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Groups > linux.kernel > #1554800
| From | "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel |
| Date | 2017-01-10 00:40 +0100 |
| Message-ID | <sXRHH-231-9@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <sXxpD-5ZY-5@gated-at.bofh.it> <sXy2m-6t3-15@gated-at.bofh.it> <sXEAO-2pA-11@gated-at.bofh.it> <sXQsi-1ot-19@gated-at.bofh.it> <sXRom-1WC-19@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Jan 10, 2017 at 12:15:01AM +0100, Borislav Petkov wrote:
> On Mon, Jan 09, 2017 at 02:18:31PM -0800, Paul E. McKenney wrote:
> > @@ -690,6 +690,8 @@ void synchronize_rcu_expedited(void)
> > {
> > struct rcu_state *rsp = rcu_state_p;
> >
> > + if (!rcu_scheduler_active)
> > + return;
> > _synchronize_rcu_expedited(rsp, sync_rcu_exp_handler);
> > }
> > EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
>
> That doesn't work and it is because of those damn what goes before what
> boot sequence issues :-\
>
> We have:
>
> rest_init()
> |-> rcu_scheduler_starting() ---> that sets rcu_scheduler_active = 1;
> |-> kernel_thread(kernel_init, NULL, CLONE_FS);
> |-> kernel_init()
> |-> kernel_init_freeable()
> |-> native_smp_prepare_cpus(setup_max_cpus)
> |-> default_setup_apic_routing
> |-> enable_IR_x2apic
> |-> irq_remapping_prepare
> |-> amd_iommu_prepare
> |-> iommu_go_to_state
> |-> acpi_put_table(ivrs_base);
> |-> acpi_tb_put_table(table_desc);
> |-> acpi_tb_invalidate_table(table_desc);
> |-> acpi_tb_release_table(...)
> |-> acpi_os_unmap_memory
> |-> acpi_os_unmap_iomem
> |-> acpi_os_map_cleanup
> |-> synchronize_rcu_expedited()
>
> Now here we have rcu_scheduler_active already set so the test doesn't
> hit and we hang.
>
> So we must do it differently.
Yeah, there is a window just as the scheduler is starting where things don't
work.
We could move rcu_scheduler_starting() later, as long as there
is no chance of preemption or context switch before it is invoked.
Would that help in this case, or are we already context switching before
acpi_os_map_cleanup() is invoked? (If we are already context switching,
short-circuiting synchronize_rcu_expedited() would be a bug.)
Thanx, Paul
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Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> - 2017-01-08 00:40 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-08 01:10 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Rafael J. Wysocki" <rafael@kernel.org> - 2017-01-08 01:30 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-08 01:40 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Rafael J. Wysocki" <rafael@kernel.org> - 2017-01-08 02:00 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-08 02:10 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Rafael J. Wysocki" <rafael@kernel.org> - 2017-01-08 02:50 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Rafael J. Wysocki" <rafael@kernel.org> - 2017-01-08 03:30 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-08 14:10 +0100
RE: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Zheng, Lv" <lv.zheng@intel.com> - 2017-01-09 03:00 +0100
RE: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Zheng, Lv" <lv.zheng@intel.com> - 2017-01-09 03:40 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-09 10:40 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-01-09 23:20 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Rafael J. Wysocki" <rafael@kernel.org> - 2017-01-09 23:30 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-01-10 00:20 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-10 00:20 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-01-10 00:40 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-10 00:50 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-10 01:00 +0100
RE: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Zheng, Lv" <lv.zheng@intel.com> - 2017-01-10 01:50 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Rafael J. Wysocki" <rafael@kernel.org> - 2017-01-10 02:30 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-01-10 03:30 +0100
RE: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Zheng, Lv" <lv.zheng@intel.com> - 2017-01-10 06:50 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-01-10 07:00 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-11 10:30 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-01-11 11:00 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-11 11:10 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-01-11 11:30 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-10 10:50 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Rafael J. Wysocki" <rafael@kernel.org> - 2017-01-11 04:50 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-11 10:50 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-01-10 01:00 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Rafael J. Wysocki" <rafael@kernel.org> - 2017-01-10 00:50 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-01-10 01:30 +0100
RE: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Zheng, Lv" <lv.zheng@intel.com> - 2017-01-09 06:30 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Jörg Rödel <joro@8bytes.org> - 2017-01-09 12:00 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2017-01-09 23:50 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Borislav Petkov <bp@alien8.de> - 2017-01-10 00:00 +0100
Re: 174cc7187e6f ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel Jörg Rödel <joro@8bytes.org> - 2017-01-10 15:00 +0100
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