HWPOISON: Add basic support for poisoned pages in fault handler v3
- Add a new VM_FAULT_HWPOISON error code to handle_mm_fault. Right now
architectures have to explicitely enable poison page support, so
this is forward compatible to all architectures. They only need
to add it when they enable poison page support.
- Add poison page handling in swap in fault code
v2: Add missing delayacct_clear_flag (Hidehiro Kawai)
v3: Really use delayacct_clear_flag (Hidehiro Kawai)
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9a72cc7..082b68c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -685,11 +685,12 @@
#define VM_FAULT_SIGBUS 0x0002
#define VM_FAULT_MAJOR 0x0004
#define VM_FAULT_WRITE 0x0008 /* Special case for get_user_pages */
+#define VM_FAULT_HWPOISON 0x0010 /* Hit poisoned page */
#define VM_FAULT_NOPAGE 0x0100 /* ->fault installed the pte, not return page */
#define VM_FAULT_LOCKED 0x0200 /* ->fault locked the returned page */
-#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS)
+#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_HWPOISON)
/*
* Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
diff --git a/mm/memory.c b/mm/memory.c
index aede2ce..02bae2d 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1319,7 +1319,8 @@
if (ret & VM_FAULT_ERROR) {
if (ret & VM_FAULT_OOM)
return i ? i : -ENOMEM;
- else if (ret & VM_FAULT_SIGBUS)
+ if (ret &
+ (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
return i ? i : -EFAULT;
BUG();
}
@@ -2511,8 +2512,15 @@
goto out;
entry = pte_to_swp_entry(orig_pte);
- if (is_migration_entry(entry)) {
- migration_entry_wait(mm, pmd, address);
+ if (unlikely(non_swap_entry(entry))) {
+ if (is_migration_entry(entry)) {
+ migration_entry_wait(mm, pmd, address);
+ } else if (is_hwpoison_entry(entry)) {
+ ret = VM_FAULT_HWPOISON;
+ } else {
+ print_bad_pte(vma, address, orig_pte, NULL);
+ ret = VM_FAULT_OOM;
+ }
goto out;
}
delayacct_set_flag(DELAYACCT_PF_SWAPIN);
@@ -2536,6 +2544,10 @@
/* Had to read the page from swap area: Major fault */
ret = VM_FAULT_MAJOR;
count_vm_event(PGMAJFAULT);
+ } else if (PageHWPoison(page)) {
+ ret = VM_FAULT_HWPOISON;
+ delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
+ goto out;
}
lock_page(page);