* [PATCH v2] KVM: s390: kvm_s390_vm_start_migration: check dirty_bitmap before using it as target for memset()
@ 2019-09-11 7:52 Igor Mammedov
2019-09-11 7:58 ` David Hildenbrand
2019-09-11 8:36 ` Janosch Frank
0 siblings, 2 replies; 3+ messages in thread
From: Igor Mammedov @ 2019-09-11 7:52 UTC (permalink / raw)
To: linux-kernel
Cc: borntraeger, david, cohuck, frankja, heiko.carstens, gor,
imbrenda, linux-s390, kvm, stable
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 -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:
- remove not true anym 'warning' clause in commit message
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
--
2.18.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] KVM: s390: kvm_s390_vm_start_migration: check dirty_bitmap before using it as target for memset()
2019-09-11 7:52 [PATCH v2] KVM: s390: kvm_s390_vm_start_migration: check dirty_bitmap before using it as target for memset() Igor Mammedov
@ 2019-09-11 7:58 ` David Hildenbrand
2019-09-11 8:36 ` Janosch Frank
1 sibling, 0 replies; 3+ messages in thread
From: David Hildenbrand @ 2019-09-11 7:58 UTC (permalink / raw)
To: Igor Mammedov, linux-kernel
Cc: borntraeger, cohuck, frankja, heiko.carstens, gor, imbrenda,
linux-s390, kvm, stable
On 11.09.19 09:52, 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
> return -ENIVAL otherwise.
s/ENIVAL/EINVAL/
I assume Christian can fix that up when applying.
>
> 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:
> - remove not true anym 'warning' clause in commit message
> 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
>
You should keep the RB's, especially when only rephrasing the commit
message ;)
Reviewed-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] KVM: s390: kvm_s390_vm_start_migration: check dirty_bitmap before using it as target for memset()
2019-09-11 7:52 [PATCH v2] KVM: s390: kvm_s390_vm_start_migration: check dirty_bitmap before using it as target for memset() Igor Mammedov
2019-09-11 7:58 ` David Hildenbrand
@ 2019-09-11 8:36 ` Janosch Frank
1 sibling, 0 replies; 3+ messages in thread
From: Janosch Frank @ 2019-09-11 8:36 UTC (permalink / raw)
To: Igor Mammedov, linux-kernel
Cc: borntraeger, david, cohuck, heiko.carstens, gor, imbrenda,
linux-s390, kvm, stable
[-- Attachment #1.1: Type: text/plain, Size: 1323 bytes --]
On 9/11/19 9:52 AM, 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
> return -ENIVAL otherwise.
Fixed that while picking and added my reviewed-by, as well as the others
you removed.
Thanks for your patch.
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2019-09-11 7:52 [PATCH v2] KVM: s390: kvm_s390_vm_start_migration: check dirty_bitmap before using it as target for memset() Igor Mammedov
2019-09-11 7:58 ` David Hildenbrand
2019-09-11 8:36 ` Janosch Frank
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