Merge branch 'akpm' (Andrew's fixups)

Merge random fixes from Andrew Morton.

* emailed from Andrew Morton <akpm@linux-foundation.org>: (11 patches)
  mm: correctly synchronize rss-counters at exit/exec
  btree: catch NULL value before it does harm
  btree: fix tree corruption in btree_get_prev()
  ipc: shm: restore MADV_REMOVE functionality on shared memory segments
  drivers/platform/x86/acerhdf.c: correct Boris' mail address
  c/r: prctl: drop VMA flags test on PR_SET_MM_ stack data assignment
  c/r: prctl: add ability to get clear_tid_address
  c/r: prctl: add minimal address test to PR_SET_MM
  c/r: prctl: update prctl_set_mm_exe_file() after mm->num_exe_file_vmas removal
  MAINTAINERS: whitespace fixes
  shmem: replace_page must flush_dcache and others

drivers/platform/x86/acerhdf.c

@@ -5,7 +5,7 @@
  *
  * (C) 2009 - Peter Feuerer     peter (a) piie.net
  *                              http://piie.net
- *     2009 Borislav Petkov <petkovbb@gmail.com>
+ *     2009 Borislav Petkov	bp (a) alien8.de
  *
  * Inspired by and many thanks to:
  *  o acerfand   - Rachel Greenham

fs/exec.c

@@ -819,7 +819,6 @@ static int exec_mmap(struct mm_struct *mm)
 	/* Notify parent that we're no longer interested in the old VM */
 	tsk = current;
 	old_mm = current->mm;
-	sync_mm_rss(old_mm);
 	mm_release(tsk, old_mm);
 
 	if (old_mm) {

include/linux/prctl.h

@@ -145,4 +145,6 @@
 #define PR_SET_NO_NEW_PRIVS	38
 #define PR_GET_NO_NEW_PRIVS	39
 
+#define PR_GET_TID_ADDRESS	40
+
 #endif /* _LINUX_PRCTL_H */

include/linux/sched.h

@@ -439,6 +439,7 @@ extern int get_dumpable(struct mm_struct *mm);
 					/* leave room for more dump flags */
 #define MMF_VM_MERGEABLE	16	/* KSM may merge identical pages */
 #define MMF_VM_HUGEPAGE		17	/* set when VM_HUGEPAGE is set on vma */
+#define MMF_EXE_FILE_CHANGED	18	/* see prctl_set_mm_exe_file() */
 
 #define MMF_INIT_MASK		(MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK)
 

ipc/shm.c

@@ -393,6 +393,16 @@ static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 	return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
 }
 
+static long shm_fallocate(struct file *file, int mode, loff_t offset,
+			  loff_t len)
+{
+	struct shm_file_data *sfd = shm_file_data(file);
+
+	if (!sfd->file->f_op->fallocate)
+		return -EOPNOTSUPP;
+	return sfd->file->f_op->fallocate(file, mode, offset, len);
+}
+
 static unsigned long shm_get_unmapped_area(struct file *file,
 	unsigned long addr, unsigned long len, unsigned long pgoff,
 	unsigned long flags)
@@ -410,6 +420,7 @@ static const struct file_operations shm_file_operations = {
 	.get_unmapped_area	= shm_get_unmapped_area,
 #endif
 	.llseek		= noop_llseek,
+	.fallocate	= shm_fallocate,
 };
 
 static const struct file_operations shm_file_operations_huge = {
@@ -418,6 +429,7 @@ static const struct file_operations shm_file_operations_huge = {
 	.release	= shm_release,
 	.get_unmapped_area	= shm_get_unmapped_area,
 	.llseek		= noop_llseek,
+	.fallocate	= shm_fallocate,
 };
 
 int is_file_shm_hugepages(struct file *file)

kernel/exit.c

@@ -423,6 +423,7 @@ void daemonize(const char *name, ...)
 	 * user space pages.  We don't need them, and if we didn't close them
 	 * they would be locked into memory.
 	 */
+	mm_release(current, current->mm);
 	exit_mm(current);
 	/*
 	 * We don't want to get frozen, in case system-wide hibernation
@@ -640,7 +641,6 @@ static void exit_mm(struct task_struct * tsk)
 	struct mm_struct *mm = tsk->mm;
 	struct core_state *core_state;
 
-	mm_release(tsk, mm);
 	if (!mm)
 		return;
 	/*
@@ -960,9 +960,13 @@ void do_exit(long code)
 				preempt_count());
 
 	acct_update_integrals(tsk);
-	/* sync mm's RSS info before statistics gathering */
-	if (tsk->mm)
-		sync_mm_rss(tsk->mm);
+
+	/* Set exit_code before complete_vfork_done() in mm_release() */
+	tsk->exit_code = code;
+
+	/* Release mm and sync mm's RSS info before statistics gathering */
+	mm_release(tsk, tsk->mm);
+
 	group_dead = atomic_dec_and_test(&tsk->signal->live);
 	if (group_dead) {
 		hrtimer_cancel(&tsk->signal->real_timer);
@@ -975,7 +979,6 @@ void do_exit(long code)
 		tty_audit_exit();
 	audit_free(tsk);
 
