Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753908AbZDPBUa (ORCPT ); Wed, 15 Apr 2009 21:20:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752098AbZDPBUS (ORCPT ); Wed, 15 Apr 2009 21:20:18 -0400 Received: from mga07.intel.com ([143.182.124.22]:65095 "EHLO azsmga101.ch.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751988AbZDPBUQ (ORCPT ); Wed, 15 Apr 2009 21:20:16 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.40,195,1239001200"; d="scan'208";a="131980295" Subject: Re: [PATCH] x86, acpi_cpufreq: Fix the NULL pointer dereference in get_measured_perf From: "Zhang, Yanmin" To: "Pallipadi, Venkatesh" Cc: Rusty Russell , LKML , "cpufreq@vger.kernel.org" , "linux-acpi@vger.kernel.org" , lenb@kernel.org In-Reply-To: <20090415173733.GA26685@linux-os.sc.intel.com> References: <1239775283.2567.846.camel@ymzhang> <200904152044.17658.rusty@rustcorp.com.au> <20090415173733.GA26685@linux-os.sc.intel.com> Content-Type: text/plain Date: Thu, 16 Apr 2009 09:20:43 +0800 Message-Id: <1239844843.2567.856.camel@ymzhang> Mime-Version: 1.0 X-Mailer: Evolution 2.22.1 (2.22.1-2.fc9) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5442 Lines: 140 On Wed, 2009-04-15 at 10:37 -0700, Pallipadi, Venkatesh wrote: > Patch below fixes the problem. > Yanmin can you please verify. It does work. > Len please push this patch along to linus. > > Thanks, > Venki > > > Fix for a regression that was introduced by earlier commit > > commit 18b2646fe3babeb40b34a0c1751e0bf5adfdc64c > Author: Venkatesh Pallipadi > Date: Mon Apr 6 11:26:08 2009 -0700 > > Regression resulted in the below error happened on systems with > software coordination where per_cpu acpi data will not be initiated for > secondary CPUs in a P-state domain. > > On Tue, 2009-04-14 at 23:01 -0700, Zhang, Yanmin wrote: > My machine hanged with kernel 2.6.30-rc2 when script read > > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor. > > > > opps happens in get_measured_perf: > > > > cur.aperf.whole = readin.aperf.whole - > > per_cpu(drv_data, cpu)->saved_aperf; > > > > Because per_cpu(drv_data, cpu)=NULL. > > > > So function get_measured_perf should check if (per_cpu(drv_data, > > cpu)==NULL) > > and return 0 if it's NULL. > > --------------sys log------------------ > > BUG: unable to handle kernel NULL pointer dereference at > 0000000000000020 > IP: [] get_measured_perf+0x4a/0xf9 > PGD a7dd88067 PUD a7ccf5067 PMD 0 > Oops: 0000 [#1] SMP > last sysfs file: /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > CPU 0 > Modules linked in: video output > Pid: 2091, comm: kondemand/0 Not tainted 2.6.30-rc2 #1 MP Server > RIP: 0010:[] [] > get_measured_perf+0x4a/0xf9 > RSP: 0018:ffff880a7d56de20 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: 00000046241a42b6 RCX: ffff88004d219000 > RDX: 000000000000b660 RSI: 0000000000000020 RDI: 0000000000000001 > RBP: ffff880a7f052000 R08: 00000046241a42b6 R09: ffffffff807639f0 > R10: 00000000ffffffea R11: ffffffff802207f4 R12: ffff880a7f052000 > R13: ffff88004d20e460 R14: 0000000000ddd5a6 R15: 0000000000000001 > FS: 0000000000000000(0000) GS:ffff88004d200000(0000) > knlGS:0000000000000000 > CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b > CR2: 0000000000000020 CR3: 0000000a7f1bf000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process kondemand/0 (pid: 2091, threadinfo ffff880a7d56c000, task > ffff880a7d4d18c0) > Stack: > ffff880a7f052078 ffffffff803efd54 00000046241a42b6 000000462ffa9e95 > 0000000000000001 0000000000000001 00000000ffffffea ffffffff8064f41a > 0000000000000012 0000000000000012 ffff880a7f052000 ffffffff80650547 > Call Trace: > [] ? kobject_get+0x12/0x17 > [] ? __cpufreq_driver_getavg+0x42/0x57 > [] ? do_dbs_timer+0x147/0x272 > [] ? do_dbs_timer+0x0/0x272 > [] ? worker_thread+0x15b/0x1f5 > [] ? autoremove_wake_function+0x0/0x2e > [] ? worker_thread+0x0/0x1f5 > [] ? kthread+0x54/0x83 > [] ? child_rip+0xa/0x20 > [] ? kthread+0x0/0x83 > [] ? child_rip+0x0/0x20 > Code: 99 a6 03 00 31 c9 85 c0 0f 85 c3 00 00 00 89 df 4c 8b 44 24 10 48 > c7 c2 60 b6 00 00 48 8b 0c fd e0 30 a5 80 4c 89 c3 48 8b 04 0a <48> 2b > 58 20 48 8b 44 24 18 48 89 1c 24 48 8b 34 0a 48 2b 46 28 > RIP [] get_measured_perf+0x4a/0xf9 > RSP > CR2: 0000000000000020 > ---[ end trace 2b8fac9a49e19ad4 ]--- > > Reported-by: "Zhang, Yanmin" > Signed-off-by: Venkatesh Pallipadi > --- > arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 15 ++++++++++----- > 1 files changed, 10 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c > index 837c2c4..d722b8d 100644 > --- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c > +++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c > @@ -68,11 +68,16 @@ struct acpi_cpufreq_data { > unsigned int max_freq; > unsigned int resume; > unsigned int cpu_feature; > - u64 saved_aperf, saved_mperf; > }; > > static DEFINE_PER_CPU(struct acpi_cpufreq_data *, drv_data); > > +struct acpi_msr_data { > + u64 saved_aperf, saved_mperf; > +}; > + > +static DEFINE_PER_CPU(struct acpi_msr_data, msr_data); > + > DEFINE_TRACE(power_mark); > > /* acpi_perf_data is a pointer to percpu data. */ > @@ -281,11 +286,11 @@ static unsigned int get_measured_perf(struct cpufreq_policy *policy, > return 0; > > cur.aperf.whole = readin.aperf.whole - > - per_cpu(drv_data, cpu)->saved_aperf; > + per_cpu(msr_data, cpu).saved_aperf; > cur.mperf.whole = readin.mperf.whole - > - per_cpu(drv_data, cpu)->saved_mperf; > - per_cpu(drv_data, cpu)->saved_aperf = readin.aperf.whole; > - per_cpu(drv_data, cpu)->saved_mperf = readin.mperf.whole; > + per_cpu(msr_data, cpu).saved_mperf; > + per_cpu(msr_data, cpu).saved_aperf = readin.aperf.whole; > + per_cpu(msr_data, cpu).saved_mperf = readin.mperf.whole; > > #ifdef __i386__ > /* -- 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/