Patch "ALSA: hda: Fix cpu lockup when stopping the cmd dmas" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

ALSA: hda: Fix cpu lockup when stopping the cmd dmas

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
alsa-hda-fix-cpu-lockup-when-stopping-the-cmd-dmas.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jeeja KP <[email protected]>
Date: Wed, 10 May 2017 11:51:58 +0530
Subject: ALSA: hda: Fix cpu lockup when stopping the cmd dmas

From: Jeeja KP <[email protected]>

commit 960013762df0a214b57f2fce655422fb52bdfd2c upstream.

Using jiffies in hdac_wait_for_cmd_dmas() to determine when to time out when interrupts are off (snd_hdac_bus_stop_cmd_io()/spin_lock_irq()) causes hard lockup so unlock while waiting using jiffies.

---<-snip->---

<0>[ 1211.603046] NMI watchdog: Watchdog detected hard LOCKUP on cpu 3
<4>[ 1211.603047] Modules linked in: snd_hda_intel i915 vgem
<4>[ 1211.603053] irq event stamp: 13366
<4>[ 1211.603053] hardirqs last  enabled at (13365):
...
<4>[ 1211.603059] Call Trace:
<4>[ 1211.603059]  ? delay_tsc+0x3d/0xc0
<4>[ 1211.603059]  __delay+0xa/0x10
<4>[ 1211.603060]  __const_udelay+0x31/0x40
<4>[ 1211.603060]  snd_hdac_bus_stop_cmd_io+0x96/0xe0 [snd_hda_core]
<4>[ 1211.603060]  ? azx_dev_disconnect+0x20/0x20 [snd_hda_intel]
<4>[ 1211.603061]  snd_hdac_bus_stop_chip+0xb1/0x100 [snd_hda_core]
<4>[ 1211.603061]  azx_stop_chip+0x9/0x10 [snd_hda_codec]
<4>[ 1211.603061]  azx_suspend+0x72/0x220 [snd_hda_intel]
<4>[ 1211.603061]  pci_pm_suspend+0x71/0x140
<4>[ 1211.603062]  dpm_run_callback+0x6f/0x330
<4>[ 1211.603062]  ? pci_pm_freeze+0xe0/0xe0
<4>[ 1211.603062]  __device_suspend+0xf9/0x370
<4>[ 1211.603062]  ? dpm_watchdog_set+0x60/0x60
<4>[ 1211.603063]  async_suspend+0x1a/0x90
<4>[ 1211.603063]  async_run_entry_fn+0x34/0x160
<4>[ 1211.603063]  process_one_work+0x1f4/0x6d0
<4>[ 1211.603063]  ? process_one_work+0x16e/0x6d0
<4>[ 1211.603064]  worker_thread+0x49/0x4a0
<4>[ 1211.603064]  kthread+0x107/0x140
<4>[ 1211.603064]  ? process_one_work+0x6d0/0x6d0
<4>[ 1211.603065]  ? kthread_create_on_node+0x40/0x40
<4>[ 1211.603065]  ret_from_fork+0x2e/0x40

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100419

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

@@ -106,7 +106,11 @@ void snd_hdac_bus_stop_cmd_io(struct hda
 	/* disable ringbuffer DMAs */
 	snd_hdac_chip_writeb(bus, RIRBCTL, 0);
 	snd_hdac_chip_writeb(bus, CORBCTL, 0);
+	spin_unlock_irq(&bus->reg_lock);
+
 	hdac_wait_for_cmd_dmas(bus);
+
+	spin_lock_irq(&bus->reg_lock);
 	/* disable unsolicited responses */
 	snd_hdac_chip_updatel(bus, GCTL, AZX_GCTL_UNSOL, 0);
 	spin_unlock_irq(&bus->reg_lock);

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/alsa-hda-fix-cpu-lockup-when-stopping-the-cmd-dmas.patch