linux-kernel - [PATCH v8 3/3] ASoC: SOF: Fix deadlock when shutdown a frozen userspace

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Message-Id: <20221127-snd-freeze-v8-3-3bc02d09f2ce@chromium.org>
Date:   Thu, 01 Dec 2022 12:08:23 +0100
From:   Ricardo Ribalda <ribalda@...omium.org>
To:     Juergen Gross <jgross@...e.com>, Mark Brown <broonie@...nel.org>,
        Chromeos Kdump <chromeos-kdump@...gle.com>,
        Daniel Baluta <daniel.baluta@....com>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Len Brown <len.brown@...el.com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Nicholas Piggin <npiggin@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Eric Biederman <ebiederm@...ssion.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Joel Fernandes <joel@...lfernandes.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Peter Ujfalusi <peter.ujfalusi@...ux.intel.com>,
        Pavel Machek <pavel@....cz>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        Kai Vehmanen <kai.vehmanen@...ux.intel.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        "K. Y. Srinivasan" <kys@...rosoft.com>,
        Ingo Molnar <mingo@...hat.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Dexuan Cui <decui@...rosoft.com>,
        Takashi Iwai <tiwai@...e.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Bard Liao <yung-chuan.liao@...ux.intel.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Wei Liu <wei.liu@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>, x86@...nel.org
Cc:     kexec@...ts.infradead.org, alsa-devel@...a-project.org,
        Ricardo Ribalda <ribalda@...omium.org>, stable@...r.kernel.org,
        sound-open-firmware@...a-project.org,
        linuxppc-dev@...ts.ozlabs.org, linux-hyperv@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
        xen-devel@...ts.xenproject.org
Subject: [PATCH v8 3/3] ASoC: SOF: Fix deadlock when shutdown a frozen userspace

If we are shutting down due to kexec and the userspace is frozen, the
system will stall forever waiting for userspace to complete.

Do not wait for the clients to complete in that case.

This fixes:

[   84.943749] Freezing user space processes ... (elapsed 0.111 seconds) done.
[  246.784446] INFO: task kexec-lite:5123 blocked for more than 122 seconds.
[  246.819035] Call Trace:
[  246.821782]  <TASK>
[  246.824186]  __schedule+0x5f9/0x1263
[  246.828231]  schedule+0x87/0xc5
[  246.831779]  snd_card_disconnect_sync+0xb5/0x127
...
[  246.889249]  snd_sof_device_shutdown+0xb4/0x150
[  246.899317]  pci_device_shutdown+0x37/0x61
[  246.903990]  device_shutdown+0x14c/0x1d6
[  246.908391]  kernel_kexec+0x45/0xb9

And:

[  246.893222] INFO: task kexec-lite:4891 blocked for more than 122 seconds.
[  246.927709] Call Trace:
[  246.930461]  <TASK>
[  246.932819]  __schedule+0x5f9/0x1263
[  246.936855]  ? fsnotify_grab_connector+0x5c/0x70
[  246.942045]  schedule+0x87/0xc5
[  246.945567]  schedule_timeout+0x49/0xf3
[  246.949877]  wait_for_completion+0x86/0xe8
[  246.954463]  snd_card_free+0x68/0x89
...
[  247.001080]  platform_device_unregister+0x12/0x35

Cc: stable@...r.kernel.org
Fixes: 83bfc7e793b5 ("ASoC: SOF: core: unregister clients and machine drivers in .shutdown")
Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
---
 sound/soc/sof/core.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/sound/soc/sof/core.c b/sound/soc/sof/core.c
index 3e6141d03770..9587b6a85103 100644
--- a/sound/soc/sof/core.c
+++ b/sound/soc/sof/core.c
@@ -9,6 +9,8 @@
 //
 
 #include <linux/firmware.h>
+#include <linux/kexec.h>
+#include <linux/freezer.h>
 #include <linux/module.h>
 #include <sound/soc.h>
 #include <sound/sof.h>
@@ -484,9 +486,10 @@ int snd_sof_device_shutdown(struct device *dev)
 	 * make sure clients and machine driver(s) are unregistered to force
 	 * all userspace devices to be closed prior to the DSP shutdown sequence
 	 */
-	sof_unregister_clients(sdev);
-
-	snd_sof_machine_unregister(sdev, pdata);
+	if (!(kexec_in_progress() && pm_freezing())) {
+		sof_unregister_clients(sdev);
+		snd_sof_machine_unregister(sdev, pdata);
+	}
 
 	if (sdev->fw_state == SOF_FW_BOOT_COMPLETE)
 		return snd_sof_shutdown(sdev);

-- 
2.39.0.rc0.267.gcb52ba06e7-goog-b4-0.11.0-dev-696ae