From 3c72e2d1a71628ee4669875a79df42029af96e6e Mon Sep 17 00:00:00 2001
From: David Hildenbrand <david@redhat.com>
Date: Thu, 1 Sep 2022 16:26:36 +0800
Subject: [PATCH] mm/huge_memory: remove outdated VM_WARN_ON_ONCE_PAGE from
 unmap_page()

mainline inclusion
from mainline-v5.19-rc1
commit 500539419fae0aeb27189b2d62a238a056ca6742
category: bugfix
bugzilla: 187533, https://gitee.com/openeuler/kernel/issues/I5OITX
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=500539419fae0aeb27189b2d62a238a056ca6742

--------------------------------

We can already theoretically fail to unmap (still having page_mapped()) in
case arch_unmap_one() fails, which can happen on sparc.  Failures to unmap
are handled gracefully, just as if there are other references on the
target page: freezing the refcount in split_huge_page_to_list() will fail
if still mapped and we'll simply remap.

In commit 504e070dc08f ("mm: thp: replace DEBUG_VM BUG with VM_WARN when
unmap fails for split") we already converted to VM_WARN_ON_ONCE_PAGE,
let's get rid of it completely now.

This is a preparation for making try_to_migrate() fail on anonymous pages
with GUP pins, which will make this VM_WARN_ON_ONCE_PAGE trigger more
frequently.

Link: https://lkml.kernel.org/r/20220428083441.37290-11-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
---
 mm/huge_memory.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index fdd617e8197d..e6f1903f6f63 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2379,8 +2379,6 @@ static void unmap_page(struct page *page)
 		ttu_flags |= TTU_SPLIT_FREEZE;
 
 	try_to_unmap(page, ttu_flags);
-
-	VM_WARN_ON_ONCE_PAGE(page_mapped(page), page);
 }
 
 static void remap_page(struct page *page, unsigned int nr)
-- 
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