-	tsk->exit_code = code;
 	taskstats_exit(tsk, group_dead);
 
 	exit_mm(tsk);

kernel/fork.c

@@ -619,6 +619,14 @@ void mmput(struct mm_struct *mm)
 			module_put(mm->binfmt->module);
 		mmdrop(mm);
 	}
+
+	/*
+	 * Final rss-counter synchronization. After this point there must be
+	 * no pagefaults into this mm from the current context.  Otherwise
+	 * mm->rss_stat will be inconsistent.
+	 */
+	if (mm)
+		sync_mm_rss(mm);
 }
 EXPORT_SYMBOL_GPL(mmput);
 

kernel/sys.c

@@ -1786,27 +1786,13 @@ SYSCALL_DEFINE1(umask, int, mask)
 }
 
 #ifdef CONFIG_CHECKPOINT_RESTORE
-static bool vma_flags_mismatch(struct vm_area_struct *vma,
-			       unsigned long required,
-			       unsigned long banned)
-{
-	return (vma->vm_flags & required) != required ||
-		(vma->vm_flags & banned);
-}
-
 static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
 {
+	struct vm_area_struct *vma;
 	struct file *exe_file;
 	struct dentry *dentry;
 	int err;
 
-	/*
-	 * Setting new mm::exe_file is only allowed when no VM_EXECUTABLE vma's
-	 * remain. So perform a quick test first.
-	 */
-	if (mm->num_exe_file_vmas)
-		return -EBUSY;
-
 	exe_file = fget(fd);
 	if (!exe_file)
 		return -EBADF;
@@ -1827,17 +1813,30 @@ static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
 	if (err)
 		goto exit;
 
+	down_write(&mm->mmap_sem);
+
+	/*
+	 * Forbid mm->exe_file change if there are mapped other files.
+	 */
+	err = -EBUSY;
+	for (vma = mm->mmap; vma; vma = vma->vm_next) {
+		if (vma->vm_file && !path_equal(&vma->vm_file->f_path,
+						&exe_file->f_path))
+			goto exit_unlock;
+	}
+
 	/*
 	 * The symlink can be changed only once, just to disallow arbitrary
 	 * transitions malicious software might bring in. This means one
 	 * could make a snapshot over all processes running and monitor
 	 * /proc/pid/exe changes to notice unusual activity if needed.
 	 */
-	down_write(&mm->mmap_sem);
-	if (likely(!mm->exe_file))
+	err = -EPERM;
+	if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
+		goto exit_unlock;
+
 	set_mm_exe_file(mm, exe_file);
-	else
-		err = -EBUSY;
+exit_unlock:
 	up_write(&mm->mmap_sem);
 
 exit:
@@ -1862,7 +1861,7 @@ static int prctl_set_mm(int opt, unsigned long addr,
 	if (opt == PR_SET_MM_EXE_FILE)
 		return prctl_set_mm_exe_file(mm, (unsigned int)addr);
 
-	if (addr >= TASK_SIZE)
+	if (addr >= TASK_SIZE || addr < mmap_min_addr)
 		return -EINVAL;
 
 	error = -EINVAL;
@@ -1924,12 +1923,6 @@ static int prctl_set_mm(int opt, unsigned long addr,
 			error = -EFAULT;
 			goto out;
 		}
-#ifdef CONFIG_STACK_GROWSUP
-		if (vma_flags_mismatch(vma, VM_READ | VM_WRITE | VM_GROWSUP, 0))
-#else
-		if (vma_flags_mismatch(vma, VM_READ | VM_WRITE | VM_GROWSDOWN, 0))
-#endif
-			goto out;
 		if (opt == PR_SET_MM_START_STACK)
 			mm->start_stack = addr;
 		else if (opt == PR_SET_MM_ARG_START)
@@ -1981,12 +1974,22 @@ out:
 	up_read(&mm->mmap_sem);
 	return error;
 }
+
+static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
+{
+	return put_user(me->clear_child_tid, tid_addr);
+}
+
 #else /* CONFIG_CHECKPOINT_RESTORE */
 static int prctl_set_mm(int opt, unsigned long addr,
 			unsigned long arg4, unsigned long arg5)
 {
 	return -EINVAL;
 }
+static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
+{
+	return -EINVAL;
+}
 #endif
 
