* [PATCH] KVM: nVMX: Fix reload apic access page warning
@ 2016-09-06 9:20 Wanpeng Li
2016-09-16 1:07 ` Wanpeng Li
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Wanpeng Li @ 2016-09-06 9:20 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Wanpeng Li, Paolo Bonzini, Radim Krčmář, Yunhong Jiang
From: Wanpeng Li <wanpeng.li@hotmail.com>
WARNING: CPU: 1 PID: 4230 at kernel/sched/core.c:7564 __might_sleep+0x7e/0x80
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8d0de7f9>] prepare_to_swait+0x39/0xa0
CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
Call Trace:
dump_stack+0x99/0xd0
__warn+0xd1/0xf0
warn_slowpath_fmt+0x4f/0x60
? prepare_to_swait+0x39/0xa0
? prepare_to_swait+0x39/0xa0
__might_sleep+0x7e/0x80
__gfn_to_pfn_memslot+0x156/0x480 [kvm]
gfn_to_pfn+0x2a/0x30 [kvm]
gfn_to_page+0xe/0x20 [kvm]
kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
? _raw_spin_unlock_irqrestore+0x36/0x80
vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
kvm_vcpu_check_block+0x12/0x60 [kvm]
kvm_vcpu_block+0x94/0x4c0 [kvm]
kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
===============================
[ INFO: suspicious RCU usage. ]
4.8.0-rc5+ #47 Not tainted
-------------------------------
./include/linux/kvm_host.h:535 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
1 lock held by qemu-system-x86/4230:
#0: (&vcpu->mutex){+.+.+.}, at: [<ffffffffc062975c>] vcpu_load+0x1c/0x60 [kvm]
stack backtrace:
CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
Call Trace:
dump_stack+0x99/0xd0
lockdep_rcu_suspicious+0xe7/0x120
gfn_to_memslot+0x12a/0x140 [kvm]
gfn_to_pfn+0x12/0x30 [kvm]
gfn_to_page+0xe/0x20 [kvm]
kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
? _raw_spin_unlock_irqrestore+0x36/0x80
vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
kvm_vcpu_check_block+0x12/0x60 [kvm]
kvm_vcpu_block+0x94/0x4c0 [kvm]
kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
? __fget+0xfd/0x210
? __lock_is_held+0x54/0x70
do_vfs_ioctl+0x96/0x6a0
? __fget+0x11c/0x210
? __fget+0x5/0x210
SyS_ioctl+0x79/0x90
do_syscall_64+0x81/0x220
entry_SYSCALL64_slow_path+0x25/0x25
These can be triggered by running kvm-unit-test: ./x86-run x86/vmx.flat
The nested preemption timer is based on hrtimer which is started on L2
entry, stopped on L2 exit and evaluated via the new check_nested_events
hook. The current logic adds vCPU to a simple waitqueue (TASK_INTERRUPTIBLE)
if need to yield pCPU and w/o holding srcu read lock when accesses memslots,
both can be in nested preemption timer evaluation path which results in
the warning above.
This patch fix it by leveraging request bit to async reload APIC access
page before vmentry in order to avoid to reload directly during the nested
preemption timer evaluation, it is safe since the vmcs01 is loaded and
current is nested vmexit.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
---
arch/x86/kvm/vmx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 5cede40..ee059ce 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10793,7 +10793,7 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
* We are now running in L2, mmu_notifier will force to reload the
* page's hpa for L2 vmcs. Need to reload it for L1 before entering L1.
