On Sun, Apr 26, 2020 at 8:34 PM Bart Van Assche <bvanassche@xxxxxxx> wrote: > > On 2020-04-26 09:24, Rafael J. Wysocki wrote: > > On Friday, April 24, 2020 5:40:16 AM CEST Dexuan Cui wrote: > >> 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: Bart Van Assche <bvanassche@xxxxxxx> > >> Cc: stable@xxxxxxxxxxxxxxx > >> Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx> > >> --- > >> kernel/power/hibernate.c | 7 +++++++ > >> 1 file changed, 7 insertions(+) > >> > >> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c > >> index 86aba8706b16..30bd28d1d418 100644 > >> --- 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(); > >> Finish: > > > > Applied as a fix for 5.7-rc4, thanks! > > Hi Rafael, > > What is not clear to me is how kernel threads are thawed after > load_image_and_restore() has finished? Should a comment perhaps be added > above the freeze_kernel_threads() call that explains how > thaw_kernel_threads() is invoked after load_image_and_restore() has > finished? It isn't, because that is not necessary. thaw_processes() will thaw them along with the user space. Cheers!
