#include <linux/kfifo.h>
#include <linux/ratelimit.h>
#include <linux/page-isolation.h>
+#include <linux/pagewalk.h>
#include "internal.h"
#include "ras/ras_event.h"
collect_procs_file(page, tokill, force_early);
}
+struct hwp_walk {
+ struct to_kill tk;
+ unsigned long pfn;
+ int flags;
+};
+
+static void set_to_kill(struct to_kill *tk, unsigned long addr, short shift)
+{
+ tk->addr = addr;
+ tk->size_shift = shift;
+}
+
+static int check_hwpoisoned_entry(pte_t pte, unsigned long addr, short shift,
+ unsigned long poisoned_pfn, struct to_kill *tk)
+{
+ unsigned long pfn = 0;
+
+ if (pte_present(pte)) {
+ pfn = pte_pfn(pte);
+ } else {
+ swp_entry_t swp = pte_to_swp_entry(pte);
+
+ if (is_hwpoison_entry(swp))
+ pfn = hwpoison_entry_to_pfn(swp);
+ }
+
+ if (!pfn || pfn != poisoned_pfn)
+ return 0;
+
+ set_to_kill(tk, addr, shift);
+ return 1;
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static int check_hwpoisoned_pmd_entry(pmd_t *pmdp, unsigned long addr,
+ struct hwp_walk *hwp)
+{
+ pmd_t pmd = *pmdp;
+ unsigned long pfn;
+ unsigned long hwpoison_vaddr;
+
+ if (!pmd_present(pmd))
+ return 0;
+ pfn = pmd_pfn(pmd);
+ if (pfn <= hwp->pfn && hwp->pfn < pfn + HPAGE_PMD_NR) {
+ hwpoison_vaddr = addr + ((hwp->pfn - pfn) << PAGE_SHIFT);
+ set_to_kill(&hwp->tk, hwpoison_vaddr, PAGE_SHIFT);
+ return 1;
+ }
+ return 0;
+}
+#else
+static int check_hwpoisoned_pmd_entry(pmd_t *pmdp, unsigned long addr,
+ struct hwp_walk *hwp)
+{
+ return 0;
+}
+#endif
+
+static int hwpoison_pte_range(pmd_t *pmdp, unsigned long addr,
+ unsigned long end, struct mm_walk *walk)
+{
+ struct hwp_walk *hwp = (struct hwp_walk *)walk->private;
+ int ret = 0;
+ pte_t *ptep;
+ spinlock_t *ptl;
+
+ ptl = pmd_trans_huge_lock(pmdp, walk->vma);
+ if (ptl) {
+ ret = check_hwpoisoned_pmd_entry(pmdp, addr, hwp);
+ spin_unlock(ptl);
+ goto out;
+ }
+
+ if (pmd_trans_unstable(pmdp))
+ goto out;
+
+ ptep = pte_offset_map_lock(walk->vma->vm_mm, pmdp, addr, &ptl);
+ for (; addr != end; ptep++, addr += PAGE_SIZE) {
+ ret = check_hwpoisoned_entry(*ptep, addr, PAGE_SHIFT,
+ hwp->pfn, &hwp->tk);
+ if (ret == 1)
+ break;
+ }
+ pte_unmap_unlock(ptep - 1, ptl);
+out:
+ cond_resched();
+ return ret;
+}
+
+#ifdef CONFIG_HUGETLB_PAGE
+static int hwpoison_hugetlb_range(pte_t *ptep, unsigned long hmask,
+ unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
+{
+ struct hwp_walk *hwp = (struct hwp_walk *)walk->private;
+ pte_t pte = huge_ptep_get(ptep);
+ struct hstate *h = hstate_vma(walk->vma);
+
+ return check_hwpoisoned_entry(pte, addr, huge_page_shift(h),
+ hwp->pfn, &hwp->tk);
+}
+#else
+#define hwpoison_hugetlb_range NULL
+#endif
+
+static struct mm_walk_ops hwp_walk_ops = {
+ .pmd_entry = hwpoison_pte_range,
+ .hugetlb_entry = hwpoison_hugetlb_range,
+};
+
+/*
+ * Sends SIGBUS to the current process with error info.
+ *
+ * This function is intended to handle "Action Required" MCEs on already
+ * hardware poisoned pages. They could happen, for example, when
+ * memory_failure() failed to unmap the error page at the first call, or
+ * when multiple local machine checks happened on different CPUs.
+ *
+ * MCE handler currently has no easy access to the error virtual address,
+ * so this function walks page table to find it. The returned virtual address
+ * is proper in most cases, but it could be wrong when the application
+ * process has multiple entries mapping the error page.
