HWPOISON: Add madvise() based injector for hardware poisoned pages v4
Impact: optional, useful for debugging
Add a new madvice sub command to inject poison for some
pages in a process' address space. This is useful for
testing the poison page handling.
This patch can allow root to tie up large amounts of memory.
I got feedback from container developers and they didn't see any
problem.
v2: Use write flag for get_user_pages to make sure to always get
a fresh page
v3: Don't request write mapping (Fengguang Wu)
v4: Move MADV_* number to avoid conflict with KSM (Hugh Dickins)
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/mm/madvise.c b/mm/madvise.c
index 76eb419..8dbd38b 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -207,6 +207,32 @@
return error;
}
+#ifdef CONFIG_MEMORY_FAILURE
+/*
+ * Error injection support for memory error handling.
+ */
+static int madvise_hwpoison(unsigned long start, unsigned long end)
+{
+ int ret = 0;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ for (; start < end; start += PAGE_SIZE) {
+ struct page *p;
+ int ret = get_user_pages(current, current->mm, start, 1,
+ 0, 0, &p, NULL);
+ if (ret != 1)
+ return ret;
+ printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n",
+ page_to_pfn(p), start);
+ /* Ignore return value for now */
+ __memory_failure(page_to_pfn(p), 0, 1);
+ put_page(p);
+ }
+ return ret;
+}
+#endif
+
static long
madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
unsigned long start, unsigned long end, int behavior)
@@ -307,6 +333,10 @@
int write;
size_t len;
+#ifdef CONFIG_MEMORY_FAILURE
+ if (behavior == MADV_HWPOISON)
+ return madvise_hwpoison(start, start+len_in);
+#endif
if (!madvise_behavior_valid(behavior))
return error;