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ANDROID: goldfish: goldfish_pipe: fix locking errors

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If the get_user_pages_fast() call in goldfish_pipe_read_write() failed,
it would return while still holding pipe->lock.

goldfish_pipe_read_write() later releases and tries to re-acquire
pipe->lock.  If the re-acquire call failed, goldfish_pipe_read_write()
would try unlock pipe->lock on exit anyway.

This fixes the smatch messages:

drivers/platform/goldfish/goldfish_pipe.c:392 goldfish_pipe_read_write() error: double unlock 'mutex:&pipe->lock'
drivers/platform/goldfish/goldfish_pipe.c:397 goldfish_pipe_read_write() warn: inconsistent returns 'mutex:&pipe->lock'.

Change-Id: Ifd06a76b32027ca451a001704ade0c5440ed69c4
Signed-off-by: Greg Hackmann <ghackmann@google.com>
This commit is contained in:
Greg Hackmann 2016-11-18 11:09:02 -08:00
parent 5f93f3cb3a
commit 37e461fc44
1 changed files with 4 additions and 4 deletions
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8
drivers/platform/goldfish/goldfish_pipe.c
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@ -273,11 +273,13 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
if (ret == 0) {
DPRINT("%s: error: (requested pages == 0) (wanted %d)\n",
__FUNCTION__, requested_pages);
mutex_unlock(&pipe->lock);
return ret;
}
if (ret < 0) {
DPRINT("%s: (requested pages < 0) %d \n",
__FUNCTION__, requested_pages);
mutex_unlock(&pipe->lock);
return ret;
}
@ -384,10 +386,8 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
}
/* 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);