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Subject: Re: [PATCH] KVM: x86: fix missed SRCU usage in
 kvm_lapic_set_vapic_addr
To: Paolo Bonzini <pbonzini@redhat.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
References: <1479394547-15249-2-git-send-email-pbonzini@redhat.com>
Cc: Andrew Honig <ahonig@google.com>, stable@vger.kernel.org
From: David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <0067497c-dfdd-8740-8486-49b9a45c0f6e@redhat.com>
Date: Thu, 17 Nov 2016 18:37:59 +0100
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Am 17.11.2016 um 15:55 schrieb Paolo Bonzini:
> 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>
> Cc: stable@vger.kernel.org
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Looks good to me!

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 

David