Drivers running .shutdown() might want to wait for userspace to complete before exiting.

If userspace is frozen and we are running kexec they will stall the computer.

Add a way for them to figure out if they should just skip waiting for userspace.

Signed-off-by: Ricardo Ribalda ribalda@chromium.org --- include/linux/kexec.h | 3 +++ kernel/kexec_core.c | 5 +++++ 2 files changed, 8 insertions(+)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 41a686996aaa..c22711e0f7b5 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -426,6 +426,8 @@ extern int kexec_load_disabled; /* flag to track if kexec reboot is in progress */ extern bool kexec_in_progress;

+bool kexec_with_frozen_processes(void); + int crash_shrink_memory(unsigned long new_size); ssize_t crash_get_memory_size(void);

@@ -507,6 +509,7 @@ static inline void __crash_kexec(struct pt_regs *regs) { } static inline void crash_kexec(struct pt_regs *regs) { } static inline int kexec_should_crash(struct task_struct *p) { return 0; } static inline int kexec_crash_loaded(void) { return 0; } +static inline bool kexec_with_frozen_processes(void) { return false; } #define kexec_in_progress false #endif /* CONFIG_KEXEC_CORE */

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index ca2743f9c634..8bc8257ee7ca 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -54,6 +54,11 @@ note_buf_t __percpu *crash_notes; /* Flag to indicate we are going to kexec a new kernel */ bool kexec_in_progress = false;

+bool kexec_with_frozen_processes(void) +{ + return kexec_in_progress && pm_freezing; +} +EXPORT_SYMBOL(kexec_with_frozen_processes);

/* Location of the reserved area for the crash kernel */ struct resource crashk_res = {

During kexec(), the userspace is frozen. Therefore we cannot wait for it to complete.

Avoid running snd_sof_machine_unregister during shutdown.

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(-)

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);