[PATCH 5.6 35/73] PM: hibernate: Freeze kernel threads in software_resume()

Greg Kroah-Hartman
2020-05-04T18:09:43Z

From: Dexuan Cui <decui@microsoft.com>

commit 2351f8d295ed63393190e39c2f7c1fee1a80578f upstream.

Currently the kernel threads are not frozen in software_resume(), so
between dpm_suspend_start(PMSG_QUIESCE) and resume_target_kernel(),
system_freezable_power_efficient_wq can still try to submit SCSI
commands and this can cause a panic since the low level SCSI driver
(e.g. hv_storvsc) has quiesced the SCSI adapter and can not accept
any SCSI commands: https://lkml.org/lkml/2020/4/10/47

At first I posted a fix (https://lkml.org/lkml/2020/4/21/1318) trying
to resolve the issue from hv_storvsc, but with the help of
Bart Van Assche, I realized it's better to fix software_resume(),
since this looks like a generic issue, not only pertaining to SCSI.

Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/power/hibernate.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -898,6 +898,13 @@ static int software_resume(void)
error = freeze_processes();
if (error)
goto Close_Finish;
+
+ error = freeze_kernel_threads();
+ if (error) {
+ thaw_processes();
+ goto Close_Finish;
+ }
+
error = load_image_and_restore();
thaw_processes();