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Subject[patch] goldfish: locking bugs in goldfish_pipe_read_write()
We recently messed up the error handling here.  We can return with the
pipe->lock held or sometimes we unlock twice by mistake.

Fixes: 2f3be88237a3 ('goldfish_pipe: Pin pages to memory while copying and other cleanups')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index e3fab9a..839df4a 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -313,7 +313,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
!is_write, 0, &page, NULL);
up_read(&current->mm->mmap_sem);
if (ret < 0)
- return ret;
+ break;

if (dev->version) {
/* Device version 1 or newer (qemu-android) expects the
@@ -400,22 +400,16 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
while (test_bit(wakeBit, &pipe->flags)) {
if (wait_event_interruptible(
pipe->wake_queue,
- !test_bit(wakeBit, &pipe->flags))) {
- ret = -ERESTARTSYS;
- break;
- }
-
- if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)) {
- ret = -EIO;
- break;
- }
+ !test_bit(wakeBit, &pipe->flags)))
+ return -ERESTARTSYS;
+
+ if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
+ return -EIO;
}

/* Try to re-acquire the lock */
- if (mutex_lock_interruptible(&pipe->lock)) {
- ret = -ERESTARTSYS;
- break;
- }
+ if (mutex_lock_interruptible(&pipe->lock))
+ return -ERESTARTSYS;
}
mutex_unlock(&pipe->lock);

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