*/
- kvm_vcpu_reload_apic_access_page(vcpu);
+ kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu);
/*
* Exiting from L2 to L1, we're now back to L1 which thinks it just
--
1.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] KVM: nVMX: Fix reload apic access page warning
2016-09-06 9:20 [PATCH] KVM: nVMX: Fix reload apic access page warning Wanpeng Li
@ 2016-09-16 1:07 ` Wanpeng Li
2016-09-20 13:24 ` Radim Krčmář
2016-09-22 23:10 ` Radim Krčmář
2 siblings, 0 replies; 5+ messages in thread
From: Wanpeng Li @ 2016-09-16 1:07 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Wanpeng Li, Paolo Bonzini, Radim Krčmář, Yunhong Jiang
Ping, :)
2016-09-06 17:20 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
> WARNING: CPU: 1 PID: 4230 at kernel/sched/core.c:7564 __might_sleep+0x7e/0x80
> do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8d0de7f9>] prepare_to_swait+0x39/0xa0
> CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
> Call Trace:
> dump_stack+0x99/0xd0
> __warn+0xd1/0xf0
> warn_slowpath_fmt+0x4f/0x60
> ? prepare_to_swait+0x39/0xa0
> ? prepare_to_swait+0x39/0xa0
> __might_sleep+0x7e/0x80
> __gfn_to_pfn_memslot+0x156/0x480 [kvm]
> gfn_to_pfn+0x2a/0x30 [kvm]
> gfn_to_page+0xe/0x20 [kvm]
> kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
> nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
> ? _raw_spin_unlock_irqrestore+0x36/0x80
> vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
> kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
> kvm_vcpu_check_block+0x12/0x60 [kvm]
> kvm_vcpu_block+0x94/0x4c0 [kvm]
> kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
> ? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
> kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
>
> ===============================
> [ INFO: suspicious RCU usage. ]
> 4.8.0-rc5+ #47 Not tainted
> -------------------------------
> ./include/linux/kvm_host.h:535 suspicious rcu_dereference_check() usage!
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 1, debug_locks = 0
> 1 lock held by qemu-system-x86/4230:
> #0: (&vcpu->mutex){+.+.+.}, at: [<ffffffffc062975c>] vcpu_load+0x1c/0x60 [kvm]
>
> stack backtrace:
> CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
> Call Trace:
> dump_stack+0x99/0xd0
> lockdep_rcu_suspicious+0xe7/0x120
> gfn_to_memslot+0x12a/0x140 [kvm]
> gfn_to_pfn+0x12/0x30 [kvm]
> gfn_to_page+0xe/0x20 [kvm]
> kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
> nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
> ? _raw_spin_unlock_irqrestore+0x36/0x80
> vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
> kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
> kvm_vcpu_check_block+0x12/0x60 [kvm]
> kvm_vcpu_block+0x94/0x4c0 [kvm]
> kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
> ? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
> kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
> ? __fget+0xfd/0x210
> ? __lock_is_held+0x54/0x70
> do_vfs_ioctl+0x96/0x6a0
> ? __fget+0x11c/0x210
> ? __fget+0x5/0x210
> SyS_ioctl+0x79/0x90
> do_syscall_64+0x81/0x220
> entry_SYSCALL64_slow_path+0x25/0x25
>
> These can be triggered by running kvm-unit-test: ./x86-run x86/vmx.flat
>
> The nested preemption timer is based on hrtimer which is started on L2
> entry, stopped on L2 exit and evaluated via the new check_nested_events
> hook. The current logic adds vCPU to a simple waitqueue (TASK_INTERRUPTIBLE)
> if need to yield pCPU and w/o holding srcu read lock when accesses memslots,
> both can be in nested preemption timer evaluation path which results in
> the warning above.
>
> This patch fix it by leveraging request bit to async reload APIC access
> page before vmentry in order to avoid to reload directly during the nested
> preemption timer evaluation, it is safe since the vmcs01 is loaded and
> current is nested vmexit.
>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: Yunhong Jiang <yunhong.jiang@intel.com>
> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
> ---
> arch/x86/kvm/vmx.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 5cede40..ee059ce 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -10793,7 +10793,7 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
> * We are now running in L2, mmu_notifier will force to reload the
> * page's hpa for L2 vmcs. Need to reload it for L1 before entering L1.
