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commit 1de1ea7efeb9e8543212210e34518b4049ccd285 upstream. Some parts of the cmma migration bitmap is already protected with the kvm->lock (e.g. the migration start). On the other hand the read of the cmma bits is not protected against a concurrent free, neither is the emulation of the ESSA instruction. Let's extend the locking to all related ioctls by using the slots lock for - kvm_s390_vm_start_migration - kvm_s390_vm_stop_migration - kvm_s390_set_cmma_bits - kvm_s390_get_cmma_bits In addition to that, we use synchronize_srcu before freeing the migration structure as all users hold kvm->srcu for read. (e.g. the ESSA handler). Reported-by: David Hildenbrand <david@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Fixes: 190df4a212a7 (KVM: s390: CMMA tracking, ESSA emulation, migration mode) Reviewed-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.