[tip:core/locking] intel_idle: Convert i7300_idle_lock to raw_spinlock

From: tip-bot for Mike Galbraith
Date: Thu Feb 14 2013 - 12:55:40 EST


Commit-ID: 56384eba0f06a834e4c202d0a65e14f55896b67f
Gitweb: http://git.kernel.org/tip/56384eba0f06a834e4c202d0a65e14f55896b67f
Author: Mike Galbraith <efault@xxxxxx>
AuthorDate: Wed, 7 Dec 2011 12:48:42 +0100
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 14 Feb 2013 18:39:06 +0100

intel_idle: Convert i7300_idle_lock to raw_spinlock

24 core Intel box's first exposure to 3.0.12-rt30-rc3 didn't go well.

[ 27.104159] i7300_idle: loaded v1.55
[ 27.104192] BUG: scheduling while atomic: swapper/2/0/0x00000002
[ 27.104309] Pid: 0, comm: swapper/2 Tainted: G N 3.0.12-rt30-rc3-rt #1
[ 27.104317] Call Trace:
[ 27.104338] [<ffffffff810046a5>] dump_trace+0x85/0x2e0
[ 27.104372] [<ffffffff8144eb00>] thread_return+0x12b/0x30b
[ 27.104381] [<ffffffff8144f1b9>] schedule+0x29/0xb0
[ 27.104389] [<ffffffff814506e5>] rt_spin_lock_slowlock+0xc5/0x240
[ 27.104401] [<ffffffffa01f818f>] i7300_idle_notifier+0x3f/0x360 [i7300_idle]
[ 27.104415] [<ffffffff814546c7>] notifier_call_chain+0x37/0x70
[ 27.104426] [<ffffffff81454748>] __atomic_notifier_call_chain+0x48/0x70
[ 27.104439] [<ffffffff81001a39>] cpu_idle+0x89/0xb0
[ 27.104449] bad: scheduling from the idle thread!

This lock is taken from interrupt disabled context in the guts of
idle. Convert it to a raw_spinlock.

Signed-off-by: Mike Galbraith <efault@xxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Andy Henroid <andrew.d.henroid@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1323258522.5057.73.camel@xxxxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
drivers/idle/i7300_idle.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/idle/i7300_idle.c b/drivers/idle/i7300_idle.c
index fa080eb..ffeebc7 100644
--- a/drivers/idle/i7300_idle.c
+++ b/drivers/idle/i7300_idle.c
@@ -75,7 +75,7 @@ static unsigned long past_skip;

static struct pci_dev *fbd_dev;

-static spinlock_t i7300_idle_lock;
+static raw_spinlock_t i7300_idle_lock;
static int i7300_idle_active;

static u8 i7300_idle_thrtctl_saved;
@@ -457,7 +457,7 @@ static int i7300_idle_notifier(struct notifier_block *nb, unsigned long val,
idle_begin_time = ktime_get();
}

- spin_lock_irqsave(&i7300_idle_lock, flags);
+ raw_spin_lock_irqsave(&i7300_idle_lock, flags);
if (val == IDLE_START) {

cpumask_set_cpu(smp_processor_id(), idle_cpumask);
@@ -506,7 +506,7 @@ static int i7300_idle_notifier(struct notifier_block *nb, unsigned long val,
}
}
end:
- spin_unlock_irqrestore(&i7300_idle_lock, flags);
+ raw_spin_unlock_irqrestore(&i7300_idle_lock, flags);
return 0;
}

@@ -548,7 +548,7 @@ struct debugfs_file_info {

static int __init i7300_idle_init(void)
{
- spin_lock_init(&i7300_idle_lock);
+ raw_spin_lock_init(&i7300_idle_lock);
total_us = 0;

if (i7300_idle_platform_probe(&fbd_dev, &ioat_dev, forceload))
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/