> */
> - kvm_vcpu_reload_apic_access_page(vcpu);
> + kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu);
>
> /*
> * Exiting from L2 to L1, we're now back to L1 which thinks it just
> --
> 1.9.1
>
--
Regards,
Wanpeng Li
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] KVM: nVMX: Fix reload apic access page warning
2016-09-06 9:20 [PATCH] KVM: nVMX: Fix reload apic access page warning Wanpeng Li
2016-09-16 1:07 ` Wanpeng Li
@ 2016-09-20 13:24 ` Radim Krčmář
2016-09-21 2:33 ` Wanpeng Li
2016-09-22 23:10 ` Radim Krčmář
2 siblings, 1 reply; 5+ messages in thread
From: Radim Krčmář @ 2016-09-20 13:24 UTC (permalink / raw)
To: Wanpeng Li; +Cc: linux-kernel, kvm, Wanpeng Li, Paolo Bonzini, Yunhong Jiang
2016-09-06 17:20+0800, Wanpeng Li:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
> WARNING: CPU: 1 PID: 4230 at kernel/sched/core.c:7564 __might_sleep+0x7e/0x80
> do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8d0de7f9>] prepare_to_swait+0x39/0xa0
> CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
> Call Trace:
> dump_stack+0x99/0xd0
> __warn+0xd1/0xf0
> warn_slowpath_fmt+0x4f/0x60
> ? prepare_to_swait+0x39/0xa0
> ? prepare_to_swait+0x39/0xa0
> __might_sleep+0x7e/0x80
> __gfn_to_pfn_memslot+0x156/0x480 [kvm]
> gfn_to_pfn+0x2a/0x30 [kvm]
> gfn_to_page+0xe/0x20 [kvm]
> kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
> nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
> ? _raw_spin_unlock_irqrestore+0x36/0x80
> vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
> kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
> kvm_vcpu_check_block+0x12/0x60 [kvm]
> kvm_vcpu_block+0x94/0x4c0 [kvm]
> kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
> ? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
> kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
>
> ===============================
> [ INFO: suspicious RCU usage. ]
> 4.8.0-rc5+ #47 Not tainted
> -------------------------------
> ./include/linux/kvm_host.h:535 suspicious rcu_dereference_check() usage!
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 1, debug_locks = 0
> 1 lock held by qemu-system-x86/4230:
> #0: (&vcpu->mutex){+.+.+.}, at: [<ffffffffc062975c>] vcpu_load+0x1c/0x60 [kvm]
>
> stack backtrace:
> CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
> Call Trace:
> dump_stack+0x99/0xd0
> lockdep_rcu_suspicious+0xe7/0x120
> gfn_to_memslot+0x12a/0x140 [kvm]
> gfn_to_pfn+0x12/0x30 [kvm]
> gfn_to_page+0xe/0x20 [kvm]
> kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
> nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
> ? _raw_spin_unlock_irqrestore+0x36/0x80
> vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
> kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
> kvm_vcpu_check_block+0x12/0x60 [kvm]
> kvm_vcpu_block+0x94/0x4c0 [kvm]
> kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
> ? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
> kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
> ? __fget+0xfd/0x210
> ? __lock_is_held+0x54/0x70
> do_vfs_ioctl+0x96/0x6a0
> ? __fget+0x11c/0x210
> ? __fget+0x5/0x210
> SyS_ioctl+0x79/0x90
> do_syscall_64+0x81/0x220
> entry_SYSCALL64_slow_path+0x25/0x25
>
> These can be triggered by running kvm-unit-test: ./x86-run x86/vmx.flat
>
> The nested preemption timer is based on hrtimer which is started on L2
> entry, stopped on L2 exit and evaluated via the new check_nested_events
> hook. The current logic adds vCPU to a simple waitqueue (TASK_INTERRUPTIBLE)
> if need to yield pCPU and w/o holding srcu read lock when accesses memslots,
> both can be in nested preemption timer evaluation path which results in
> the warning above.
>
> This patch fix it by leveraging request bit to async reload APIC access
> page before vmentry in order to avoid to reload directly during the nested
> preemption timer evaluation, it is safe since the vmcs01 is loaded and
> current is nested vmexit.
