This is a note to let you know that I've just added the patch titled xen/acpi: upload PM state from init-domain to Xen to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xen-acpi-upload-pm-state-from-init-domain-to-xen.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 1914f0cd203c941bba72f9452c8290324f1ef3dc Mon Sep 17 00:00:00 2001 From: Ankur Arora <ankur.a.arora@xxxxxxxxxx> Date: Tue, 21 Mar 2017 15:43:38 -0700 Subject: xen/acpi: upload PM state from init-domain to Xen From: Ankur Arora <ankur.a.arora@xxxxxxxxxx> commit 1914f0cd203c941bba72f9452c8290324f1ef3dc upstream. This was broken in commit cd979883b9ed ("xen/acpi-processor: fix enabling interrupts on syscore_resume"). do_suspend (from xen/manage.c) and thus xen_resume_notifier never get called on the initial-domain at resume (it is if running as guest.) The rationale for the breaking change was that upload_pm_data() potentially does blocking work in syscore_resume(). This patch addresses the original issue by scheduling upload_pm_data() to execute in workqueue context. Cc: Stanislaw Gruszka <sgruszka@xxxxxxxxxx> Based-on-patch-by: Konrad Wilk <konrad.wilk@xxxxxxxxxx> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Reviewed-by: Stanislaw Gruszka <sgruszka@xxxxxxxxxx> Signed-off-by: Ankur Arora <ankur.a.arora@xxxxxxxxxx> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/xen/xen-acpi-processor.c | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-) --- a/drivers/xen/xen-acpi-processor.c +++ b/drivers/xen/xen-acpi-processor.c @@ -27,10 +27,10 @@ #include <linux/init.h> #include <linux/module.h> #include <linux/types.h> +#include <linux/syscore_ops.h> #include <linux/acpi.h> #include <acpi/processor.h> #include <xen/xen.h> -#include <xen/xen-ops.h> #include <xen/interface/platform.h> #include <asm/xen/hypercall.h> @@ -466,15 +466,33 @@ static int xen_upload_processor_pm_data( return rc; } -static int xen_acpi_processor_resume(struct notifier_block *nb, - unsigned long action, void *data) +static void xen_acpi_processor_resume_worker(struct work_struct *dummy) { + int rc; + bitmap_zero(acpi_ids_done, nr_acpi_bits); - return xen_upload_processor_pm_data(); + + rc = xen_upload_processor_pm_data(); + if (rc != 0) + pr_info("ACPI data upload failed, error = %d\n", rc); +} + +static void xen_acpi_processor_resume(void) +{ + static DECLARE_WORK(wq, xen_acpi_processor_resume_worker); + + /* + * xen_upload_processor_pm_data() calls non-atomic code. + * However, the context for xen_acpi_processor_resume is syscore + * with only the boot CPU online and in an atomic context. + * + * So defer the upload for some point safer. + */ + schedule_work(&wq); } -struct notifier_block xen_acpi_processor_resume_nb = { - .notifier_call = xen_acpi_processor_resume, +static struct syscore_ops xap_syscore_ops = { + .resume = xen_acpi_processor_resume, }; static int __init xen_acpi_processor_init(void) @@ -527,7 +545,7 @@ static int __init xen_acpi_processor_ini if (rc) goto err_unregister; - xen_resume_notifier_register(&xen_acpi_processor_resume_nb); + register_syscore_ops(&xap_syscore_ops); return 0; err_unregister: @@ -544,7 +562,7 @@ static void __exit xen_acpi_processor_ex { int i; - xen_resume_notifier_unregister(&xen_acpi_processor_resume_nb); + unregister_syscore_ops(&xap_syscore_ops); kfree(acpi_ids_done); kfree(acpi_id_present); kfree(acpi_id_cst_present); Patches currently in stable-queue which might be from ankur.a.arora@xxxxxxxxxx are queue-4.4/xen-acpi-upload-pm-state-from-init-domain-to-xen.patch