Commits
Igor Mammedov committed 13a17cc0526
KVM: s390: kvm_s390_vm_start_migration: check dirty_bitmap before using it as target for memset()
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: afdad61615cc ("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>