 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
@@ -2124,6 +2127,9 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
 				else
 					return -EINVAL;
 				break;
+		case PR_GET_TID_ADDRESS:
+			error = prctl_get_tid_address(me, (int __user **)arg2);
+			break;
 			default:
 				return -EINVAL;
 			}

lib/btree.c

@@ -319,8 +319,8 @@ void *btree_get_prev(struct btree_head *head, struct btree_geo *geo,
 
 	if (head->height == 0)
 		return NULL;
-retry:
 	longcpy(key, __key, geo->keylen);
+retry:
 	dec_key(geo, key);
 
 	node = head->node;
@@ -351,7 +351,7 @@ retry:
 	}
 miss:
 	if (retry_key) {
-		__key = retry_key;
+		longcpy(key, retry_key, geo->keylen);
 		retry_key = NULL;
 		goto retry;
 	}
@@ -509,6 +509,7 @@ retry:
 int btree_insert(struct btree_head *head, struct btree_geo *geo,
 		unsigned long *key, void *val, gfp_t gfp)
 {
+	BUG_ON(!val);
 	return btree_insert_level(head, geo, key, val, 1, gfp);
 }
 EXPORT_SYMBOL_GPL(btree_insert);

mm/shmem.c

@@ -683,10 +683,21 @@ static int shmem_unuse_inode(struct shmem_inode_info *info,
 		mutex_lock(&shmem_swaplist_mutex);
 		/*
 		 * We needed to drop mutex to make that restrictive page
-		 * allocation; but the inode might already be freed by now,
-		 * and we cannot refer to inode or mapping or info to check.
-		 * However, we do hold page lock on the PageSwapCache page,
-		 * so can check if that still has our reference remaining.
+		 * allocation, but the inode might have been freed while we
+		 * dropped it: although a racing shmem_evict_inode() cannot
+		 * complete without emptying the radix_tree, our page lock
+		 * on this swapcache page is not enough to prevent that -
+		 * free_swap_and_cache() of our swap entry will only
+		 * trylock_page(), removing swap from radix_tree whatever.
+		 *
+		 * We must not proceed to shmem_add_to_page_cache() if the
+		 * inode has been freed, but of course we cannot rely on
+		 * inode or mapping or info to check that.  However, we can
+		 * safely check if our swap entry is still in use (and here
+		 * it can't have got reused for another page): if it's still
+		 * in use, then the inode cannot have been freed yet, and we
+		 * can safely proceed (if it's no longer in use, that tells
+		 * nothing about the inode, but we don't need to unuse swap).
 		 */
 		if (!page_swapcount(*pagep))
 			error = -ENOENT;
@@ -730,9 +741,9 @@ int shmem_unuse(swp_entry_t swap, struct page *page)
 
 	/*
 	 * There's a faint possibility that swap page was replaced before
-	 * caller locked it: it will come back later with the right page.
+	 * caller locked it: caller will come back later with the right page.
 	 */
-	if (unlikely(!PageSwapCache(page)))
+	if (unlikely(!PageSwapCache(page) || page_private(page) != swap.val))
 		goto out;
 
 	/*
@@ -995,21 +1006,15 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
 	newpage = shmem_alloc_page(gfp, info, index);
 	if (!newpage)
 		return -ENOMEM;
-	VM_BUG_ON(shmem_should_replace_page(newpage, gfp));
 
-	*pagep = newpage;
 	page_cache_get(newpage);
 	copy_highpage(newpage, oldpage);
+	flush_dcache_page(newpage);
 
-	VM_BUG_ON(!PageLocked(oldpage));
 	__set_page_locked(newpage);
-	VM_BUG_ON(!PageUptodate(oldpage));
 	SetPageUptodate(newpage);
-	VM_BUG_ON(!PageSwapBacked(oldpage));
 	SetPageSwapBacked(newpage);
-	VM_BUG_ON(!swap_index);
 	set_page_private(newpage, swap_index);
-	VM_BUG_ON(!PageSwapCache(oldpage));
 	SetPageSwapCache(newpage);
 
 	/*
@@ -1019,13 +1024,24 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
 	spin_lock_irq(&swap_mapping->tree_lock);
 	error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage,
 								   newpage);
+	if (!error) {
 		__inc_zone_page_state(newpage, NR_FILE_PAGES);
 		__dec_zone_page_state(oldpage, NR_FILE_PAGES);
+	}
 	spin_unlock_irq(&swap_mapping->tree_lock);
-	BUG_ON(error);
 
+	if (unlikely(error)) {
+		/*
+		 * Is this possible?  I think not, now that our callers check
+		 * both PageSwapCache and page_private after getting page lock;
+		 * but be defensive.  Reverse old to newpage for clear and free.
+		 */
+		oldpage = newpage;
+	} else {
 		mem_cgroup_replace_page_cache(oldpage, newpage);
 		lru_cache_add_anon(newpage);
+		*pagep = newpage;
+	}
 
 	ClearPageSwapCache(oldpage);
 	set_page_private(oldpage, 0);
@@ -1033,7 +1049,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
 	unlock_page(oldpage);
 	page_cache_release(oldpage);
 	page_cache_release(oldpage);
-	return 0;
+	return error;
 }
 
 /*
@@ -1107,7 +1123,8 @@ repeat:
 
 		/* We have to do this with page locked to prevent races */
 		lock_page(page);
-		if (!PageSwapCache(page) || page->mapping) {
+		if (!PageSwapCache(page) || page_private(page) != swap.val ||
+		    page->mapping) {
 			error = -EEXIST;	/* try again */
 			goto failed;
 		}