[PATCH] 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 print a warning and return -ENIVAL otherwise.
Fixes: afdad61615cc ("KVM: s390: Fix storage attributes migration with memory slots") Signed-off-by: Igor Mammedov imammedo@redhat.com --- Cc: stable@vger.kernel.org # v4.19+
v2: - drop WARN()
arch/s390/kvm/kvm-s390.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index f329dcb3f44c..2a40cd3e40b4 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1018,6 +1018,8 @@ 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
On 10.09.19 15:02, Igor Mammedov wrote:
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 print a warning and return -ENIVAL otherwise.
Fixes: afdad61615cc ("KVM: s390: Fix storage attributes migration with memory slots") Signed-off-by: Igor Mammedov imammedo@redhat.com
Cc: stable@vger.kernel.org # v4.19+
v2:
- drop WARN()
arch/s390/kvm/kvm-s390.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index f329dcb3f44c..2a40cd3e40b4 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1018,6 +1018,8 @@ 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
We properly hold the slots lock, so the bitmap cannot change while in the loop.
Reviewed-by: David Hildenbrand david@redhat.com
On 10.09.19 15:02, Igor Mammedov wrote:
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 print a warning and return -ENIVAL otherwise.
Fixes: afdad61615cc ("KVM: s390: Fix storage attributes migration with memory slots") Signed-off-by: Igor Mammedov imammedo@redhat.com
Cc: stable@vger.kernel.org # v4.19+
Reviewed-by: Christian Borntraeger borntraeger@de.ibm.com
It also matches Documentation/virt/kvm/devices/vm.txt which already allows -EINVAL.
v2:
- drop WARN()
arch/s390/kvm/kvm-s390.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index f329dcb3f44c..2a40cd3e40b4 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1018,6 +1018,8 @@ 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
On Tue, 10 Sep 2019 09:02:15 -0400 Igor Mammedov imammedo@redhat.com wrote:
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 print a warning and return -ENIVAL otherwise.
Fixes: afdad61615cc ("KVM: s390: Fix storage attributes migration with memory slots") Signed-off-by: Igor Mammedov imammedo@redhat.com
Cc: stable@vger.kernel.org # v4.19+
v2:
- drop WARN()
arch/s390/kvm/kvm-s390.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index f329dcb3f44c..2a40cd3e40b4 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1018,6 +1018,8 @@ 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
Reviewed-by: Claudio Imbrenda imbrenda@linux.ibm.com
On Tue, 10 Sep 2019 09:02:15 -0400 Igor Mammedov imammedo@redhat.com wrote:
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 print a warning and return -ENIVAL otherwise.
Fixes: afdad61615cc ("KVM: s390: Fix storage attributes migration with memory slots") Signed-off-by: Igor Mammedov imammedo@redhat.com
Cc: stable@vger.kernel.org # v4.19+
v2:
- drop WARN()
arch/s390/kvm/kvm-s390.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index f329dcb3f44c..2a40cd3e40b4 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1018,6 +1018,8 @@ 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
Reviewed-by: Cornelia Huck cohuck@redhat.com
linux-stable-mirror@lists.linaro.org
-
Christian Borntraeger -
Claudio Imbrenda -
Cornelia Huck -
David Hildenbrand -
Heiko Carstens -
Igor Mammedov