What does warning mean when upgrading CentOS?

Question

CentOS

Installed CentOS.
When updating yum update, such a footcloth appears in the stream.
Tell me what this means and how critical it is when using?
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Cleanup : nss-softokn-freebl-3.16.2.3-9.el7.x86_64 535/538
Cleanup : glibc-2.17-78.el7.x86_64 536/538
Cleanup : tzdata-2015a-1.el7.noarch 537/ 538
Cleanup : libgcc-4.8.3-9.el7.x86_64 538/538
2671 blocks
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuest_RTMemTmpFree
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuestIDCCall
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7 .x86_64/weak-updates / vboxsf.ko needs unknown
symbol
/lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown
symbol -updates/vboxsf.ko needs unknown symbol VBoxGuest_RTSemFastMutexCreate
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuest_RTSemFastMutexDestroy
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuest_RTLogRelDefaultInstance
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7 .x86_64/weak-updates / vboxsf.ko needs unknown
symbol
/lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown
symbol -updates/vboxsf.ko needs unknown
symbol
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuest_RTMemContAlloc
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7 WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko
needs unknown symbol VBoxGuest_RTSemMutexRequest
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown
symbol -updates/vboxsf.ko needs unknown symbol VBoxGuest_RTSemMutexDestroy
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuest_RTAssertMsg1Weak
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuestIDCClose
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7 .x86_64/weak-updates / vboxsf.ko needs unknown
symbol
/lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown
symbol -updates/vboxsf.ko needs unknown symbol VBoxGuest_RTSemFastMutexRequest
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuest_RTSemFastMutexRelease
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown
symbol /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko
needs unknown symbol VBoxGuest_RTSemFastMutexCreate
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown
symbol -updates/vboxsf.ko needs unknown symbol VBoxGuest_RTMemContFree
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuest_RTSemMutexRelease
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7 .x86_64/weak-updates/vboxsf.ko needs unknown symbol
VBoxGuestIDC
/lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown
symbol -updates/vboxsf.ko needs unknown symbol VBoxGuest_RTMemContAlloc
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuest_RTSemMutexRequest
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown symbol VBoxGuest_RTSemMutexCreate
depmod: WARNING: /lib/modules/3.10.0-514.10.2.el7 .x86_64/weak-updates / vboxsf.ko needs unknown
symbol
/lib/modules/3.10.0-514.10.2.el7.x86_64/weak-updates/vboxsf.ko needs unknown
symbol -updates/vboxsf.ko needs unknown
symbol
Verifying : 3:irqbalance-1.0.7-6.el7.x86_64 1/538
Verifying : binutils-2.25.1-22.base.el7.x86_64 2/538
Verifying : 32:bind-license-9.9.4-38. el7_3.2.noarch 3/538
Verifying : iptables-1.4.21-17.el7.x86_64 4/538
Verifying : elfutils-libs-0.166-2.el7.x86_64 5/538
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