* [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() @ 2012-02-23 20:58 Paul E. McKenney 2012-02-28 6:13 ` Srivatsa S. Bhat 2012-02-28 7:19 ` Yong Zhang 0 siblings, 2 replies; 6+ messages in thread From: Paul E. McKenney @ 2012-02-23 20:58 UTC (permalink / raw) To: deepthi; +Cc: linux-kernel, lenb, linux-acpi The acpi_processor_cst_has_changed() function is invoked from a CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0 even though the CPU being hotplugged is some other CPU. In addition, acpi_processor_cst_has_changed() invokes smp_processor_id() without protection, resulting in splats when onlining CPUs. This commit therefore changes the smp_processor_id() to pr->id, as is used elsewhere in the code, for example, in acpi_processor_add(). This works for me, but I don't claim to understand ACPI. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 0e8e2de..9e57b06 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -1159,8 +1159,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) * to make the code that updates C-States be called once. */ - if (smp_processor_id() == 0 && - cpuidle_get_driver() == &acpi_idle_driver) { + if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) { cpuidle_pause_and_lock(); /* Protect against cpu-hotplug */ ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() 2012-02-23 20:58 [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() Paul E. McKenney @ 2012-02-28 6:13 ` Srivatsa S. Bhat 2012-02-28 7:19 ` Yong Zhang 1 sibling, 0 replies; 6+ messages in thread From: Srivatsa S. Bhat @ 2012-02-28 6:13 UTC (permalink / raw) To: paulmck; +Cc: deepthi, linux-kernel, lenb, linux-acpi On 02/24/2012 02:28 AM, Paul E. McKenney wrote: > The acpi_processor_cst_has_changed() function is invoked from a > CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0 > even though the CPU being hotplugged is some other CPU. In addition, > acpi_processor_cst_has_changed() invokes smp_processor_id() without > protection, resulting in splats when onlining CPUs. > > This commit therefore changes the smp_processor_id() to pr->id, as is > used elsewhere in the code, for example, in acpi_processor_add(). > > This works for me, but I don't claim to understand ACPI. > > Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> > This looks like the right fix to me, observing the disparity between what the comment says (and hence what was intended) vs what the code originally did. Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c > index 0e8e2de..9e57b06 100644 > --- a/drivers/acpi/processor_idle.c > +++ b/drivers/acpi/processor_idle.c > @@ -1159,8 +1159,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) > * to make the code that updates C-States be called once. > */ > > - if (smp_processor_id() == 0 && > - cpuidle_get_driver() == &acpi_idle_driver) { > + if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) { > > cpuidle_pause_and_lock(); > /* Protect against cpu-hotplug */ > Regards, Srivatsa S. Bhat ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() 2012-02-23 20:58 [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() Paul E. McKenney 2012-02-28 6:13 ` Srivatsa S. Bhat @ 2012-02-28 7:19 ` Yong Zhang 2012-02-28 13:30 ` Paul E. McKenney 1 sibling, 1 reply; 6+ messages in thread From: Yong Zhang @ 2012-02-28 7:19 UTC (permalink / raw) To: Paul E. McKenney; +Cc: deepthi, linux-kernel, lenb, linux-acpi On Thu, Feb 23, 2012 at 12:58:05PM -0800, Paul E. McKenney wrote: > The acpi_processor_cst_has_changed() function is invoked from a > CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0 > even though the CPU being hotplugged is some other CPU. In addition, > acpi_processor_cst_has_changed() invokes smp_processor_id() without > protection, resulting in splats when onlining CPUs. > > This commit therefore changes the smp_processor_id() to pr->id, as is > used elsewhere in the code, for example, in acpi_processor_add(). > > This works for me, but I don't claim to understand ACPI. > > Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Got the same warning. And the patch works on my side. Tested-by: Yong Zhang <yong.zhang0@gmail.com> > > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c > index 