Merge branch 'akpm' (incoming from Andrew Morton)

Merge misc fixes from Andrew Morton:
 "21 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (21 commits)
  mm/balloon_compaction: fix deflation when compaction is disabled
  sh: fix sh770x SCIF memory regions
  zram: avoid NULL pointer access in concurrent situation
  mm/slab_common: don't check for duplicate cache names
  ocfs2: fix d_splice_alias() return code checking
  mm: rmap: split out page_remove_file_rmap()
  mm: memcontrol: fix missed end-writeback page accounting
  mm: page-writeback: inline account_page_dirtied() into single caller
  lib/bitmap.c: fix undefined shift in __bitmap_shift_{left|right}()
  drivers/rtc/rtc-bq32k.c: fix register value
  memory-hotplug: clear pgdat which is allocated by bootmem in try_offline_node()
  drivers/rtc/rtc-s3c.c: fix initialization failure without rtc source clock
  kernel/kmod: fix use-after-free of the sub_info structure
  drivers/rtc/rtc-pm8xxx.c: rework to support pm8941 rtc
  mm, thp: fix collapsing of hugepages on madvise
  drivers: of: add return value to of_reserved_mem_device_init()
  mm: free compound page with correct order
  gcov: add ARM64 to GCOV_PROFILE_ALL
  fsnotify: next_i is freed during fsnotify_unmount_inodes.
  mm/compaction.c: avoid premature range skip in isolate_migratepages_range
  ...

1 files changed, 37 insertions, 39 deletions

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 8637e041a247..80f7a6d00519 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -196,12 +196,34 @@ int __request_module(bool wait, const char *fmt, ...)
 EXPORT_SYMBOL(__request_module);
 #endif /* CONFIG_MODULES */
 
+static void call_usermodehelper_freeinfo(struct subprocess_info *info)
+{
+	if (info->cleanup)
+		(*info->cleanup)(info);
+	kfree(info);
+}
+
+static void umh_complete(struct subprocess_info *sub_info)
+{
+	struct completion *comp = xchg(&sub_info->complete, NULL);
+	/*
+	 * See call_usermodehelper_exec(). If xchg() returns NULL
+	 * we own sub_info, the UMH_KILLABLE caller has gone away
+	 * or the caller used UMH_NO_WAIT.
+	 */
+	if (comp)
+		complete(comp);
+	else
+		call_usermodehelper_freeinfo(sub_info);
+}
+
 /*
  * This is the task which runs the usermode application
  */
 static int ____call_usermodehelper(void *data)
 {
 	struct subprocess_info *sub_info = data;
+	int wait = sub_info->wait & ~UMH_KILLABLE;
 	struct cred *new;
 	int retval;
 
@@ -221,7 +243,7 @@ static int ____call_usermodehelper(void *data)
 	retval = -ENOMEM;
 	new = prepare_kernel_cred(current);
 	if (!new)
-		goto fail;
+		goto out;
 
 	spin_lock(&umh_sysctl_lock);
 	new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset);
@@ -233,7 +255,7 @@ static int ____call_usermodehelper(void *data)
 		retval = sub_info->init(sub_info, new);
 		if (retval) {
 			abort_creds(new);
-			goto fail;
+			goto out;
 		}
 	}
 
@@ -242,12 +264,13 @@ static int ____call_usermodehelper(void *data)
 	retval = do_execve(getname_kernel(sub_info->path),
 			   (const char __user *const __user *)sub_info->argv,
 			   (const char __user *const __user *)sub_info->envp);
+out:
+	sub_info->retval = retval;
+	/* wait_for_helper() will call umh_complete if UHM_WAIT_PROC. */
+	if (wait != UMH_WAIT_PROC)
+		umh_complete(sub_info);
 	if (!retval)
 		return 0;
-
-	/* Exec failed? */
-fail:
-	sub_info->retval = retval;
 	do_exit(0);
 }
 
@@ -258,26 +281,6 @@ static int call_helper(void *data)
 	return ____call_usermodehelper(data);
 }
 
-static void call_usermodehelper_freeinfo(struct subprocess_info *info)
-{
-	if (info->cleanup)
-		(*info->cleanup)(info);
-	kfree(info);
-}
-
-static void umh_complete(struct subprocess_info *sub_info)
-{
-	struct completion *comp = xchg(&sub_info->complete, NULL);
-	/*
-	 * See call_usermodehelper_exec(). If xchg() returns NULL
-	 * we own sub_info, the UMH_KILLABLE caller has gone away.
-	 */
-	if (comp)
-		complete(comp);
-	else
-		call_usermodehelper_freeinfo(sub_info);
-}
-
 /* Keventd can't block, but this (a child) can. */
 static int wait_for_helper(void *data)
 {
@@ -336,18 +339,8 @@ static void __call_usermodehelper(struct work_struct *work)
 		kmod_thread_locker = NULL;
 	}
 
-	switch (wait) {
-	case UMH_NO_WAIT:
-		call_usermodehelper_freeinfo(sub_info);
-		break;
-
-	case UMH_WAIT_PROC:
-		if (pid > 0)
-			break;
-		/* FALLTHROUGH */
-	case UMH_WAIT_EXEC:
-		if (pid < 0)
-			sub_info->retval = pid;
+	if (pid < 0) {
+		sub_info->retval = pid;
 		umh_complete(sub_info);
 	}
 }
@@ -588,7 +581,12 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
 		goto out;
 	}
 
-	sub_info->complete = &done;
+	/*
+	 * Set the completion pointer only if there is a waiter.
+	 * This makes it possible to use umh_complete to free
+	 * the data structure in case of UMH_NO_WAIT.
+	 */
+	sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done;
 	sub_info->wait = wait;
 
 	queue_work(khelper_wq, &sub_info->work);