>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: Yunhong Jiang <yunhong.jiang@intel.com>
> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
> ---
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] KVM: nVMX: Fix reload apic access page warning
2016-09-20 13:24 ` Radim Krčmář
@ 2016-09-21 2:33 ` Wanpeng Li
0 siblings, 0 replies; 5+ messages in thread
From: Wanpeng Li @ 2016-09-21 2:33 UTC (permalink / raw)
To: Radim Krčmář
Cc: linux-kernel, kvm, Wanpeng Li, Paolo Bonzini, Yunhong Jiang
2016-09-20 21:24 GMT+08:00 Radim Krčmář <rkrcmar@redhat.com>:
> 2016-09-06 17:20+0800, Wanpeng Li:
>> From: Wanpeng Li <wanpeng.li@hotmail.com>
>> WARNING: CPU: 1 PID: 4230 at kernel/sched/core.c:7564 __might_sleep+0x7e/0x80
>> do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8d0de7f9>] prepare_to_swait+0x39/0xa0
>> CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
>> Call Trace:
>> dump_stack+0x99/0xd0
>> __warn+0xd1/0xf0
>> warn_slowpath_fmt+0x4f/0x60
>> ? prepare_to_swait+0x39/0xa0
>> ? prepare_to_swait+0x39/0xa0
>> __might_sleep+0x7e/0x80
>> __gfn_to_pfn_memslot+0x156/0x480 [kvm]
>> gfn_to_pfn+0x2a/0x30 [kvm]
>> gfn_to_page+0xe/0x20 [kvm]
>> kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
>> nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
>> ? _raw_spin_unlock_irqrestore+0x36/0x80
>> vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
>> kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
>> kvm_vcpu_check_block+0x12/0x60 [kvm]
>> kvm_vcpu_block+0x94/0x4c0 [kvm]
>> kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
>> ? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
>> kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
>>
>> ===============================
>> [ INFO: suspicious RCU usage. ]
>> 4.8.0-rc5+ #47 Not tainted
>> -------------------------------
>> ./include/linux/kvm_host.h:535 suspicious rcu_dereference_check() usage!
>>
>> other info that might help us debug this:
>>
>>
>> rcu_scheduler_active = 1, debug_locks = 0
>> 1 lock held by qemu-system-x86/4230:
>> #0: (&vcpu->mutex){+.+.+.}, at: [<ffffffffc062975c>] vcpu_load+0x1c/0x60 [kvm]
>>
>> stack backtrace:
>> CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
>> Call Trace:
>> dump_stack+0x99/0xd0
>> lockdep_rcu_suspicious+0xe7/0x120
>> gfn_to_memslot+0x12a/0x140 [kvm]
>> gfn_to_pfn+0x12/0x30 [kvm]
>> gfn_to_page+0xe/0x20 [kvm]
>> kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
>> nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
>> ? _raw_spin_unlock_irqrestore+0x36/0x80
>> vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
>> kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
>> kvm_vcpu_check_block+0x12/0x60 [kvm]
>> kvm_vcpu_block+0x94/0x4c0 [kvm]
>> kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
>> ? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
>> kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
>> ? __fget+0xfd/0x210
>> ? __lock_is_held+0x54/0x70
>> do_vfs_ioctl+0x96/0x6a0
>> ? __fget+0x11c/0x210
>> ? __fget+0x5/0x210
>> SyS_ioctl+0x79/0x90
>> do_syscall_64+0x81/0x220
>> entry_SYSCALL64_slow_path+0x25/0x25
>>
>> These can be triggered by running kvm-unit-test: ./x86-run x86/vmx.flat
>>
>> The nested preemption timer is based on hrtimer which is started on L2
>> entry, stopped on L2 exit and evaluated via the new check_nested_events
>> hook. The current logic adds vCPU to a simple waitqueue (TASK_INTERRUPTIBLE)
>> if need to yield pCPU and w/o holding srcu read lock when accesses memslots,
>> both can be in nested preemption timer evaluation path which results in
>> the warning above.
>>
>> This patch fix it by leveraging request bit to async reload APIC access
>> page before vmentry in order to avoid to reload directly during the nested
>> preemption timer evaluation, it is safe since the vmcs01 is loaded and
>> current is nested vmexit.
