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Igor Mammedov authored
commit 13a17cc0 upstream. If userspace doesn't set KVM_MEM_LOG_DIRTY_PAGES on memslot before calling kvm_s390_vm_start_migration(), kernel will oops with: Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000000000000 TEID: 0000000000000483 Fault in home space mode while using kernel ASCE. AS:0000000002a2000b R2:00000001bff8c00b R3:00000001bff88007 S:00000001bff91000 P:000000000000003d Oops: 0004 ilc:2 [#1] SMP ... Call Trace: ([<001fffff804ec552>] kvm_s390_vm_set_attr+0x347a/0x3828 [kvm]) [<001fffff804ecfc0>] kvm_arch_vm_ioctl+0x6c0/0x1998 [kvm] [<001fffff804b67e4>] kvm_vm_ioctl+0x51c/0x11a8 [kvm] [<00000000008ba572>] do_vfs_ioctl+0x1d2/0xe58 [<00000000008bb284>] ksys_ioctl+0x8c/0xb8 [<00000000008bb2e2>] sys_ioctl+0x32/0x40 [<000000000175552c>] system_call+0x2b8/0x2d8 INFO: lockdep is turned off. Last Breaking-Event-Address: [<0000000000dbaf60>] __memset+0xc/0xa0 due to ms->dirty_bitmap being NULL, which might crash the host. Make sure that ms->dirty_bitmap is set before using it or return -EINVAL otherwise. Cc: <stable@vger.kernel.org> Fixes: afdad616 ("KVM: s390: Fix storage attributes migration with memory slots") Signed-off-by:
Igor Mammedov <imammedo@redhat.com> Link: https://lore.kernel.org/kvm/20190911075218.29153-1-imammedo@redhat.com/Reviewed-by:
David Hildenbrand <david@redhat.com> Reviewed-by:
Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by:
Claudio Imbrenda <imbrenda@linux.ibm.com> Reviewed-by:
Cornelia Huck <cohuck@redhat.com> Reviewed-by:
Janosch Frank <frankja@linux.ibm.com> Signed-off-by:
Janosch Frank <frankja@linux.ibm.com> Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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