From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Peter Zijlstra <a.p.zijlstra@chello.nl>,
Joerg Roedel <joerg.roedel@amd.com>,
linux-kernel@vger.kernel.org
Subject: fix BUG: using smp_processor_id() in preemptible code (resend)
Date: Wed, 18 Aug 2010 12:11:58 +0300 [thread overview]
Message-ID: <20100818091157.GA5238@swordfish.minsk.epam.com> (raw)
Hello,
[ 100.666169] lockdep: fixing up alternatives.
[ 100.666183] SMP alternatives: switching to UP code
[ 106.942505] BUG: using smp_processor_id() in preemptible [00000000] code: bash/5165
[ 106.942541] caller is thermal_throttle_add_dev+0x20/0xa4
[ 106.942548] Pid: 5165, comm: bash Not tainted 2.6.36-rc1-dbg-git1-00187-g358afc9-dirty #132
[ 106.942553] Call Trace:
[ 106.942565] [<ffffffff811f6c01>] debug_smp_processor_id+0xc9/0xe4
[ 106.942571] [<ffffffff8136d377>] thermal_throttle_add_dev+0x20/0xa4
[ 106.942578] [<ffffffff8136d44d>] thermal_throttle_cpu_callback+0x52/0xb5
[ 106.942587] [<ffffffff810573f8>] notifier_call_chain+0x32/0x5e
[ 106.942595] [<ffffffff8103c840>] ? cpu_maps_update_begin+0x12/0x14
[ 106.942602] [<ffffffff81057443>] __raw_notifier_call_chain+0x9/0xb
[ 106.942609] [<ffffffff8103c703>] __cpu_notify+0x1b/0x2d
[ 106.942616] [<ffffffff8136f57d>] _cpu_up+0x6b/0xe9
[ 106.942622] [<ffffffff8136f645>] cpu_up+0x4a/0x57
[ 106.942629] [<ffffffff81363f77>] store_online+0x41/0x6e
[ 106.942637] [<ffffffff81291b4f>] sysdev_store+0x1b/0x1d
[ 106.942644] [<ffffffff81132186>] sysfs_write_file+0x103/0x13f
[ 106.942653] [<ffffffff810db026>] vfs_write+0xb0/0x14f
[ 106.942659] [<ffffffff810db2c2>] sys_write+0x45/0x6c
[ 106.942668] [<ffffffff81002002>] system_call_fastpath+0x16/0x1b
I have several solutions. Please kindly review.
The first one is:
diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index c2a8b26..1269661 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -205,7 +205,9 @@ static int therm_throt_process(bool new_event, int event, int level)
static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
{
int err;
- struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
+ int cpu = get_cpu();
+ struct cpuinfo_x86 *c = &cpu_data(cpu);
+ put_cpu();
err = sysfs_create_group(&sys_dev->kobj, &thermal_attr_group);
if (err)
Should we call smp_processor_id/get_cpu in thermal_throttle_add_dev?
We know the cpu when calling thermal_throttle_add_dev (in thermal_throttle_cpu_callback and
thermal_throttle_init_device) so we can pass the cpu number when calling it.
My second solution is:
diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index c2a8b26..bcd8499 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -202,11 +202,12 @@ static int therm_throt_process(bool new_event, int event, int level)
#ifdef CONFIG_SYSFS
/* Add/Remove thermal_throttle interface for CPU device: */
-static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev)
+static __cpuinit int thermal_throttle_add_dev(struct sys_device *sys_dev,
+ unsigned int cpu)
{
int err;
- struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
-
+ struct cpuinfo_x86 *c = &cpu_data(cpu);
+
err = sysfs_create_group(&sys_dev->kobj, &thermal_attr_group);
if (err)
return err;
@@ -251,7 +252,7 @@ thermal_throttle_cpu_callback(struct notifier_block *nfb,
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
mutex_lock(&therm_cpu_lock);
- err = thermal_throttle_add_dev(sys_dev);
+ err = thermal_throttle_add_dev(sys_dev, cpu);
mutex_unlock(&therm_cpu_lock);
WARN_ON(err);
break;
@@ -287,7 +288,7 @@ static __init int thermal_throttle_init_device(void)
#endif
/* connect live CPUs to sysfs */
for_each_online_cpu(cpu) {
- err = thermal_throttle_add_dev(get_cpu_sysdev(cpu));
+ err = thermal_throttle_add_dev(get_cpu_sysdev(cpu), cpu);
WARN_ON(err);
}
#ifdef CONFIG_HOTPLUG_CPU
next reply other threads:[~2010-08-18 9:12 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-18 9:11 Sergey Senozhatsky [this message]
2010-08-19 15:04 ` Maciej Rutecki
2010-08-19 17:03 ` Roedel, Joerg
2010-08-19 21:46 ` H. Peter Anvin
2010-08-20 7:36 ` [PATCH] fix BUG using smp_processor_id() in preemptible thermal_throttle_add_dev Sergey Senozhatsky
2010-08-21 4:43 ` [tip:x86/urgent] x86, hwmon: Fix unsafe smp_processor_id() in thermal_throttle_add_dev tip-bot for Sergey Senozhatsky
2010-08-21 5:51 ` Fenghua Yu
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