From 7682e399485fe19622b6fd82510b1f4551e48a25 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Mon, 2 Oct 2017 14:06:43 +0200
Subject: [PATCH] ALSA: usx2y: Suppress kernel warning at page allocation failures
Git-commit: 7682e399485fe19622b6fd82510b1f4551e48a25
Patch-mainline: v4.14-rc4
References: bsc#1051510
The usx2y driver allocates the stream read/write buffers in continuous
pages depending on the stream setup, and this may spew the kernel
warning messages with a stack trace like:
WARNING: CPU: 1 PID: 1846 at mm/page_alloc.c:3883
__alloc_pages_slowpath+0x1ef2/0x2d70
Modules linked in:
CPU: 1 PID: 1846 Comm: kworker/1:2 Not tainted
....
It may confuse user as if it were any serious error, although this is
no fatal error and the driver handles the error case gracefully.
Since the driver has already some sanity check of the given size (128
and 256 pages), it can't pass any crazy value. So it's merely page
fragmentation.
This patch adds __GFP_NOWARN to each caller for suppressing such
kernel warnings. The original issue was spotted by syzkaller.
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/usb/usx2y/usb_stream.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/sound/usb/usx2y/usb_stream.c b/sound/usb/usx2y/usb_stream.c
index 4dab49080700..e229abd21652 100644
--- a/sound/usb/usx2y/usb_stream.c
+++ b/sound/usb/usx2y/usb_stream.c
@@ -191,7 +191,8 @@ struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
}
pg = get_order(read_size);
- sk->s = (void *) __get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO, pg);
+ sk->s = (void *) __get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO|
+ __GFP_NOWARN, pg);
if (!sk->s) {
snd_printk(KERN_WARNING "couldn't __get_free_pages()\n");
goto out;
@@ -211,7 +212,8 @@ struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
pg = get_order(write_size);
sk->write_page =
- (void *)__get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO, pg);
+ (void *)__get_free_pages(GFP_KERNEL|__GFP_COMP|__GFP_ZERO|
+ __GFP_NOWARN, pg);
if (!sk->write_page) {
snd_printk(KERN_WARNING "couldn't __get_free_pages()\n");
usb_stream_free(sk);
--
2.15.1