Re: [PATCH v3 1/3] KVM: fix rcu usage warning inkvm_arch_vcpu_ioctl_set_sregs()

[Marcelo Tosatti]

On Wed, Jan 19, 2011 at 01:16:23PM +0800, Xiao Guangrong wrote:
> On 01/12/2011 03:39 PM, Xiao Guangrong wrote:
> > Fix:
> > 
> > [ 1001.499596] ===================================================
> > [ 1001.499599] [ INFO: suspicious rcu_dereference_check() usage. ]
> > [ 1001.499601] ---------------------------------------------------
> > [ 1001.499604] include/linux/kvm_host.h:301 invoked rcu_dereference_check() without protection!
> > 	......
> > [ 1001.499636] Pid: 6035, comm: qemu-system-x86 Not tainted 2.6.37-rc6+ #62
> > [ 1001.499638] Call Trace:
> > [ 1001.499644]  [] lockdep_rcu_dereference+0x9d/0xa5
> > [ 1001.499653]  [] gfn_to_memslot+0x8d/0xc8 [kvm]
> > [ 1001.499661]  [] gfn_to_hva+0x16/0x3f [kvm]
> > [ 1001.499669]  [] kvm_read_guest_page+0x1e/0x5e [kvm]
> > [ 1001.499681]  [] kvm_read_guest_page_mmu+0x53/0x5e [kvm]
> > [ 1001.499699]  [] load_pdptrs+0x3f/0x9c [kvm]
> > [ 1001.499705]  [] ? vmx_set_cr0+0x507/0x517 [kvm_intel]
> > [ 1001.499717]  [] kvm_arch_vcpu_ioctl_set_sregs+0x1f3/0x3c0 [kvm]
> > [ 1001.499727]  [] kvm_vcpu_ioctl+0x6a5/0xbc5 [kvm]
> > 
> > Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
> 
> Ping ...?

Applied this fix. For the make_all_cpus_request optimization, can you
show numbers with this new version? Because now there is LOCK# similarly
to the spinlock.

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