The patch titled
Subject: mm: uninitialized struct page poisoning sanity checking
has been removed from the -mm tree. Its filename was
mm-uninitialized-struct-page-poisoning-sanity-checking.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Subject: mm: uninitialized struct page poisoning sanity checking
During boot we poison struct page memory in order to ensure that no one is
accessing this memory until the struct pages are initialized in
__init_single_page().
This patch adds more scrutiny to this checking by making sure that flags
do not equal the poison pattern when they are accessed. The pattern is
all ones.
Since node id is also stored in struct page, and may be accessed quite
early, we add this enforcement into page_to_nid() function as well. Note,
this is applicable only when NODE_NOT_IN_PAGE_FLAGS=n
[pasha.tatashin@xxxxxxxxxx: v4]
Link: http://lkml.kernel.org/r/20180215165920.8570-4-pasha.tatashin@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20180213193159.14606-4-pasha.tatashin@xxxxxxxxxx
Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Bharata B Rao <bharata@xxxxxxxxxxxxxxxxxx>
Cc: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Steven Sistare <steven.sistare@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 4 +++-
include/linux/page-flags.h | 22 +++++++++++++++++-----
mm/memblock.c | 2 +-
3 files changed, 21 insertions(+), 7 deletions(-)
diff -puN include/linux/mm.h~mm-uninitialized-struct-page-poisoning-sanity-checking include/linux/mm.h
--- a/include/linux/mm.h~mm-uninitialized-struct-page-poisoning-sanity-checking
+++ a/include/linux/mm.h
@@ -903,7 +903,9 @@ extern int page_to_nid(const struct page
#else
static inline int page_to_nid(const struct page *page)
{
- return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
+ struct page *p = (struct page *)page;
+
+ return (PF_POISONED_CHECK(p)->flags >> NODES_PGSHIFT) & NODES_MASK;
}
#endif
diff -puN include/linux/page-flags.h~mm-uninitialized-struct-page-poisoning-sanity-checking include/linux/page-flags.h
--- a/include/linux/page-flags.h~mm-uninitialized-struct-page-poisoning-sanity-checking
+++ a/include/linux/page-flags.h
@@ -156,9 +156,18 @@ static __always_inline int PageCompound(
return test_bit(PG_head, &page->flags) || PageTail(page);
}
+#define PAGE_POISON_PATTERN -1l
+static inline int PagePoisoned(const struct page *page)
+{
+ return page->flags == PAGE_POISON_PATTERN;
+}
+
/*
* Page flags policies wrt compound pages
*
+ * PF_POISONED_CHECK
+ * check if this struct page poisoned/uninitialized
+ *
* PF_ANY:
* the page flag is relevant for small, head and tail pages.
*
@@ -176,17 +185,20 @@ static __always_inline int PageCompound(
* PF_NO_COMPOUND:
* the page flag is not relevant for compound pages.
*/
-#define PF_ANY(page, enforce) page
-#define PF_HEAD(page, enforce) compound_head(page)
+#define PF_POISONED_CHECK(page) ({ \
+ VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \
+ page; })
+#define PF_ANY(page, enforce) PF_POISONED_CHECK(page)
+#define PF_HEAD(page, enforce) PF_POISONED_CHECK(compound_head(page))
#define PF_ONLY_HEAD(page, enforce) ({ \
VM_BUG_ON_PGFLAGS(PageTail(page), page); \
- page;})
+ PF_POISONED_CHECK(page); })
#define PF_NO_TAIL(page, enforce) ({ \
VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
- compound_head(page);})
+ PF_POISONED_CHECK(compound_head(page)); })
#define PF_NO_COMPOUND(page, enforce) ({ \
VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
- page;})
+ PF_POISONED_CHECK(page); })
/*
* Macros to create function definitions for page flags
diff -puN mm/memblock.c~mm-uninitialized-struct-page-poisoning-sanity-checking mm/memblock.c
--- a/mm/memblock.c~mm-uninitialized-struct-page-poisoning-sanity-checking
+++ a/mm/memblock.c
@@ -1345,7 +1345,7 @@ void * __init memblock_virt_alloc_try_ni
min_addr, max_addr, nid);
#ifdef CONFIG_DEBUG_VM
if (ptr && size > 0)
- memset(ptr, 0xff, size);
+ memset(ptr, PAGE_POISON_PATTERN, size);
#endif
return ptr;
}
_
Patches currently in -mm which might be from pasha.tatashin@xxxxxxxxxx are
xen-mm-allow-deferred-page-initialization-for-xen-pv-domains.patch
sparc64-ng4-memset-32-bits-overflow.patch
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