1 files changed, 37 insertions, 31 deletions

diff --git a/kernel/kcov.c b/kernel/kcov.c
index 36ca640c4f8e..e1be7301500b 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -564,31 +564,12 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
 			     unsigned long arg)
 {
 	struct task_struct *t;
-	unsigned long size, unused;
+	unsigned long flags, unused;
 	int mode, i;
 	struct kcov_remote_arg *remote_arg;
 	struct kcov_remote *remote;
-	unsigned long flags;
 
 	switch (cmd) {
-	case KCOV_INIT_TRACE:
-		/*
-		 * Enable kcov in trace mode and setup buffer size.
-		 * Must happen before anything else.
-		 */
-		if (kcov->mode != KCOV_MODE_DISABLED)
-			return -EBUSY;
-		/*
-		 * Size must be at least 2 to hold current position and one PC.
-		 * Later we allocate size * sizeof(unsigned long) memory,
-		 * that must not overflow.
-		 */
-		size = arg;
-		if (size < 2 || size > INT_MAX / sizeof(unsigned long))
-			return -EINVAL;
-		kcov->size = size;
-		kcov->mode = KCOV_MODE_INIT;
-		return 0;
 	case KCOV_ENABLE:
 		/*
 		 * Enable coverage for the current task.
@@ -692,9 +673,32 @@ static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
 	struct kcov_remote_arg *remote_arg = NULL;
 	unsigned int remote_num_handles;
 	unsigned long remote_arg_size;
-	unsigned long flags;
+	unsigned long size, flags;
 
-	if (cmd == KCOV_REMOTE_ENABLE) {
+	kcov = filep->private_data;
+	switch (cmd) {
+	case KCOV_INIT_TRACE:
+		/*
+		 * Enable kcov in trace mode and setup buffer size.
+		 * Must happen before anything else.
+		 *
+		 * First check the size argument - it must be at least 2
+		 * to hold the current position and one PC. Later we allocate
+		 * size * sizeof(unsigned long) memory, that must not overflow.
+		 */
+		size = arg;
+		if (size < 2 || size > INT_MAX / sizeof(unsigned long))
+			return -EINVAL;
+		spin_lock_irqsave(&kcov->lock, flags);
+		if (kcov->mode != KCOV_MODE_DISABLED) {
+			spin_unlock_irqrestore(&kcov->lock, flags);
+			return -EBUSY;
+		}
+		kcov->size = size;
+		kcov->mode = KCOV_MODE_INIT;
+		spin_unlock_irqrestore(&kcov->lock, flags);
+		return 0;
+	case KCOV_REMOTE_ENABLE:
 		if (get_user(remote_num_handles, (unsigned __user *)(arg +
 				offsetof(struct kcov_remote_arg, num_handles))))
 			return -EFAULT;
@@ -710,16 +714,18 @@ static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
 			return -EINVAL;
 		}
 		arg = (unsigned long)remote_arg;
+		fallthrough;
+	default:
+		/*
+		 * All other commands can be normally executed under a spin lock, so we
+		 * obtain and release it here in order to simplify kcov_ioctl_locked().
+		 */
+		spin_lock_irqsave(&kcov->lock, flags);
+		res = kcov_ioctl_locked(kcov, cmd, arg);
+		spin_unlock_irqrestore(&kcov->lock, flags);
+		kfree(remote_arg);
+		return res;
 	}
-
-	kcov = filep->private_data;
-	spin_lock_irqsave(&kcov->lock, flags);
-	res = kcov_ioctl_locked(kcov, cmd, arg);
-	spin_unlock_irqrestore(&kcov->lock, flags);
-
-	kfree(remote_arg);
-
-	return res;
 }
 
 static const struct file_operations kcov_fops = {