+ */
+static int kill_accessing_process(struct task_struct *p, unsigned long pfn,
+ int flags)
+{
+ int ret;
+ struct hwp_walk priv = {
+ .pfn = pfn,
+ };
+ priv.tk.tsk = p;
+
+ mmap_read_lock(p->mm);
+ ret = walk_page_range(p->mm, 0, TASK_SIZE, &hwp_walk_ops,
+ (void *)&priv);
+ if (ret == 1 && priv.tk.addr)
+ kill_proc(&priv.tk, pfn, flags);
+ mmap_read_unlock(p->mm);
+ return ret ? -EFAULT : -EHWPOISON;
+}
+
static const char *action_name[] = {
[MF_IGNORED] = "Ignored",
[MF_FAILED] = "Failed",
return PageLRU(page) || __PageMovable(page);
}
-/**
- * __get_hwpoison_page() - Get refcount for memory error handling:
- * @page: raw error page (hit by memory error)
- *
- * Return: return 0 if failed to grab the refcount, otherwise true (some
- * non-zero value.)
- */
static int __get_hwpoison_page(struct page *page)
{
struct page *head = compound_head(page);
return 0;
}
-/*
- * Safely get reference count of an arbitrary page.
- *
- * Returns 0 for a free page, 1 for an in-use page,
- * -EIO for a page-type we cannot handle and -EBUSY if we raced with an
- * allocation.
- * We only incremented refcount in case the page was already in-use and it
- * is a known type we can handle.
- */
static int get_any_page(struct page *p, unsigned long flags)
{
int ret = 0, pass = 0;
count_increased = true;
try_again:
- if (!count_increased && !__get_hwpoison_page(p)) {
- if (page_count(p)) {
- /* We raced with an allocation, retry. */
- if (pass++ < 3)
- goto try_again;
- ret = -EBUSY;
- } else if (!PageHuge(p) && !is_free_buddy_page(p)) {
- /* We raced with put_page, retry. */
+ if (!count_increased) {
+ ret = __get_hwpoison_page(p);
+ if (!ret) {
+ if (page_count(p)) {
+ /* We raced with an allocation, retry. */
+ if (pass++ < 3)
+ goto try_again;
+ ret = -EBUSY;
+ } else if (!PageHuge(p) && !is_free_buddy_page(p)) {
+ /* We raced with put_page, retry. */
+ if (pass++ < 3)
+ goto try_again;
+ ret = -EIO;
+ }
+ goto out;
+ } else if (ret == -EBUSY) {
+ /* We raced with freeing huge page to buddy, retry. */
if (pass++ < 3)
goto try_again;
- ret = -EIO;
+ goto out;
}
+ }
+
+ if (PageHuge(p) || HWPoisonHandlable(p)) {
+ ret = 1;
} else {
- if (PageHuge(p) || HWPoisonHandlable(p)) {
- ret = 1;
- } else {
- /*
- * A page we cannot handle. Check whether we can turn
- * it into something we can handle.
- */
- if (pass++ < 3) {
- put_page(p);
- shake_page(p, 1);
- count_increased = false;
- goto try_again;
- }
+ /*
+ * A page we cannot handle. Check whether we can turn
+ * it into something we can handle.
+ */
+ if (pass++ < 3) {
put_page(p);
- ret = -EIO;
+ shake_page(p, 1);
+ count_increased = false;
+ goto try_again;
}
+ put_page(p);
+ ret = -EIO;
}
-
+out:
return ret;
}
-static int get_hwpoison_page(struct page *p, unsigned long flags,
- enum mf_flags ctxt)
+/**
+ * get_hwpoison_page() - Get refcount for memory error handling
+ * @p: Raw error page (hit by memory error)
+ * @flags: Flags controlling behavior of error handling
+ *
+ * get_hwpoison_page() takes a page refcount of an error page to handle memory
+ * error on it, after checking that the error page is in a well-defined state
+ * (defined as a page-type we can successfully handle the memor error on it,
+ * such as LRU page and hugetlb page).
+ *
+ * Memory error handling could be triggered at any time on any type of page,
+ * so it's prone to race with typical memory management lifecycle (like
+ * allocation and free). So to avoid such races, get_hwpoison_page() takes
+ * extra care for the error page's state (as done in __get_hwpoison_page()),
+ * and has some retry logic in get_any_page().
+ *
+ * Return: 0 on failure,
+ * 1 on success for in-use pages in a well-defined state,
+ * -EIO for pages on which we can not handle memory errors,
+ * -EBUSY when get_hwpoison_page() has raced with page lifecycle
+ * operations like allocation and free.