>>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: Radim Krčmář <rkrcmar@redhat.com>
>> Cc: Yunhong Jiang <yunhong.jiang@intel.com>
>> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
>> ---
>
> Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Thanks. :）
Regards,
Wanpeng Li
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] KVM: nVMX: Fix reload apic access page warning
2016-09-06 9:20 [PATCH] KVM: nVMX: Fix reload apic access page warning Wanpeng Li
2016-09-16 1:07 ` Wanpeng Li
2016-09-20 13:24 ` Radim Krčmář
@ 2016-09-22 23:10 ` Radim Krčmář
2 siblings, 0 replies; 5+ messages in thread
From: Radim Krčmář @ 2016-09-22 23:10 UTC (permalink / raw)
To: Wanpeng Li; +Cc: linux-kernel, kvm, Wanpeng Li, Paolo Bonzini, Yunhong Jiang
2016-09-06 17:20+0800, Wanpeng Li:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
> WARNING: CPU: 1 PID: 4230 at kernel/sched/core.c:7564 __might_sleep+0x7e/0x80
> do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8d0de7f9>] prepare_to_swait+0x39/0xa0
> CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
> Call Trace:
> dump_stack+0x99/0xd0
> __warn+0xd1/0xf0
> warn_slowpath_fmt+0x4f/0x60
> ? prepare_to_swait+0x39/0xa0
> ? prepare_to_swait+0x39/0xa0
> __might_sleep+0x7e/0x80
> __gfn_to_pfn_memslot+0x156/0x480 [kvm]
> gfn_to_pfn+0x2a/0x30 [kvm]
> gfn_to_page+0xe/0x20 [kvm]
> kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
> nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
> ? _raw_spin_unlock_irqrestore+0x36/0x80
> vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
> kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
> kvm_vcpu_check_block+0x12/0x60 [kvm]
> kvm_vcpu_block+0x94/0x4c0 [kvm]
> kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
> ? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
> kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
>
> ===============================
> [ INFO: suspicious RCU usage. ]
> 4.8.0-rc5+ #47 Not tainted
> -------------------------------
> ./include/linux/kvm_host.h:535 suspicious rcu_dereference_check() usage!
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 1, debug_locks = 0
> 1 lock held by qemu-system-x86/4230:
> #0: (&vcpu->mutex){+.+.+.}, at: [<ffffffffc062975c>] vcpu_load+0x1c/0x60 [kvm]
>
> stack backtrace:
> CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
> Call Trace:
> dump_stack+0x99/0xd0
> lockdep_rcu_suspicious+0xe7/0x120
> gfn_to_memslot+0x12a/0x140 [kvm]
> gfn_to_pfn+0x12/0x30 [kvm]
> gfn_to_page+0xe/0x20 [kvm]
> kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
> nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
> ? _raw_spin_unlock_irqrestore+0x36/0x80
> vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
> kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
> kvm_vcpu_check_block+0x12/0x60 [kvm]
> kvm_vcpu_block+0x94/0x4c0 [kvm]
> kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
> ? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
> kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
> ? __fget+0xfd/0x210
> ? __lock_is_held+0x54/0x70
> do_vfs_ioctl+0x96/0x6a0
> ? __fget+0x11c/0x210
> ? __fget+0x5/0x210
> SyS_ioctl+0x79/0x90
> do_syscall_64+0x81/0x220
> entry_SYSCALL64_slow_path+0x25/0x25
>
> These can be triggered by running kvm-unit-test: ./x86-run x86/vmx.flat
>
> The nested preemption timer is based on hrtimer which is started on L2
> entry, stopped on L2 exit and evaluated via the new check_nested_events
> hook. The current logic adds vCPU to a simple waitqueue (TASK_INTERRUPTIBLE)
> if need to yield pCPU and w/o holding srcu read lock when accesses memslots,
> both can be in nested preemption timer evaluation path which results in
> the warning above.
>
> This patch fix it by leveraging request bit to async reload APIC access
> page before vmentry in order to avoid to reload directly during the nested
> preemption timer evaluation, it is safe since the vmcs01 is loaded and
> current is nested vmexit.
>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: Yunhong Jiang <yunhong.jiang@intel.com>
> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
> ---
Applied to kvm/queue, thanks.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-09-22 23:10 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-09-06 9:20 [PATCH] KVM: nVMX: Fix reload apic access page warning Wanpeng Li
2016-09-16 1:07 ` Wanpeng Li
2016-09-20 13:24 ` Radim Krčmář
2016-09-21 2:33 ` Wanpeng Li
2016-09-22 23:10 ` Radim Krčmář
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