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-rw-r--r--arch/x86/mm/init_64.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index bb00c4672ad6..2db3f30bed75 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1142,7 +1142,7 @@ void mark_rodata_ro(void)
unsigned long end = (unsigned long) &__end_rodata_hpage_align;
unsigned long text_end = PFN_ALIGN(&__stop___ex_table);
unsigned long rodata_end = PFN_ALIGN(&__end_rodata);
- unsigned long all_end = PFN_ALIGN(&_end);
+ unsigned long all_end;
printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
(end - start) >> 10);
@@ -1153,7 +1153,16 @@ void mark_rodata_ro(void)
/*
* The rodata/data/bss/brk section (but not the kernel text!)
* should also be not-executable.
+ *
+ * We align all_end to PMD_SIZE because the existing mapping
+ * is a full PMD. If we would align _brk_end to PAGE_SIZE we
+ * split the PMD and the reminder between _brk_end and the end
+ * of the PMD will remain mapped executable.
+ *
+ * Any PMD which was setup after the one which covers _brk_end
+ * has been zapped already via cleanup_highmem().
*/
+ all_end = roundup((unsigned long)_brk_end, PMD_SIZE);
set_memory_nx(rodata_start, (all_end - rodata_start) >> PAGE_SHIFT);
rodata_test();