From 6b121dc6807cbc1d4ebc608e7c040e2de93ed3b7 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 23 Apr 2021 09:39:19 +0930 Subject: [PATCH] soc: aspeed: fix a ternary sign expansion bug [ Upstream commit 5ffa828534036348fa90fb3079ccc0972d202c4a ] The intent here was to return negative error codes but it actually returns positive values. The problem is that type promotion with ternary operations is quite complicated. "ret" is an int. "copied" is a u32. And the snoop_file_read() function returns long. What happens is that "ret" is cast to u32 and becomes positive then it's cast to long and it's still positive. Fix this by removing the ternary so that "ret" is type promoted directly to long. Fixes: 3772e5da4454 ("drivers/misc: Aspeed LPC snoop output using misc chardev") Signed-off-by: Dan Carpenter Signed-off-by: Joel Stanley Reviewed-by: Patrick Venture Link: https://lore.kernel.org/r/YIE90PSXsMTa2Y8n@mwanda Link: https://lore.kernel.org/r/20210423000919.1249474-1-joel@jms.id.au' Signed-off-by: Arnd Bergmann Signed-off-by: Sasha Levin --- drivers/soc/aspeed/aspeed-lpc-snoop.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/soc/aspeed/aspeed-lpc-snoop.c b/drivers/soc/aspeed/aspeed-lpc-snoop.c index dbe5325a324d..538d7aab8db5 100644 --- a/drivers/soc/aspeed/aspeed-lpc-snoop.c +++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c @@ -95,8 +95,10 @@ static ssize_t snoop_file_read(struct file *file, char __user *buffer, return -EINTR; } ret = kfifo_to_user(&chan->fifo, buffer, count, &copied); + if (ret) + return ret; - return ret ? ret : copied; + return copied; } static __poll_t snoop_file_poll(struct file *file,