+ */
+static int get_hwpoison_page(struct page *p, unsigned long flags)
{
int ret;
zone_pcp_disable(page_zone(p));
- if (ctxt == MF_SOFT_OFFLINE)
- ret = get_any_page(p, flags);
- else
- ret = __get_hwpoison_page(p);
+ ret = get_any_page(p, flags);
zone_pcp_enable(page_zone(p));
return ret;
if (TestSetPageHWPoison(head)) {
pr_err("Memory failure: %#lx: already hardware poisoned\n",
pfn);
- return -EHWPOISON;
+ res = -EHWPOISON;
+ if (flags & MF_ACTION_REQUIRED)
+ res = kill_accessing_process(current, page_to_pfn(head), flags);
+ return res;
}
num_poisoned_pages_inc();
- if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p, flags, 0)) {
- /*
- * Check "filter hit" and "race with other subpage."
- */
- lock_page(head);
- if (PageHWPoison(head)) {
- if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
- || (p != head && TestSetPageHWPoison(head))) {
- num_poisoned_pages_dec();
- unlock_page(head);
- return 0;
+ if (!(flags & MF_COUNT_INCREASED)) {
+ res = get_hwpoison_page(p, flags);
+ if (!res) {
+ /*
+ * Check "filter hit" and "race with other subpage."
+ */
+ lock_page(head);
+ if (PageHWPoison(head)) {
+ if ((hwpoison_filter(p) && TestClearPageHWPoison(p))
+ || (p != head && TestSetPageHWPoison(head))) {
+ num_poisoned_pages_dec();
+ unlock_page(head);
+ return 0;
+ }
}
+ unlock_page(head);
+ res = MF_FAILED;
+ if (!dissolve_free_huge_page(p) && take_page_off_buddy(p)) {
+ page_ref_inc(p);
+ res = MF_RECOVERED;
+ }
+ action_result(pfn, MF_MSG_FREE_HUGE, res);
+ return res == MF_RECOVERED ? 0 : -EBUSY;
+ } else if (res < 0) {
+ action_result(pfn, MF_MSG_UNKNOWN, MF_IGNORED);
+ return -EBUSY;
}
- unlock_page(head);
- res = MF_FAILED;
- if (!dissolve_free_huge_page(p) && take_page_off_buddy(p)) {
- page_ref_inc(p);
- res = MF_RECOVERED;
- }
- action_result(pfn, MF_MSG_FREE_HUGE, res);
- return res == MF_RECOVERED ? 0 : -EBUSY;
}
lock_page(head);
pr_err("Memory failure: %#lx: already hardware poisoned\n",
pfn);
res = -EHWPOISON;
+ if (flags & MF_ACTION_REQUIRED)
+ res = kill_accessing_process(current, pfn, flags);
goto unlock_mutex;
}
* In fact it's dangerous to directly bump up page count from 0,
* that may make page_ref_freeze()/page_ref_unfreeze() mismatch.
*/
- if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p, flags, 0)) {
- if (is_free_buddy_page(p)) {
- if (take_page_off_buddy(p)) {
- page_ref_inc(p);
- res = MF_RECOVERED;
- } else {
- /* We lost the race, try again */
- if (retry) {
- ClearPageHWPoison(p);
- num_poisoned_pages_dec();
- retry = false;
- goto try_again;
+ if (!(flags & MF_COUNT_INCREASED)) {
+ res = get_hwpoison_page(p, flags);
+ if (!res) {
+ if (is_free_buddy_page(p)) {
+ if (take_page_off_buddy(p)) {
+ page_ref_inc(p);
+ res = MF_RECOVERED;
+ } else {
+ /* We lost the race, try again */
+ if (retry) {
+ ClearPageHWPoison(p);
+ num_poisoned_pages_dec();
+ retry = false;
+ goto try_again;
+ }
+ res = MF_FAILED;
}
- res = MF_FAILED;
+ action_result(pfn, MF_MSG_BUDDY, res);
+ res = res == MF_RECOVERED ? 0 : -EBUSY;
+ } else {
+ action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED);
+ res = -EBUSY;
}
- action_result(pfn, MF_MSG_BUDDY, res);
- res = res == MF_RECOVERED ? 0 : -EBUSY;
- } else {
- action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED);
+ goto unlock_mutex;
+ } else if (res < 0) {
+ action_result(pfn, MF_MSG_UNKNOWN, MF_IGNORED);
res = -EBUSY;
+ goto unlock_mutex;
}
- goto unlock_mutex;
}
if (PageTransHuge(hpage)) {
return 0;
}
- if (!get_hwpoison_page(p, flags, 0)) {
+ if (!get_hwpoison_page(p, flags)) {
if (TestClearPageHWPoison(p))
num_poisoned_pages_dec();
unpoison_pr_info("Unpoison: Software-unpoisoned free page %#lx\n",
retry:
get_online_mems();
- ret = get_hwpoison_page(page, flags, MF_SOFT_OFFLINE);
+ ret = get_hwpoison_page(page, flags);
put_online_mems();
if (ret > 0) {
projects / linux-2.6-microblaze.git / blobdiff