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authorLinus Torvalds <torvalds@linux-foundation.org>2015-10-04 11:40:09 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2015-10-04 11:40:09 +0100
commit3e519dde1e8a73e59b0eab52575a14a2986283b6 (patch)
tree16e19515f19a239aaa155e927a37d8e59304b202 /kernel
parent2cf30826bbc6c940568be07e8fab0aee02165cf8 (diff)
parent791c76d58465a248cbd1ee422c8075cb90fa615f (diff)
Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner: "This update contains: - Fix for a long standing race affecting /proc/irq/NNN - One line fix for ARM GICV3-ITS counting the wrong data - Warning silencing in ARM GICV3-ITS. Another GCC trying to be overly clever issue" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/gic-v3-its: Count additional LPIs for the aliased devices irqchip/gic-v3-its: Silence warning when its_lpi_alloc_chunks gets inlined genirq: Fix race in register_irq_proc()
Diffstat (limited to 'kernel')
-rw-r--r--kernel/irq/proc.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index e3a8c9577ba6..a50ddc9417ff 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -12,6 +12,7 @@
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
+#include <linux/mutex.h>
#include "internals.h"
@@ -323,18 +324,29 @@ void register_handler_proc(unsigned int irq, struct irqaction *action)
void register_irq_proc(unsigned int irq, struct irq_desc *desc)
{
+ static DEFINE_MUTEX(register_lock);
char name [MAX_NAMELEN];
- if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip) || desc->dir)
+ if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
return;
+ /*
+ * irq directories are registered only when a handler is
+ * added, not when the descriptor is created, so multiple
+ * tasks might try to register at the same time.
+ */
+ mutex_lock(&register_lock);
+
+ if (desc->dir)
+ goto out_unlock;
+
memset(name, 0, MAX_NAMELEN);
sprintf(name, "%d", irq);
/* create /proc/irq/1234 */
desc->dir = proc_mkdir(name, root_irq_dir);
if (!desc->dir)
- return;
+ goto out_unlock;
#ifdef CONFIG_SMP
/* create /proc/irq/<irq>/smp_affinity */
@@ -355,6 +367,9 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc)
proc_create_data("spurious", 0444, desc->dir,
&irq_spurious_proc_fops, (void *)(long)irq);
+
+out_unlock:
+ mutex_unlock(&register_lock);
}
void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)