diff options
| -rw-r--r-- | Documentation/vm/hwpoison.txt | 16 | ||||
| -rw-r--r-- | include/linux/mm.h | 1 | ||||
| -rw-r--r-- | include/linux/page-flags.h | 2 | ||||
| -rw-r--r-- | mm/hwpoison-inject.c | 36 | ||||
| -rw-r--r-- | mm/memory-failure.c | 68 |
5 files changed, 114 insertions, 9 deletions
diff --git a/Documentation/vm/hwpoison.txt b/Documentation/vm/hwpoison.txt index 3ffadf8da61..f047e75acb2 100644 --- a/Documentation/vm/hwpoison.txt +++ b/Documentation/vm/hwpoison.txt @@ -98,10 +98,22 @@ madvise(MADV_POISON, ....) hwpoison-inject module through debugfs - /sys/debug/hwpoison/corrupt-pfn -Inject hwpoison fault at PFN echoed into this file +/sys/debug/hwpoison/ +corrupt-pfn + +Inject hwpoison fault at PFN echoed into this file. + +unpoison-pfn + +Software-unpoison page at PFN echoed into this file. This +way a page can be reused again. +This only works for Linux injected failures, not for real +memory failures. + +Note these injection interfaces are not stable and might change between +kernel versions Architecture specific MCE injector diff --git a/include/linux/mm.h b/include/linux/mm.h index 135e19198cd..8cdb941fc7b 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1336,6 +1336,7 @@ enum mf_flags { }; extern void memory_failure(unsigned long pfn, int trapno); extern int __memory_failure(unsigned long pfn, int trapno, int flags); +extern int unpoison_memory(unsigned long pfn); extern int sysctl_memory_failure_early_kill; extern int sysctl_memory_failure_recovery; extern void shake_page(struct page *p); diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 49e907bd067..f9df6308af9 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -275,7 +275,7 @@ PAGEFLAG_FALSE(Uncached) #ifdef CONFIG_MEMORY_FAILURE PAGEFLAG(HWPoison, hwpoison) -TESTSETFLAG(HWPoison, hwpoison) +TESTSCFLAG(HWPoison, hwpoison) #define __PG_HWPOISON (1UL << PG_hwpoison) #else PAGEFLAG_FALSE(HWPoison) diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c index e1d85137f08..6e35e563bf5 100644 --- a/mm/hwpoison-inject.c +++ b/mm/hwpoison-inject.c @@ -4,7 +4,7 @@ #include <linux/kernel.h> #include <linux/mm.h> -static struct dentry *hwpoison_dir, *corrupt_pfn; +static struct dentry *hwpoison_dir; static int hwpoison_inject(void *data, u64 val) { @@ -14,7 +14,16 @@ static int hwpoison_inject(void *data, u64 val) return __memory_failure(val, 18, 0); } +static int hwpoison_unpoison(void *data, u64 val) +{ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + return unpoison_memory(val); +} + DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n"); +DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n"); static void pfn_inject_exit(void) { @@ -24,16 +33,31 @@ static void pfn_inject_exit(void) static int pfn_inject_init(void) { + struct dentry *dentry; + hwpoison_dir = debugfs_create_dir("hwpoison", NULL); if (hwpoison_dir == NULL) return -ENOMEM; - corrupt_pfn = debugfs_create_file("corrupt-pfn", 0600, hwpoison_dir, + + /* + * Note that the below poison/unpoison interfaces do not involve + * hardware status change, hence do not require hardware support. + * They are mainly for testing hwpoison in software level. + */ + dentry = debugfs_create_file("corrupt-pfn", 0600, hwpoison_dir, NULL, &hwpoison_fops); - if (corrupt_pfn == NULL) { - pfn_inject_exit(); - return -ENOMEM; - } + if (!dentry) + goto fail; + + dentry = debugfs_create_file("unpoison-pfn", 0600, hwpoison_dir, + NULL, &unpoison_fops); + if (!dentry) + goto fail; + return 0; +fail: + pfn_inject_exit(); + return -ENOMEM; } module_init(pfn_inject_init); diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 5055b940df5..ed6e91c87a5 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -838,6 +838,16 @@ int __memory_failure(unsigned long pfn, int trapno, int flags) * and in many cases impossible, so we just avoid it here. */ lock_page_nosync(p); + + /* + * unpoison always clear PG_hwpoison inside page lock + */ + if (!PageHWPoison(p)) { + action_result(pfn, "unpoisoned", IGNORED); + res = 0; + goto out; + } + wait_on_page_writeback(p); /* @@ -893,3 +903,61 @@ void memory_failure(unsigned long pfn, int trapno) { __memory_failure(pfn, trapno, 0); } + +/** + * unpoison_memory - Unpoison a previously poisoned page + * @pfn: Page number of the to be unpoisoned page + * + * Software-unpoison a page that has been poisoned by + * memory_failure() earlier. + * + * This is only done on the software-level, so it only works + * for linux injected failures, not real hardware failures + * + * Returns 0 for success, otherwise -errno. + */ +int unpoison_memory(unsigned long pfn) +{ + struct page *page; + struct page *p; + int freeit = 0; + + if (!pfn_valid(pfn)) + return -ENXIO; + + p = pfn_to_page(pfn); + page = compound_head(p); + + if (!PageHWPoison(p)) { + pr_debug("MCE: Page was already unpoisoned %#lx\n", pfn); + return 0; + } + + if (!get_page_unless_zero(page)) { + if (TestClearPageHWPoison(p)) + atomic_long_dec(&mce_bad_pages); + pr_debug("MCE: Software-unpoisoned free page %#lx\n", pfn); + return 0; + } + + lock_page_nosync(page); + /* + * This test is racy because PG_hwpoison is set outside of page lock. + * That's acceptable because that won't trigger kernel panic. Instead, + * the PG_hwpoison page will be caught and isolated on the entrance to + * the free buddy page pool. + */ + if (TestClearPageHWPoison(p)) { + pr_debug("MCE: Software-unpoisoned page %#lx\n", pfn); + atomic_long_dec(&mce_bad_pages); + freeit = 1; + } + unlock_page(page); + + put_page(page); + if (freeit) + put_page(page); + + return 0; +} +EXPORT_SYMBOL(unpoison_memory); |