The patch titled
Subject: mm/highmem: VM_BUG_ON() if offset + len > PAGE_SIZE
has been added to the -mm tree. Its filename is
mm-highmem-vm_bug_on-if-offset-len-page_size.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-highmem-vm_bug_on-if-offset-len-page_size.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-highmem-vm_bug_on-if-offset-len-page_size.patch
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------------------------------------------------------
From: "Fabio M. De Francesco" <fmdefrancesco@xxxxxxxxx>
Subject: mm/highmem: VM_BUG_ON() if offset + len > PAGE_SIZE
Add VM_BUG_ON() bounds checking to make sure that, if "offset + len>
PAGE_SIZE", memset() does not corrupt data in adjacent pages.
Mainly to match all the similar functions in highmem.h.
Link: https://lkml.kernel.org/r/20220426193020.8710-1-fmdefrancesco@xxxxxxxxx
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/highmem.h | 2 ++
1 file changed, 2 insertions(+)
--- a/include/linux/highmem.h~mm-highmem-vm_bug_on-if-offset-len-page_size
+++ a/include/linux/highmem.h
@@ -349,6 +349,8 @@ static inline void memcpy_to_page(struct
static inline void memzero_page(struct page *page, size_t offset, size_t len)
{
char *addr = kmap_local_page(page);
+
+ VM_BUG_ON(offset + len > PAGE_SIZE);
memset(addr + offset, 0, len);
flush_dcache_page(page);
kunmap_local(addr);
_
Patches currently in -mm which might be from fmdefrancesco@xxxxxxxxx are
mm-highmem-fix-kernel-doc-warnings-in-highmemh.patch
documentation-vm-include-kdocs-from-highmemh-into-highmemrst.patch
documentation-vm-remove-using-kmap-atomic-from-highmemrst.patch
documentation-vm-rework-temporary-virtual-mappings.patch
mm-highmem-vm_bug_on-if-offset-len-page_size.patch
