[PATCH] oprofile: fix potential deadlock on oprofilefs_lock

nmi_cpu_setup() is called from hardirq context and acquires oprofilefs_lock. alloc_event_buffer() and oprofilefs_ulong_from_user() acquire this lock without disabling irqs, which could deadlock. Signed-off-by: Jiri Kosina <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
huntrar · Mar 28, 2007 · 4dfc896 · 4dfc896
1 parent 6faee84
commit 4dfc896
Show file tree

Hide file tree

Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/drivers/oprofile/event_buffer.c b/drivers/oprofile/event_buffer.c
@@ -70,11 +70,12 @@ void wake_up_buffer_waiter(void)
 int alloc_event_buffer(void)
 {
 	int err = -ENOMEM;
+	unsigned long flags;
 
-	spin_lock(&oprofilefs_lock);
+	spin_lock_irqsave(&oprofilefs_lock, flags);
 	buffer_size = fs_buffer_size;
 	buffer_watershed = fs_buffer_watershed;
-	spin_unlock(&oprofilefs_lock);
+	spin_unlock_irqrestore(&oprofilefs_lock, flags);
 
 	if (buffer_watershed >= buffer_size)
 		return -EINVAL;

diff --git a/drivers/oprofile/oprofilefs.c b/drivers/oprofile/oprofilefs.c
@@ -65,6 +65,7 @@ ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user * buf, size_t co
 int oprofilefs_ulong_from_user(unsigned long * val, char const __user * buf, size_t count)
 {
 	char tmpbuf[TMPBUFSIZE];
+	unsigned long flags;
 
 	if (!count)
 		return 0;
@@ -77,9 +78,9 @@ int oprofilefs_ulong_from_user(unsigned long * val, char const __user * buf, siz
 	if (copy_from_user(tmpbuf, buf, count))
 		return -EFAULT;
 
-	spin_lock(&oprofilefs_lock);
+	spin_lock_irqsave(&oprofilefs_lock, flags);
 	*val = simple_strtoul(tmpbuf, NULL, 0);
-	spin_unlock(&oprofilefs_lock);
+	spin_unlock_irqrestore(&oprofilefs_lock, flags);
 	return 0;
 }