e/0x2e0 kernel/locking/spinlock_debug.c:113 __raw_spin_lock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_lock+0x37/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] vhost_setup_uaddr drivers/vhost/vhost.c:790 [inline] vhost_setup_vq_uaddr drivers/vhost/vhost.c:801 [inline] vhost_vq_map_prefetch drivers/vhost/vhost.c:1783 [inline] vq_meta_prefetch+0x2a0/0xcb0 drivers/vhost/vhost.c:1804 handle_rx+0x145/0x1890 drivers/vhost/net.c:1128 handle_rx_net+0x19/0x20 drivers/vhost/net.c:1270 vhost_worker+0x2af/0x4d0 drivers/vhost/vhost.c:473 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches