From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755632Ab3DXOVU (ORCPT ); Wed, 24 Apr 2013 10:21:20 -0400 Received: from [220.181.13.134] ([220.181.13.134]:59923 "EHLO m13-134.163.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753859Ab3DXOVT convert rfc822-to-8bit (ORCPT ); Wed, 24 Apr 2013 10:21:19 -0400 X-Greylist: delayed 1208 seconds by postgrey-1.27 at vger.kernel.org; Wed, 24 Apr 2013 10:21:17 EDT X-Originating-IP: [182.151.54.154] Date: Wed, 24 Apr 2013 21:58:59 +0800 (CST) From: "Zhang Yi" To: linux-kernel@vger.kernel.org Cc: dvhart@linux.intel.com, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, dave.hansen@linux.intel.com, "zhang.yi20@zte.com.cn" Subject: [PATCH] futex: bugfix for futex-key conflict when futex use hugepage X-Priority: 3 X-Mailer: Coremail Webmail Server Version SP_ntes V3.5 build 20130412(21945.5326.5325) Copyright (c) 2002-2013 www.mailtech.cn 163com Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset=UTF-8 MIME-Version: 1.0 Message-ID: <7ac104d6.211db.13e3c5710c9.Coremail.wetpzy@163.com> X-CM-TRANSID: hsGowEA52EMj5XdRDdolAA--.1211W X-CM-SenderInfo: hzhw16r16rljoofrz/1tbiFhsJSVEAC8mrdAABsA X-Coremail-Antispam: 1U5529EdanIXcx71UUUUU7vcSsGvfC2KfnxnUU== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, I reworked the patch base on your advices。 For the line-wrapped bug before, I use this mailbox to send the mail . Signed-off-by: Zhang Yi Tested-by: Ma Chenggong Reviewed-by: Liu Dong Reviewed-by: Cui Yunfeng Reviewed-by: Lu Zhongjun Reviewed-by: Jiang Biao diff -uprN orig/linux3.9-rc7/include/linux/futex.h new/linux3.9-rc7/include/linux/futex.h--- orig/linux3.9-rc7/include/linux/futex.h 2013-04-15 00:45:16.000000000 +0000+++ new/linux3.9-rc7/include/linux/futex.h 2013-04-19 16:33:58.725880000 +0000@@ -19,7 +19,7 @@ handle_futex_death(u32 __user *uaddr, st  * The key type depends on whether it's a shared or private mapping.  * Don't rearrange members without looking at hash_futex().  *- * offset is aligned to a multiple of sizeof(u32) (== 4) by definition.+ * There are three cmponents in offset:  * We use the two low order bits of offset to tell what is the kind of key :  *  00 : Private process futex (PTHREAD_PROCESS_PRIVATE)  *       (no reference on an inode or mm)@@ -27,6 +27,9 @@ handle_futex_death(u32 __user *uaddr, st  * mapped on a file (reference on the underlying inode)  *  10 : Shared futex (PTHREAD_PROCESS_SHARED)  *       (but private mapping on an mm, and reference taken on it)+ * Bits 2 to (PAGE_SHIFT-1) indicates the offset of futex in its page.+ * The rest hign order bits indicates the index if the page is a+ * subpage of a compound page. */  #define FUT_OFF_INODE    1 /* We set bit 0 if key has a reference on inode */@@ -36,17 +39,17 @@ union futex_key {  struct {  unsigned long pgoff;  struct inode *inode;- int offset;+ long offset;  } shared;  struct {  unsigned long address;  struct mm_struct *mm;- int offset;+ long offset;  } private;  struct {  unsigned long word;  void *ptr;- int offset;+ long offset;  } both; }; diff -uprN orig/linux3.9-rc7/kernel/futex.c new/linux3.9-rc7/kernel/futex.c--- orig/linux3.9-rc7/kernel/futex.c 2013-04-15 00:45:16.000000000 +0000+++ new/linux3.9-rc7/kernel/futex.c 2013-04-19 16:24:05.629143000 +0000@@ -215,6 +215,22 @@ static void drop_futex_key_refs(union fu  } } +/*+* Get subpage index in compound page, for futex_key.+*/+static inline int get_page_compound_index(struct page *page)+{+ struct page *head_page;+ if (PageHead(page))+ return 0;++ head_page = compound_head(page);+ if (compound_order(head_page) >= MAX_ORDER)+ return page_to_pfn(page) - page_to_pfn(head_page);+ else+ return page - compound_head(page);+}+ /**  * get_futex_key() - Get parameters which are the keys for a futex  * @uaddr: virtual address of the futex@@ -228,7 +244,8 @@ static void drop_futex_key_refs(union fu  * The key words are stored in *key on success.  *  * For shared mappings, it's (page->index, file_inode(vma->vm_file),- * offset_within_page).  For private mappings, it's (uaddr, current->mm).+ * page_compound_index and offset_within_page).+ * For private mappings, it's (uaddr, current->mm).  * We can usually work out the index without swapping in the page.  *  * lock_page() might sleep, the caller should not hold a spinlock.@@ -239,7 +256,7 @@ get_futex_key(u32 __user *uaddr, int fsh  unsigned long address = (unsigned long)uaddr;  struct mm_struct *mm = current->mm;  struct page *page, *page_head;- int err, ro = 0;+ int err, ro = 0, comp_idx = 0;   /*  * The futex address must be "naturally" aligned.@@ -299,6 +316,7 @@ again:  * freed from under us.  */  if (page != page_head) {+ comp_idx = get_page_compound_index(page);  get_page(page_head);  put_page(page);  }@@ -311,6 +329,7 @@ again: #else  page_head = compound_head(page);  if (page != page_head) {+ comp_idx = get_page_compound_index(page);  get_page(page_head);  put_page(page);  }@@ -363,7 +382,9 @@ again:  key->private.mm = mm;  key->private.address = address;  } else {- key->both.offset |= FUT_OFF_INODE; /* inode-based key */+ /* inode-based key */+ key->both.offset |= ((long)comp_idx << PAGE_SHIFT)+   | FUT_OFF_INODE;  key->shared.inode = page_head->mapping->host;  key->shared.pgoff = page_head->index;  }