From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: [PATCH 13/22] HWPOISON: Add madvise() based injector for hardware poisoned pages v3 Date: Mon, 15 Jun 2009 10:45:33 +0800 Message-ID: <20090615031254.168416512@intel.com> References: <20090615024520.786814520@intel.com> Return-path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 486E16B0085 for ; Sun, 14 Jun 2009 23:14:29 -0400 (EDT) Content-Disposition: inline; filename=mf-inject-madvise Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: LKML , Andi Kleen , Ingo Molnar , Mel Gorman , "Wu, Fengguang" , Thomas Gleixner , "H. Peter Anvin" , Peter Zijlstra , Nick Piggin , Hugh Dickins , Andi Kleen , "riel@redhat.com" , "chris.mason@oracle.com" , "linux-mm@kvack.org" List-Id: linux-mm.kvack.org From: Andi Kleen 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. Open issues: - This patch allows root to tie up arbitary amounts of memory. Should this be disabled inside containers? - There's a small race window between getting the page and injecting. The patch drops the ref count because otherwise memory_failure complains about dangling references. In theory with a multi threaded injector one could inject poison for a process foreign page this way. Not a serious issue right now. 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) Reviewed-by: Wu Fengguang Signed-off-by: Andi Kleen --- include/asm-generic/mman-common.h | 1 mm/madvise.c | 36 ++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+) --- sound-2.6.orig/mm/madvise.c +++ sound-2.6/mm/madvise.c @@ -207,6 +207,38 @@ static long madvise_remove(struct vm_are return error; } +#ifdef CONFIG_MEMORY_FAILURE +/* + * Error injection support for memory error handling. + */ +static int madvise_hwpoison(unsigned long start, unsigned long end) +{ + /* + * RED-PEN + * This allows to tie up arbitary amounts of memory. + * Might be a good idea to disable it inside containers even for root. + */ + 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; + put_page(p); + /* + * RED-PEN page can be reused in a short window, but otherwise + * we'll have to fight with the reference count. + */ + printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n", + page_to_pfn(p), start); + memory_failure(page_to_pfn(p), 0); + } + return 0; +} +#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 +339,10 @@ SYSCALL_DEFINE3(madvise, unsigned long, 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; --- sound-2.6.orig/include/asm-generic/mman-common.h +++ sound-2.6/include/asm-generic/mman-common.h @@ -34,6 +34,7 @@ #define MADV_REMOVE 9 /* remove these pages & resources */ #define MADV_DONTFORK 10 /* don't inherit across fork */ #define MADV_DOFORK 11 /* do inherit across fork */ +#define MADV_HWPOISON 12 /* poison a page for testing */ /* compatibility flags */ #define MAP_FILE 0 -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org