| Message ID | 20220323012103.2537-1-niedzejkob@invisiblethingslab.com |
|---|---|
| State | Accepted |
| Commit | ff32baa1f39b1adb519479a51e7acbcbfdd2206c |
| Headers | show |
| Series | xen: don't hang when resuming PCI device | expand |
On 23.03.22 02:21, Jakub Kądziołka wrote: > If a xen domain with at least two VCPUs has a PCI device attached which > enters the D3hot state during suspend, the kernel may hang while > resuming, depending on the core on which an async resume task gets > scheduled. > > The bug occurs because xen's do_suspend calls dpm_resume_start while > only the timer of the boot CPU has been resumed (when xen_suspend called > syscore_resume), before calling xen_arch_suspend to resume the timers of > the other CPUs. This breaks pci_dev_d3_sleep. > > Thus this patch moves the call to xen_arch_resume before the call to > dpm_resume_start, eliminating the hangs and restoring the stack-like > structure of the suspend/restore procedure. > > Signed-off-by: Jakub Kądziołka <niedzejkob@invisiblethingslab.com> Reviewed-by: Juergen Gross <jgross@suse.com> Juergen
On 3/22/22 9:21 PM, Jakub Kądziołka wrote: > If a xen domain with at least two VCPUs has a PCI device attached which > enters the D3hot state during suspend, the kernel may hang while > resuming, depending on the core on which an async resume task gets > scheduled. > > The bug occurs because xen's do_suspend calls dpm_resume_start while > only the timer of the boot CPU has been resumed (when xen_suspend called > syscore_resume), before calling xen_arch_suspend to resume the timers of > the other CPUs. This breaks pci_dev_d3_sleep. > > Thus this patch moves the call to xen_arch_resume before the call to > dpm_resume_start, eliminating the hangs and restoring the stack-like > structure of the suspend/restore procedure. > > Signed-off-by: Jakub Kądziołka <niedzejkob@invisiblethingslab.com> Applied to for-linus-5.18
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c index 374d36de7f5a..3d5a384d65f7 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -141,6 +141,8 @@ static void do_suspend(void) raw_notifier_call_chain(&xen_resume_notifier, 0, NULL); + xen_arch_resume(); + dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE); if (err) { @@ -148,8 +150,6 @@ static void do_suspend(void) si.cancelled = 1; } - xen_arch_resume(); - out_resume: if (!si.cancelled) xs_resume();
If a xen domain with at least two VCPUs has a PCI device attached which enters the D3hot state during suspend, the kernel may hang while resuming, depending on the core on which an async resume task gets scheduled. The bug occurs because xen's do_suspend calls dpm_resume_start while only the timer of the boot CPU has been resumed (when xen_suspend called syscore_resume), before calling xen_arch_suspend to resume the timers of the other CPUs. This breaks pci_dev_d3_sleep. Thus this patch moves the call to xen_arch_resume before the call to dpm_resume_start, eliminating the hangs and restoring the stack-like structure of the suspend/restore procedure. Signed-off-by: Jakub Kądziołka <niedzejkob@invisiblethingslab.com> --- drivers/xen/manage.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)