From: Dave Jones <davej@redhat.com>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Thomas Renninger <trenn@suse.de>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [BUGFIX] cpufreq: dont BUG_ON uninitialized policy cpu
Date: Wed, 13 Jan 2010 01:32:46 -0500 [thread overview]
Message-ID: <20100113063246.GA20803@redhat.com> (raw)
In-Reply-To: <20100113051438.GA32519@localhost>
On Wed, Jan 13, 2010 at 01:14:38PM +0800, Wu Fengguang wrote:
> Remove a BUG_ON which is always triggered here after commit 0b19a310eebb93:
>
> --- linux-mm.orig/drivers/cpufreq/cpufreq.c 2010-01-13 13:06:03.000000000 +0800
> +++ linux-mm/drivers/cpufreq/cpufreq.c 2010-01-13 13:06:57.000000000 +0800
> @@ -72,7 +72,8 @@ int lock_policy_rwsem_##mode \
> (int cpu) \
> { \
> int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
> - BUG_ON(policy_cpu == -1); \
> + if (policy_cpu == -1) \
> + return -1; \
> down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
> if (unlikely(!cpu_online(cpu))) { \
> up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
So instead of always BUG'ing, we'll always fail to get the lock ?
How can this be correct ?
This makes no sense. cpufreq_update_policy shouldn't be called without
an existing policy. Can someone send me the full trace ?
Andrew cc'd me on a revert of Thomas's last patch to this file,
but again, no trace, and I can't find the mails he refers to.
Dave
next prev parent reply other threads:[~2010-01-13 6:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-13 5:14 [BUGFIX] cpufreq: dont BUG_ON uninitialized policy cpu Wu Fengguang
2010-01-13 6:32 ` Dave Jones [this message]
2010-01-13 12:42 ` Thomas Renninger
2010-01-13 12:48 ` Wu Fengguang
2010-01-13 15:59 ` Dave Jones
2010-01-14 2:42 ` Wu Fengguang
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