0e8e2de..9e57b06 100644 > --- a/drivers/acpi/processor_idle.c > +++ b/drivers/acpi/processor_idle.c > @@ -1159,8 +1159,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) > * to make the code that updates C-States be called once. > */ > > - if (smp_processor_id() == 0 && > - cpuidle_get_driver() == &acpi_idle_driver) { > + if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) { > > cpuidle_pause_and_lock(); > /* Protect against cpu-hotplug */ > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Only stand for myself ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() 2012-02-28 7:19 ` Yong Zhang @ 2012-02-28 13:30 ` Paul E. McKenney 2012-02-28 20:57 ` Rafael J. Wysocki 0 siblings, 1 reply; 6+ messages in thread From: Paul E. McKenney @ 2012-02-28 13:30 UTC (permalink / raw) To: Yong Zhang; +Cc: deepthi, linux-kernel, lenb, linux-acpi On Tue, Feb 28, 2012 at 03:19:43PM +0800, Yong Zhang wrote: > On Thu, Feb 23, 2012 at 12:58:05PM -0800, Paul E. McKenney wrote: > > The acpi_processor_cst_has_changed() function is invoked from a > > CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0 > > even though the CPU being hotplugged is some other CPU. In addition, > > acpi_processor_cst_has_changed() invokes smp_processor_id() without > > protection, resulting in splats when onlining CPUs. > > > > This commit therefore changes the smp_processor_id() to pr->id, as is > > used elsewhere in the code, for example, in acpi_processor_add(). > > > > This works for me, but I don't claim to understand ACPI. > > > > Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> > > Got the same warning. > And the patch works on my side. > > Tested-by: Yong Zhang <yong.zhang0@gmail.com> Thank you, I have added your Tested-by (and Srivatsa's Reviewed-by, for that matter). Any takers for this, or should I just push it up the -tip tree? Thanx, Paul > > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c > > index 0e8e2de..9e57b06 100644 > > --- a/drivers/acpi/processor_idle.c > > +++ b/drivers/acpi/processor_idle.c > > @@ -1159,8 +1159,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) > > * to make the code that updates C-States be called once. > > */ > > > > - if (smp_processor_id() == 0 && > > - cpuidle_get_driver() == &acpi_idle_driver) { > > + if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) { > > > > cpuidle_pause_and_lock(); > > /* Protect against cpu-hotplug */ > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ > > -- > Only stand for myself > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() 2012-02-28 13:30 ` Paul E. McKenney @ 2012-02-28 20:57 ` Rafael J. Wysocki 2012-02-28 21:27 ` Paul E. McKenney 0 siblings, 1 reply; 6+ messages in thread From: Rafael J. Wysocki @ 2012-02-28 20:57 UTC (permalink / raw) To: paulmck, lenb; +Cc: Yong Zhang, deepthi, linux-kernel, linux-acpi On Tuesday, February 28, 2012, Paul E. McKenney wrote: > On Tue, Feb 28, 2012 at 03:19:43PM +0800, Yong Zhang wrote: > > On Thu, Feb 23, 2012 at 12:58:05PM -0800, Paul E. McKenney wrote: > > > The acpi_processor_cst_has_changed() function is invoked from a > > > CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0 > > > even though the CPU being hotplugged is some other CPU. In addition, > > > acpi_processor_cst_has_changed() invokes smp_processor_id() without > > > protection, resulting in splats when onlining CPUs. > > > > > > This commit therefore changes the smp_processor_id() to pr->id, as is > > > used elsewhere in the code, for example, in acpi_processor_add(). > > > > > > This works for me, but I don't claim to understand ACPI. > > > > > > Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> > > > > Got the same warning. > > And the patch works on my side. > > > > Tested-by: Yong Zhang <yong.zhang0@gmail.com> > > Thank you, I have added your Tested-by (and Srivatsa's Reviewed-by, > for that matter). > > Any takers for this, or should I just push it up the -tip tree? I think this patch is for Len, either through ACPI, or through the idle tree. Len? Anyway: Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Thanks, Rafael > > > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c > > > index 0e8e2de..9e57b06 100644 > > > --- a/drivers/acpi/processor_idle.c > > > +++ b/drivers/acpi/processor_idle.c > > > @@ -1159,8 +1159,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) > > > * to make the code that updates C-States be called once. > > > */ > > > > > > - if (smp_processor_id() == 0 && > > > - cpuidle_get_driver() == &acpi_idle_driver) { > > > + if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) { > > > > > > cpuidle_pause_and_lock(); > > > /* Protect against cpu-hotplug */ > > > > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > > the body of a message to majordomo@vger.kernel.org > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > Please read the FAQ at http://www.tux.org/lkml/ > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() 2012-02-28 20:57 ` Rafael J. Wysocki @ 2012-02-28 21:27 ` Paul E. McKenney 0 siblings, 0 replies; 6+ messages in thread From: Paul E. McKenney @ 2012-02-28 21:27 UTC (permalink / raw) To: Rafael J. Wysocki; +Cc: lenb, Yong Zhang, deepthi, linux-kernel, linux-acpi On Tue, Feb 28, 2012 at 09:57:53PM +0100, Rafael J. Wysocki wrote: > On Tuesday, February 28, 2012, Paul E. McKenney wrote: > > On Tue, Feb 28, 2012 at 03:19:43PM +0800, Yong Zhang wrote: > > > On Thu, Feb 23, 2012 at 12:58:05PM -0800, Paul E. McKenney wrote: > > > > The acpi_processor_cst_has_changed() function is invoked from a > > > > CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0 > > > > even though the CPU being hotplugged is some other CPU. In addition, > > > > acpi_processor_cst_has_changed() invokes smp_processor_id() without > > > > protection, resulting in splats when onlining CPUs. > > > > > > > > This commit therefore changes the smp_processor_id() to pr->id, as is > > > > used elsewhere in the code, for example, in acpi_processor_add(). > > > > > > > > This works for me, but I don't claim to understand ACPI. > > > > > > > > Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> > > > > > > Got the same warning. > > > And the patch works on my side. > > > > > > Tested-by: Yong Zhang <yong.zhang0@gmail.com> > > > > Thank you, I have added your Tested-by (and Srivatsa's Reviewed-by, > > for that matter). > > > > Any takers for this, or should I just push it up the -tip tree? > > I think this patch is for Len, either through ACPI, or through the idle tree. > Len? Whichever way it is supposed to go, it reminds me of the need for it every time I forget to merge it in before testing. ;-) > Anyway: > > Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Thank you, applied! The patch appears below with the recent review, testing, and ack. Thanx, Paul ------------------------------------------------------------------------ acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() The acpi_processor_cst_has_changed() function is invoked from a CPU_ONLINE or CPU_DEAD function, which might well execute on CPU 0 even though the CPU being hotplugged is some other CPU. In addition, acpi_processor_cst_has_changed() invokes smp_processor_id() without protection, resulting in splats when onlining CPUs. This commit therefore changes the smp_processor_id() to pr->id, as is used elsewhere in the code, for example, in acpi_processor_add(). Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Tested-by: Yong Zhang <yong.zhang0@gmail.com> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 0e8e2de..9e57b06 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -1159,8 +1159,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) * to make the code that updates C-States be called once. */ - if (smp_processor_id() == 0 && - cpuidle_get_driver() == &acpi_idle_driver) { + if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) { cpuidle_pause_and_lock(); /* Protect against cpu-hotplug */ ^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2012-02-28 21:28 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-02-23 20:58 [PATCH RFC] acpi: Fix unprotected smp_processor_id() in acpi_processor_cst_has_changed() Paul E. McKenney 2012-02-28 6:13 ` Srivatsa S. Bhat 2012-02-28 7:19 ` Yong Zhang 2012-02-28 13:30 ` Paul E. McKenney 2012-02-28 20:57 ` Rafael J. Wysocki 2012-02-28 21:27 ` Paul E. McKenney
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