On 10/12/2015 19:09, Borislav Petkov wrote:
> On Thu, Dec 10, 2015 at 06:38:57PM +0100, Paolo Bonzini wrote:
>> Invoking tracepoints within kvm_guest_enter/kvm_guest_exit causes a
>> lockdep splat.
>>
>> Cc: stable@xxxxxxxxxxxxxxx
>> Reported-by: Borislav Petkov <bp@xxxxxxxxx>
>> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
>> ---
>> arch/x86/kvm/svm.c | 4 ++--
>> arch/x86/kvm/vmx.c | 3 ++-
>> arch/x86/kvm/x86.c | 2 +-
>> 3 files changed, 5 insertions(+), 4 deletions(-)
>
> Looks like you missed some...
Yeah, wait_lapic_expire also have to be moved before __kvm_guest_enter.
Paolo
> [ 144.296364] kvm: zapping shadow pages for mmio generation wraparound
> [ 164.699053] kvm: zapping shadow pages for mmio generation wraparound
> [ 312.115767] kvm: zapping shadow pages for mmio generation wraparound
> [ 432.277585] kvm: zapping shadow pages for mmio generation wraparound
>
> [ 434.547820] ===============================
> [ 434.552020] [ INFO: suspicious RCU usage. ]
> [ 434.556223] 4.4.0-rc4+ #1 Not tainted
> [ 434.559886] -------------------------------
> [ 434.564072] arch/x86/kvm/trace.h:971 suspicious rcu_dereference_check() usage!
> [ 434.571303]
> other info that might help us debug this:
>
> [ 434.579324]
> RCU used illegally from idle CPU!
> rcu_scheduler_active = 1, debug_locks = 0
> [ 434.590209] RCU used illegally from extended quiescent state!
> [ 434.595971] 1 lock held by qemu-system-x86/2402:
> [ 434.600596] #0: (&vcpu->mutex){+.+.+.}, at: [<ffffffffa020872c>] vcpu_load+0x1c/0x80 [kvm]
> [ 434.609146]
> stack backtrace:
> [ 434.613526] CPU: 4 PID: 2402 Comm: qemu-system-x86 Not tainted 4.4.0-rc4+ #1
> [ 434.620583] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A13 05/11/2014
> [ 434.627987] 0000000000000001 ffff88042f79fcf0 ffffffff813c2cfc ffff880435aa0000
> [ 434.635443] ffff88042f79fd20 ffffffff810c5157 ffff88042fd48000 0000000295a85563
> [ 434.642886] 0000000295de483f 0000000000000000 ffff88042f79fd58 ffffffffa023ec6e
> [ 434.650334] Call Trace:
> [ 434.652804] [<ffffffff813c2cfc>] dump_stack+0x4e/0x82
> [ 434.657950] [<ffffffff810c5157>] lockdep_rcu_suspicious+0xe7/0x120
> [ 434.664239] [<ffffffffa023ec6e>] wait_lapic_expire+0xfe/0x1e0 [kvm]
> [ 434.670606] [<ffffffffa022183e>] kvm_arch_vcpu_ioctl_run+0x76e/0x19c0 [kvm]
> [ 434.677674] [<ffffffffa0221982>] ? kvm_arch_vcpu_ioctl_run+0x8b2/0x19c0 [kvm]
> [ 434.684905] [<ffffffff81858acc>] ? mutex_lock_killable_nested+0x29c/0x4c0
> [ 434.691792] [<ffffffffa0208b32>] kvm_vcpu_ioctl+0x342/0x700 [kvm]
> [ 434.697984] [<ffffffff810c4a7d>] ? __lock_is_held+0x4d/0x70
> [ 434.703655] [<ffffffff812351ae>] ? __fget+0xfe/0x200
> [ 434.708719] [<ffffffff812291f1>] do_vfs_ioctl+0x301/0x550
> [ 434.714208] [<ffffffff8123531a>] ? __fget_light+0x2a/0x90
> [ 434.719700] [<ffffffff81229481>] SyS_ioctl+0x41/0x70
> [ 434.724754] [<ffffffff8185cb36>] entry_SYSCALL_64_fastpath+0x16/0x7a
> [ 437.411818] kvm [2400]: vcpu0 unhandled rdmsr: 0x606
> [ 437.416898] kvm [2400]: vcpu0 unhandled rdmsr: 0x34
>
>
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