• Paolo Bonzini's avatar
    KVM: x86: fix missed SRCU usage in kvm_lapic_set_vapic_addr · 2156e86c
    Paolo Bonzini authored
    commit 7301d6ab 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: default avatarDmitry Vyukov <dvyukov@google.com>
    Fixes: fda4e2e8
    Cc: Andrew Honig <ahonig@google.com>
    Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
    Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
    Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
    2156e86c
x86.c 192 KB