| Message ID | 20221127-snd-freeze-v7-2-127c582f1ca4@chromium.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | ASoC: SOF: Fix deadlock when shutdown a frozen userspace | expand |
Hi, On Wed, 30 Nov 2022, Ricardo Ribalda wrote: > During kexec(), the userspace might frozen. Therefore we cannot wait > for it to complete. [...] > --- a/sound/soc/sof/core.c > +++ b/sound/soc/sof/core.c > @@ -9,6 +9,7 @@ > // > > #include <linux/firmware.h> > +#include <linux/kexec.h> > #include <linux/module.h> > #include <sound/soc.h> > #include <sound/sof.h> > @@ -484,7 +485,8 @@ 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); > + if (!kexec_with_frozen_processes()) > + sof_unregister_clients(sdev); > > snd_sof_machine_unregister(sdev, pdata); I think the case you hit was specifically snd_card_disconnect_sync() that gets called via snd_sof_machine_unregister(), right, so you'd have to skip both sof_unregister_clients() and the machine_unregister(). Skipping ok might be an ok solution here. There's clearly a problem and we cannot just drop these calls in the general case (when we are going to S5), but in the specific case of kexec, this is probably safe. And I agree one way or another this needs to be fixed. Pierre and others what do you think? Br, Kai
diff --git a/sound/soc/sof/core.c b/sound/soc/sof/core.c index 3e6141d03770..4301f347bb90 100644 --- a/sound/soc/sof/core.c +++ b/sound/soc/sof/core.c @@ -9,6 +9,7 @@ // #include <linux/firmware.h> +#include <linux/kexec.h> #include <linux/module.h> #include <sound/soc.h> #include <sound/sof.h> @@ -484,7 +485,8 @@ 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); + if (!kexec_with_frozen_processes()) + sof_unregister_clients(sdev); snd_sof_machine_unregister(sdev, pdata);
During kexec(), the userspace might frozen. Therefore we cannot wait for it to complete. During a kexec with frozen processe do not unregister the clients. 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@vger.kernel.org Fixes: 83bfc7e793b5 ("ASoC: SOF: core: unregister clients and machine drivers in .shutdown") Signed-off-by: Ricardo Ribalda <ribalda@chromium.org> --- sound/soc/sof/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)