From: Janosch Frank <frankja@linux.ibm.com>
To: Igor Mammedov <imammedo@redhat.com>, linux-kernel@vger.kernel.org
Cc: borntraeger@de.ibm.com, david@redhat.com, cohuck@redhat.com,
heiko.carstens@de.ibm.com, gor@linux.ibm.com,
imbrenda@linux.ibm.com, linux-s390@vger.kernel.org,
kvm@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v2] KVM: s390: kvm_s390_vm_start_migration: check dirty_bitmap before using it as target for memset()
Date: Wed, 11 Sep 2019 10:36:38 +0200 [thread overview]
Message-ID: <19baa04d-0d77-7a80-65e2-e00b0d096811@linux.ibm.com> (raw)
In-Reply-To: <20190911075218.29153-1-imammedo@redhat.com>
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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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prev parent reply other threads:[~2019-09-11 8:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
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