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

11 files changed, 118 insertions, 69 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index dafcba7e2312..14bc7071f9df 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1077,7 +1077,7 @@ F:	drivers/media/video/s5p-fimc/
 ARM/SAMSUNG S5P SERIES Multi Format Codec (MFC) SUPPORT
 M:      Kyungmin Park <kyungmin.park@samsung.com>
 M:      Kamil Debski <k.debski@samsung.com>
-M:     Jeongtae Park <jtp.park@samsung.com>
+M:      Jeongtae Park <jtp.park@samsung.com>
 L:      linux-arm-kernel@lists.infradead.org
 L:      linux-media@vger.kernel.org
 S:      Maintained
@@ -1743,10 +1743,10 @@ F:	include/linux/can/platform/
 CAPABILITIES
 M:      Serge Hallyn <serge.hallyn@canonical.com>
 L:      linux-security-module@vger.kernel.org
-S:      Supported       
+S:      Supported
 F:      include/linux/capability.h
 F:      security/capability.c
-F:      security/commoncap.c 
+F:      security/commoncap.c
 F:      kernel/capability.c
 
 CELL BROADBAND ENGINE ARCHITECTURE
@@ -2146,11 +2146,11 @@ S:	Orphan
 F:      drivers/net/wan/pc300*
 
 CYTTSP TOUCHSCREEN DRIVER
-M:      Javier Martinez Canillas <javier@dowhile0.org>
-L:      linux-input@vger.kernel.org
-S:      Maintained
-F:      drivers/input/touchscreen/cyttsp*
-F:      include/linux/input/cyttsp.h
+M:      Javier Martinez Canillas <javier@dowhile0.org>
+L:      linux-input@vger.kernel.org
+S:      Maintained
+F:      drivers/input/touchscreen/cyttsp*
+F:      include/linux/input/cyttsp.h
 
 DAMA SLAVE for AX.25
 M:      Joerg Reuter <jreuter@yaina.de>
@@ -5185,7 +5185,7 @@ S:	Maintained
 F:      drivers/firmware/pcdp.*
 
 PCI ERROR RECOVERY
-M:     Linas Vepstas <linasvepstas@gmail.com>
+M:      Linas Vepstas <linasvepstas@gmail.com>
 L:      linux-pci@vger.kernel.org
 S:      Supported
 F:      Documentation/PCI/pci-error-recovery.txt
diff --git a/drivers/platform/x86/acerhdf.c b/drivers/platform/x86/acerhdf.c
index 639db4d0aa76..2fd9d36acd15 100644
--- a/drivers/platform/x86/acerhdf.c
+++ b/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
diff --git a/fs/exec.c b/fs/exec.c
index a79786a8d2c8..b926ed19301e 100644
--- a/fs/exec.c
+++ b/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) {
diff --git a/include/linux/prctl.h b/include/linux/prctl.h
index 711e0a30aacc..3988012255dc 100644
--- a/include/linux/prctl.h
+++ b/include/linux/prctl.h
@@ -127,8 +127,8 @@
 #define PR_SET_PTRACER 0x59616d61
 # define PR_SET_PTRACER_ANY ((unsigned long)-1)
 
-#define PR_SET_CHILD_SUBREAPER 36
-#define PR_GET_CHILD_SUBREAPER 37
+#define PR_SET_CHILD_SUBREAPER  36
+#define PR_GET_CHILD_SUBREAPER  37
 
 /*
  * If no_new_privs is set, then operations that grant new privileges (i.e.
@@ -142,7 +142,9 @@
  * asking selinux for a specific new context (e.g. with runcon) will result
  * in execve returning -EPERM.
  */
-#define PR_SET_NO_NEW_PRIVS 38
-#define PR_GET_NO_NEW_PRIVS 39
+#define PR_SET_NO_NEW_PRIVS     38
+#define PR_GET_NO_NEW_PRIVS     39
+
+#define PR_GET_TID_ADDRESS      40
 
 #endif /* _LINUX_PRCTL_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6029d8c54476..c688d4cc2e40 100644
--- a/include/linux/sched.h
+++ b/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)
 
diff --git a/ipc/shm.c b/ipc/shm.c
index 5e2cbfdab6fc..41c1285d697a 100644
--- a/ipc/shm.c
+++ b/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)
diff --git a/kernel/exit.c b/kernel/exit.c
index 34867cc5b42a..804fb6bb8161 100644
--- a/kernel/exit.c
+++ b/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);
diff --git a/kernel/fork.c b/kernel/fork.c
index ab5211b9e622..0560781c6904 100644
--- a/kernel/fork.c
+++ b/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);
 
diff --git a/kernel/sys.c b/kernel/sys.c
index 9ff89cb9657a..f0ec44dcd415 100644
--- a/kernel/sys.c
+++ b/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))
-                set_mm_exe_file(mm, exe_file);
-        else
-                err = -EBUSY;
+        err = -EPERM;
+        if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
+                goto exit_unlock;
+
+        set_mm_exe_file(mm, exe_file);
+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;
                         }
diff --git a/lib/btree.c b/lib/btree.c
index e5ec1e9c1aa5..f9a484676cb6 100644
--- a/lib/btree.c
+++ b/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);
diff --git a/mm/shmem.c b/mm/shmem.c
index 585bd220a21e..a15a466d0d1d 100644
--- a/mm/shmem.c
+++ b/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);
-        __inc_zone_page_state(newpage, NR_FILE_PAGES);
-        __dec_zone_page_state(oldpage, NR_FILE_PAGES);
+        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);
 
-        mem_cgroup_replace_page_cache(oldpage, newpage);
-        lru_cache_add_anon(newpage);
+        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;
                 }