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| author | Igor Mammedov <imammedo@redhat.com> | 2019-09-11 03:52:18 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-19 09:09:34 +0200 |
| commit | 9f8a2825918c9dbef9f18ada1e9f99017dd54ae9 (patch) | |
| tree | ba53ffdbc8047767f5d17e09a7771f02b5752ebe /arch/s390 | |
| parent | 991b3458da5642a395149a72a058c2112ab46c28 (diff) | |
| download | linux-stable-9f8a2825918c9dbef9f18ada1e9f99017dd54ae9.tar.gz linux-stable-9f8a2825918c9dbef9f18ada1e9f99017dd54ae9.tar.bz2 linux-stable-9f8a2825918c9dbef9f18ada1e9f99017dd54ae9.zip | |
KVM: s390: kvm_s390_vm_start_migration: check dirty_bitmap before using it as target for memset()
commit 13a17cc0526f08d1df9507f7484176371cd263a0 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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index fc7de27960e7..6bb4f8b97b0f 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -928,6 +928,8 @@ static int kvm_s390_vm_start_migration(struct kvm *kvm) /* mark all the pages in active slots as dirty */ for (slotnr = 0; slotnr < slots->used_slots; slotnr++) { ms = slots->memslots + slotnr; + if (!ms->dirty_bitmap) + return -EINVAL; /* * The second half of the bitmap is only used on x86, * and would be wasted otherwise, so we put it to good |