Bug 1959192

Summary:	Fix memfd_test failure on hugetlbfs (F_SEAL_FUTURE_WRITE fix; copy-on-write data corrupt)
Product:	Red Hat Enterprise Linux 9	Reporter:	Peter Xu <peterx>
Component:	kernel	Assignee:	Peter Xu <peterx>
kernel sub component:	Memory Management	QA Contact:	Li Wang <liwan>
Status:	CLOSED NEXTRELEASE	Docs Contact:
Severity:	unspecified
Priority:	unspecified	CC:	aarcange, ddutile, dhildenb, lcapitulino, mm-maint, peterx, xiawu
Version:	9.0
Target Milestone:	beta
Target Release:	9.0
Hardware:	Unspecified
OS:	Unspecified
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Last Closed:	2021-11-17 21:01:29 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Peter Xu 2021-05-10 21:35:45 UTC

memfd_test fails for rhel9:

# uname -r
5.12.0-1.el9.x86_64
# ./memfd_test hugetlbfs
memfd-hugetlb: CREATE
memfd-hugetlb: BASIC
memfd-hugetlb: SEAL-WRITE
memfd-hugetlb: SEAL-FUTURE-WRITE
mmap() didn't fail as expected
Aborted (core dumped)

We need to make sure we'll get below fixes into rhel9 by either rebase or backport:

https://lore.kernel.org/lkml/20210503234356.9097-1-peterx@redhat.com/

The 1st patch is less important as it fixes F_SEAL_FUTURE_WRITE which may not have a huge lot of users, however good to have.  The 2nd fix is more important as it could cause data corruption.