[PATCH v1 3/7] mm: rename and move page_is_poisoned()
From: David Hildenbrand <hidden>
Date: 2021-04-29 12:25:55
Also in:
linux-hyperv, linux-mm, lkml, virtualization
Subsystem:
memory management, memory management - core, memory management - gup (get user pages), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
Commit d3378e86d182 ("mm/gup: check page posion status for coredump.")
introduced page_is_poisoned(), however, v5 [1] of the patch used
"page_is_hwpoison()" and something went wrong while upstreaming. Rename the
function and move it to page-flags.h, from where it can be used in other
-- kcore -- context.
Move the comment to the place where it belongs and simplify.
[1] https://lkml.kernel.org/r/20210322193318.377c9ce9@alex-virtual-machine
Signed-off-by: David Hildenbrand <redacted>
---
include/linux/page-flags.h | 7 +++++++
mm/gup.c | 6 +++++-
mm/internal.h | 20 --------------------
3 files changed, 12 insertions(+), 21 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 04a34c08e0a6..b8c56672a588 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h@@ -694,6 +694,13 @@ PAGEFLAG_FALSE(DoubleMap) TESTSCFLAG_FALSE(DoubleMap) #endif +static inline bool is_page_hwpoison(struct page *page) +{ + if (PageHWPoison(page)) + return true; + return PageHuge(page) && PageHWPoison(compound_head(page)); +} + /* * For pages that are never mapped to userspace (and aren't PageSlab), * page_type may be used. Because it is initialised to -1, we invert the
diff --git a/mm/gup.c b/mm/gup.c
index ef7d2da9f03f..000f3303e7f2 100644
--- a/mm/gup.c
+++ b/mm/gup.c@@ -1536,7 +1536,11 @@ struct page *get_dump_page(unsigned long addr) if (locked) mmap_read_unlock(mm); - if (ret == 1 && is_page_poisoned(page)) + /* + * We might have hwpoisoned pages still mapped into user space. Don't + * read these pages when creating a coredump, access could be fatal. + */ + if (ret == 1 && is_page_hwpoison(page)) return NULL; return (ret == 1) ? page : NULL;
diff --git a/mm/internal.h b/mm/internal.h
index cb3c5e0a7799..1432feec62df 100644
--- a/mm/internal.h
+++ b/mm/internal.h@@ -97,26 +97,6 @@ static inline void set_page_refcounted(struct page *page) set_page_count(page, 1); } -/* - * When kernel touch the user page, the user page may be have been marked - * poison but still mapped in user space, if without this page, the kernel - * can guarantee the data integrity and operation success, the kernel is - * better to check the posion status and avoid touching it, be good not to - * panic, coredump for process fatal signal is a sample case matching this - * scenario. Or if kernel can't guarantee the data integrity, it's better - * not to call this function, let kernel touch the poison page and get to - * panic. - */ -static inline bool is_page_poisoned(struct page *page) -{ - if (PageHWPoison(page)) - return true; - else if (PageHuge(page) && PageHWPoison(compound_head(page))) - return true; - - return false; -} - extern unsigned long highest_memmap_pfn; /*
--
2.30.2