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authorMarc Zyngier <marc.zyngier@arm.com>2015-03-06 16:37:43 +0000
committerJason Cooper <jason@lakedaemon.net>2015-03-08 05:33:00 +0000
commit3e39e8f56c1c67cdd1e8f06da0d6b7c831818c76 (patch)
treeb7332e00d00a4e1f1a13b01b8da7237b644e5eb0 /drivers
parente8137f4f5088d763ced1db82d3974336b76e1bd2 (diff)
irqchip: gicv3-its: Fix unsafe locking reported by lockdep
When compiled with CONFIG_LOCKDEP, the kernel shouts badly, saying that my locking is unsafe. I'm afraid the kernel is right: CPU0 CPU1 ---- ---- lock(&its->lock); local_irq_disable(); lock(&irq_desc_lock_class); lock(&its->lock); <Interrupt> lock(&irq_desc_lock_class); *** DEADLOCK *** The fix is to always take its->lock with interrupts disabled. Reported-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Link: https://lkml.kernel.org/r/1425659870-11832-5-git-send-email-marc.zyngier@arm.com Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/irqchip/irq-gic-v3-its.c23
1 files changed, 14 insertions, 9 deletions
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 46b9441b36bd..6850141d6524 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -416,13 +416,14 @@ static void its_send_single_command(struct its_node *its,
{
struct its_cmd_block *cmd, *sync_cmd, *next_cmd;
struct its_collection *sync_col;
+ unsigned long flags;
- raw_spin_lock(&its->lock);
+ raw_spin_lock_irqsave(&its->lock, flags);
cmd = its_allocate_entry(its);
if (!cmd) { /* We're soooooo screewed... */
pr_err_ratelimited("ITS can't allocate, dropping command\n");
- raw_spin_unlock(&its->lock);
+ raw_spin_unlock_irqrestore(&its->lock, flags);
return;
}
sync_col = builder(cmd, desc);
@@ -442,7 +443,7 @@ static void its_send_single_command(struct its_node *its,
post:
next_cmd = its_post_commands(its);
- raw_spin_unlock(&its->lock);
+ raw_spin_unlock_irqrestore(&its->lock, flags);
its_wait_for_range_completion(its, cmd, next_cmd);
}
@@ -1037,8 +1038,9 @@ static void its_cpu_init_collection(void)
static struct its_device *its_find_device(struct its_node *its, u32 dev_id)
{
struct its_device *its_dev = NULL, *tmp;
+ unsigned long flags;
- raw_spin_lock(&its->lock);
+ raw_spin_lock_irqsave(&its->lock, flags);
list_for_each_entry(tmp, &its->its_device_list, entry) {
if (tmp->device_id == dev_id) {
@@ -1047,7 +1049,7 @@ static struct its_device *its_find_device(struct its_node *its, u32 dev_id)
}
}
- raw_spin_unlock(&its->lock);
+ raw_spin_unlock_irqrestore(&its->lock, flags);
return its_dev;
}
@@ -1057,6 +1059,7 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
{
struct its_device *dev;
unsigned long *lpi_map;
+ unsigned long flags;
void *itt;
int lpi_base;
int nr_lpis;
@@ -1092,9 +1095,9 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
dev->device_id = dev_id;
INIT_LIST_HEAD(&dev->entry);
- raw_spin_lock(&its->lock);
+ raw_spin_lock_irqsave(&its->lock, flags);
list_add(&dev->entry, &its->its_device_list);
- raw_spin_unlock(&its->lock);
+ raw_spin_unlock_irqrestore(&its->lock, flags);
/* Bind the device to the first possible CPU */
cpu = cpumask_first(cpu_online_mask);
@@ -1108,9 +1111,11 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
static void its_free_device(struct its_device *its_dev)
{
- raw_spin_lock(&its_dev->its->lock);
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&its_dev->its->lock, flags);
list_del(&its_dev->entry);
- raw_spin_unlock(&its_dev->its->lock);
+ raw_spin_unlock_irqrestore(&its_dev->its->lock, flags);
kfree(its_dev->itt);
kfree(its_dev);
}