From: Dave Jones <davej@redhat.com>
To: "Jeff V. Merkey" <jmerkey@wolfmountaingroup.com>
Cc: Linux kernel <linux-kernel@vger.kernel.org>,
venki@gelk.kernelslacker.org
Subject: Re: Preemption Broken: centrino_target busted under SMP on 2.6.20.4
Date: Thu, 5 Apr 2007 16:50:34 -0400 [thread overview]
Message-ID: <20070405205034.GB3605@redhat.com> (raw)
In-Reply-To: <46155CFF.70701@wolfmountaingroup.com>
On Thu, Apr 05, 2007 at 02:33:03PM -0600, Jeff V. Merkey wrote:
>
> BUG: using smp_processor_id() in preemptible [00000001] code:
> kondemand/0/2473
> caller is centrino_target+0xfb/0x600
> [<401e3646>] debug_smp_processor_id+0x9e/0xb0
> [<40112afb>] centrino_target+0xfb/0x600
> [<40112a00>] centrino_target+0x0/0x600
> [<40305bd9>] __cpufreq_driver_target+0x5c/0x6b
> [<f897a537>] do_dbs_timer+0x1bc/0x208 [cpufreq_ondemand]
> [<40134a46>] run_workqueue+0x85/0x125
> [<40374f7f>] _spin_lock_irqsave+0x18/0x66
> [<f897a37b>] do_dbs_timer+0x0/0x208 [cpufreq_ondemand]
> [<401353fb>] worker_thread+0xf9/0x124
> [<401213b9>] default_wake_function+0x0/0xc
> [<40135302>] worker_thread+0x0/0x124
> [<40137b37>] kthread+0xb0/0xd9
> [<40137a87>] kthread+0x0/0xd9
> [<40104b2f>] kernel_thread_helper+0x7/0x10
Given speedstep-centrino is obsoleted in favour of acpi-cpufreq,
I'm reluctant to spend too much time turd-polishing.
This big-hammer diff should fix this..
Dave
diff --git a/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c b/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
index f43b987..824d0a2 100644
--- a/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
+++ b/arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c
@@ -708,6 +708,7 @@ static int centrino_target (struct cpufreq_policy *policy,
saved_mask = current->cpus_allowed;
first_cpu = 1;
cpus_clear(covered_cpus);
+ preempt_disable();
for_each_cpu_mask(j, online_policy_cpus) {
/*
* Support for SMP systems.
@@ -798,6 +799,7 @@ static int centrino_target (struct cpufreq_policy *policy,
}
migrate_end:
+ preempt_enable();
set_cpus_allowed(current, saved_mask);
return 0;
}
--
http://www.codemonkey.org.uk
next prev parent reply other threads:[~2007-04-05 20:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-05 20:33 Preemption Broken: centrino_target busted under SMP on 2.6.20.4 Jeff V. Merkey
2007-04-05 20:50 ` Dave Jones [this message]
2007-04-10 0:26 ` Andrew Morton
2007-04-10 2:31 ` Dave Jones
2007-04-10 2:41 ` Andrew Morton
2007-04-10 3:05 ` Dave Jones
2007-04-10 3:08 ` Dave Jones
2007-04-10 3:51 ` Andrew Morton
2007-04-10 4:29 ` Dave Jones
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