Messages in this thread Patch in this message | | | From | Willy Tarreau <> | Subject | [PATCH 3.10 028/319] KVM: x86: fix missed SRCU usage in kvm_lapic_set_vapic_addr | Date | Sun, 5 Feb 2017 20:21:06 +0100 |
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From: Paolo Bonzini <pbonzini@redhat.com>
commit 7301d6abaea926d685832f7e1f0c37dd206b01f4 upstream.
Reported by syzkaller:
[ INFO: suspicious RCU usage. ] 4.9.0-rc4+ #47 Not tainted ------------------------------- ./include/linux/kvm_host.h:536 suspicious rcu_dereference_check() usage!
stack backtrace: CPU: 1 PID: 6679 Comm: syz-executor Not tainted 4.9.0-rc4+ #47 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffff880039e2f6d0 ffffffff81c2e46b ffff88003e3a5b40 0000000000000000 0000000000000001 ffffffff83215600 ffff880039e2f700 ffffffff81334ea9 ffffc9000730b000 0000000000000004 ffff88003c4f8420 ffff88003d3f8000 Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffff81c2e46b>] dump_stack+0xb3/0x118 lib/dump_stack.c:51 [<ffffffff81334ea9>] lockdep_rcu_suspicious+0x139/0x180 kernel/locking/lockdep.c:4445 [< inline >] __kvm_memslots include/linux/kvm_host.h:534 [< inline >] kvm_memslots include/linux/kvm_host.h:541 [<ffffffff8105d6ae>] kvm_gfn_to_hva_cache_init+0xa1e/0xce0 virt/kvm/kvm_main.c:1941 [<ffffffff8112685d>] kvm_lapic_set_vapic_addr+0xed/0x140 arch/x86/kvm/lapic.c:2217
Reported-by: Dmitry Vyukov <dvyukov@google.com> Fixes: fda4e2e85589191b123d31cdc21fd33ee70f50fd Cc: Andrew Honig <ahonig@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Radim KrÄmáŠ<rkrcmar@redhat.com> Signed-off-by: Willy Tarreau <w@1wt.eu> --- arch/x86/kvm/x86.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fc68806..1072083 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3182,6 +3182,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp, }; case KVM_SET_VAPIC_ADDR: { struct kvm_vapic_addr va; + int idx; r = -EINVAL; if (!irqchip_in_kernel(vcpu->kvm)) @@ -3189,7 +3190,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r = -EFAULT; if (copy_from_user(&va, argp, sizeof va)) goto out; + idx = srcu_read_lock(&vcpu->kvm->srcu); r = kvm_lapic_set_vapic_addr(vcpu, va.vapic_addr); + srcu_read_unlock(&vcpu->kvm->srcu, idx); break; } case KVM_X86_SETUP_MCE: { -- 2.8.0.rc2.1.gbe9624a
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