linux-kernel - [PATCH 4.4 099/138] ALSA: hda: Fix krealloc() with __GFP

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Date:	Thu, 18 Aug 2016 15:58:29 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Joe Perches <joe@...ches.com>,
	Takashi Iwai <tiwai@...e.de>
Subject: [PATCH 4.4 099/138] ALSA: hda: Fix krealloc() with __GFP_ZERO usage

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@...e.de>

commit 33baefe5e72f17a6df378e48196cd8cada11deec upstream.

krealloc() doesn't work always properly with __GFP_ZERO flag as
expected.  For clearing the reallocated area, we need to clear
explicitly instead.

Reported-by: Joe Perches <joe@...ches.com>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 sound/hda/array.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/sound/hda/array.c
+++ b/sound/hda/array.c
@@ -21,13 +21,15 @@ void *snd_array_new(struct snd_array *ar
 		return NULL;
 	if (array->used >= array->alloced) {
 		int num = array->alloced + array->alloc_align;
+		int oldsize = array->alloced * array->elem_size;
 		int size = (num + 1) * array->elem_size;
 		void *nlist;
 		if (snd_BUG_ON(num >= 4096))
 			return NULL;
-		nlist = krealloc(array->list, size, GFP_KERNEL | __GFP_ZERO);
+		nlist = krealloc(array->list, size, GFP_KERNEL);
 		if (!nlist)
 			return NULL;
+		memset(nlist + oldsize, 0, size - oldsize);
 		array->list = nlist;
 		array->alloced = num;
 	}