From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
syzbot+619d9f40141d826b097e@syzkaller.appspotmail.com,
Takashi Iwai <tiwai@suse.de>
Subject: [PATCH 4.18 08/35] ALSA: virmidi: Fix too long output trigger loop
Date: Tue, 21 Aug 2018 08:20:34 +0200 [thread overview]
Message-ID: <20180821055020.350192028@linuxfoundation.org> (raw)
In-Reply-To: <20180821055019.954904905@linuxfoundation.org>
4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Takashi Iwai <tiwai@suse.de>
commit 50e9ffb1996a5d11ff5040a266585bad4ceeca0a upstream.
The virmidi output trigger tries to parse the all available bytes and
process sequencer events as much as possible. In a normal situation,
this is supposed to be relatively short, but a program may give a huge
buffer and it'll take a long time in a single spin lock, which may
eventually lead to a soft lockup.
This patch simply adds a workaround, a cond_resched() call in the loop
if applicable. A better solution would be to move the event processor
into a work, but let's put a duct-tape quickly at first.
Reported-and-tested-by: Dae R. Jeong <threeearcat@gmail.com>
Reported-by: syzbot+619d9f40141d826b097e@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
sound/core/seq/seq_virmidi.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/sound/core/seq/seq_virmidi.c
+++ b/sound/core/seq/seq_virmidi.c
@@ -163,6 +163,7 @@ static void snd_virmidi_output_trigger(s
int count, res;
unsigned char buf[32], *pbuf;
unsigned long flags;
+ bool check_resched = !in_atomic();
if (up) {
vmidi->trigger = 1;
@@ -200,6 +201,15 @@ static void snd_virmidi_output_trigger(s
vmidi->event.type = SNDRV_SEQ_EVENT_NONE;
}
}
+ if (!check_resched)
+ continue;
+ /* do temporary unlock & cond_resched() for avoiding
+ * CPU soft lockup, which may happen via a write from
+ * a huge rawmidi buffer
+ */
+ spin_unlock_irqrestore(&substream->runtime->lock, flags);
+ cond_resched();
+ spin_lock_irqsave(&substream->runtime->lock, flags);
}
out:
spin_unlock_irqrestore(&substream->runtime->lock, flags);
next prev parent reply other threads:[~2018-08-21 6:22 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-21 6:20 [PATCH 4.18 00/35] 4.18.4-stable review Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 01/35] l2tp: use sk_dst_check() to avoid race on sk->sk_dst_cache Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 02/35] net_sched: fix NULL pointer dereference when delete tcindex filter Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 03/35] net_sched: Fix missing res info when create new tc_index filter Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 04/35] r8169: dont use MSI-X on RTL8168g Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 05/35] ALSA: hda - Sleep for 10ms after entering D3 on Conexant codecs Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 06/35] ALSA: hda - Turn CX8200 into D3 as well upon reboot Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 07/35] ALSA: vx222: Fix invalid endian conversions Greg Kroah-Hartman
2018-08-21 6:20 ` Greg Kroah-Hartman [this message]
2018-08-21 6:20 ` [PATCH 4.18 09/35] ALSA: cs5535audio: Fix invalid endian conversion Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 10/35] ALSA: dice: fix wrong copy to rx parameters for Alesis iO26 Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 11/35] ALSA: hda: Correct Asrock B85M-ITX power_save blacklist entry Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 12/35] ALSA: memalloc: Dont exceed over the requested size Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 13/35] ALSA: vxpocket: Fix invalid endian conversions Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 14/35] ALSA: seq: Fix poll() error return Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 16/35] USB: serial: sierra: fix potential deadlock at close Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 17/35] USB: serial: pl2303: add a new device id for ATEN Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 18/35] USB: option: add support for DW5821e Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 19/35] ACPI / PM: save NVS memory for ASUS 1025C laptop Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 20/35] tty: serial: 8250: Revert NXP SC16C2552 workaround Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 21/35] serial: 8250_exar: Read INT0 from slave device, too Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 22/35] serial: 8250_dw: always set baud rate in dw8250_set_termios Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 23/35] serial: 8250_dw: Add ACPI support for uart on Broadcom SoC Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 24/35] uio: fix wrong return value from uio_mmap() Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 25/35] misc: sram: fix resource leaks in probe error path Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 26/35] Revert "uio: use request_threaded_irq instead" Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 27/35] Bluetooth: avoid killing an already killed socket Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 28/35] isdn: Disable IIOCDBGVAR Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 29/35] net: sock_diag: Fix spectre v1 gadget in __sock_diag_cmd() Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 30/35] hv/netvsc: Fix NULL dereference at single queue mode fallback Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 31/35] r8169: dont use MSI-X on RTL8106e Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 32/35] ip_vti: fix a null pointer deferrence when create vti fallback tunnel Greg Kroah-Hartman
2018-08-21 6:20 ` [PATCH 4.18 33/35] net: ethernet: mvneta: Fix napi structure mixup on armada 3700 Greg Kroah-Hartman
2018-08-21 6:21 ` [PATCH 4.18 34/35] net: mvneta: fix mvneta_config_rss " Greg Kroah-Hartman
2018-08-21 6:21 ` [PATCH 4.18 35/35] cls_matchall: fix tcf_unbind_filter missing Greg Kroah-Hartman
2018-08-21 14:59 ` [PATCH 4.18 00/35] 4.18.4-stable review Guenter Roeck
2018-08-21 20:02 ` Greg Kroah-Hartman
2018-08-21 18:03 ` Naresh Kamboju
2018-08-21 20:03 ` Greg Kroah-Hartman
2018-08-21 19:43 ` Shuah Khan
2018-08-21 20:03 ` Greg Kroah-Hartman
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