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authorMichal Hocko <mhocko@suse.com>2021-05-22 17:41:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-22 15:09:07 -1000
commitf10628d2f613195132532e0fbda439eeed8d12a2 (patch)
treef5b5629a4dbed72a7564273c643b5c5d560ad15c /mm/gup.c
parentf9f74dc218c3cfdf0b7f9a95ddae81a081bdb79d (diff)
Revert "mm/gup: check page posion status for coredump."
While reviewing [1] I came across commit d3378e86d182 ("mm/gup: check page posion status for coredump.") and noticed that this patch is broken in two ways. First it doesn't really prevent hwpoison pages from being dumped because hwpoison pages can be marked asynchornously at any time after the check. Secondly, and more importantly, the patch introduces a ref count leak because get_dump_page takes a reference on the page which is not released. It also seems that the patch was merged incorrectly because there were follow up changes not included as well as discussions on how to address the underlying problem [2] Therefore revert the original patch. Link: http://lkml.kernel.org/r/20210429122519.15183-4-david@redhat.com [1] Link: http://lkml.kernel.org/r/57ac524c-b49a-99ec-c1e4-ef5027bfb61b@redhat.com [2] Link: https://lkml.kernel.org/r/20210505135407.31590-1-mhocko@kernel.org Fixes: d3378e86d182 ("mm/gup: check page posion status for coredump.") Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Aili Yao <yaoaili@kingsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/gup.c')
-rw-r--r--mm/gup.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/mm/gup.c b/mm/gup.c
index 0697134b6a12..3ded6a5f26b2 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1593,10 +1593,6 @@ struct page *get_dump_page(unsigned long addr)
FOLL_FORCE | FOLL_DUMP | FOLL_GET);
if (locked)
mmap_read_unlock(mm);
-
- if (ret == 1 && is_page_poisoned(page))
- return NULL;
-
return (ret == 1) ? page : NULL;
}
#endif /* CONFIG_ELF_CORE */