If the user space is frozen, we cannot wait for it to complete.
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
Signed-off-by: Ricardo Ribalda <[email protected]>
---
To: Jaroslav Kysela <[email protected]>
To: Takashi Iwai <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: "Joel Fernandes (Google)" <[email protected]>
---
sound/core/init.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/sound/core/init.c b/sound/core/init.c
index 5377f94eb211..f614a2cdea3d 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -9,6 +9,7 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/file.h>
+#include <linux/freezer.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/ctype.h>
@@ -573,6 +574,11 @@ void snd_card_disconnect_sync(struct snd_card *card)
return;
}
+ if (pm_freezing) {
+ dev_err(card->dev, "Userspace is frozen, skipping sync\n");
+ return;
+ }
+
spin_lock_irq(&card->files_lock);
wait_event_lock_irq(card->remove_sleep,
list_empty(&card->files_list),
@@ -658,6 +664,13 @@ int snd_card_free(struct snd_card *card)
ret = snd_card_free_when_closed(card);
if (ret)
return ret;
+
+ /*
+ * If userspace is frozen the wait from completion will never end.
+ */
+ if (pm_freezing)
+ return 0;
+
/* wait, until all devices are ready for the free operation */
wait_for_completion(&released);
---
base-commit: 4312098baf37ee17a8350725e6e0d0e8590252d4
change-id: 20221127-snd-freeze-1ee143228326
Best regards,
--
Ricardo Ribalda <[email protected]>
Hi Ricardo,
I love your patch! Yet something to improve:
[auto build test ERROR on 4312098baf37ee17a8350725e6e0d0e8590252d4]
url: https://github.com/intel-lab-lkp/linux/commits/Ricardo-Ribalda/ALSA-core-Fix-deadlock-when-shutdown-a-frozen-userspace/20221128-063051
base: 4312098baf37ee17a8350725e6e0d0e8590252d4
patch link: https://lore.kernel.org/r/20221127-snd-freeze-v1-0-57461a366ec2%40chromium.org
patch subject: [PATCH] ALSA: core: Fix deadlock when shutdown a frozen userspace
config: openrisc-randconfig-r003-20221128
compiler: or1k-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/1db83cb7b8d5d82de1492f028c45f47a83cd2b67
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Ricardo-Ribalda/ALSA-core-Fix-deadlock-when-shutdown-a-frozen-userspace/20221128-063051
git checkout 1db83cb7b8d5d82de1492f028c45f47a83cd2b67
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=openrisc SHELL=/bin/bash sound/core/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
sound/core/init.c: In function 'snd_card_disconnect_sync':
>> sound/core/init.c:577:13: error: 'pm_freezing' undeclared (first use in this function); did you mean 'freezing'?
577 | if (pm_freezing) {
| ^~~~~~~~~~~
| freezing
sound/core/init.c:577:13: note: each undeclared identifier is reported only once for each function it appears in
sound/core/init.c: In function 'snd_card_free':
sound/core/init.c:671:13: error: 'pm_freezing' undeclared (first use in this function); did you mean 'freezing'?
671 | if (pm_freezing)
| ^~~~~~~~~~~
| freezing
vim +577 sound/core/init.c
555
556 /**
557 * snd_card_disconnect_sync - disconnect card and wait until files get closed
558 * @card: card object to disconnect
559 *
560 * This calls snd_card_disconnect() for disconnecting all belonging components
561 * and waits until all pending files get closed.
562 * It assures that all accesses from user-space finished so that the driver
563 * can release its resources gracefully.
564 */
565 void snd_card_disconnect_sync(struct snd_card *card)
566 {
567 int err;
568
569 err = snd_card_disconnect(card);
570 if (err < 0) {
571 dev_err(card->dev,
572 "snd_card_disconnect error (%d), skipping sync\n",
573 err);
574 return;
575 }
576
> 577 if (pm_freezing) {
578 dev_err(card->dev, "Userspace is frozen, skipping sync\n");
579 return;
580 }
581
582 spin_lock_irq(&card->files_lock);
583 wait_event_lock_irq(card->remove_sleep,
584 list_empty(&card->files_list),
585 card->files_lock);
586 spin_unlock_irq(&card->files_lock);
587 }
588 EXPORT_SYMBOL_GPL(snd_card_disconnect_sync);
589
--
0-DAY CI Kernel Test Service
https://01.org/lkp