From 7ce9a992ffde8ce93d5ae5767362a5c7389ae895 Mon Sep 17 00:00:00 2001
From: "Maciej W. Rozycki" <macro@linux-mips.org>
Date: Mon, 5 Nov 2018 03:48:25 +0000
Subject: [PATCH] rtc: hctosys: Add missing range error reporting
Git-commit: 7ce9a992ffde8ce93d5ae5767362a5c7389ae895
Patch-mainline: v4.20-rc3
References: bsc#1051510

Fix an issue with the 32-bit range error path in `rtc_hctosys' where no
error code is set and consequently the successful preceding call result
from `rtc_read_time' is propagated to `rtc_hctosys_ret'.  This in turn
makes any subsequent call to `hctosys_show' incorrectly report in sysfs
that the system time has been set from this RTC while it has not.

Set the error to ERANGE then if we can't express the result due to an
overflow.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Fixes: b3a5ac42ab18 ("rtc: hctosys: Ensure system time doesn't overflow time_t")
Cc: stable@vger.kernel.org # 4.17+
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/rtc/hctosys.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/hctosys.c b/drivers/rtc/hctosys.c
index e79f2a181ad2..b9ec4a16db1f 100644
--- a/drivers/rtc/hctosys.c
+++ b/drivers/rtc/hctosys.c
@@ -50,8 +50,10 @@ static int __init rtc_hctosys(void)
 	tv64.tv_sec = rtc_tm_to_time64(&tm);
 
 #if BITS_PER_LONG == 32
-	if (tv64.tv_sec > INT_MAX)
+	if (tv64.tv_sec > INT_MAX) {
+		err = -ERANGE;
 		goto err_read;
+	}
 #endif
 
 	err = do_settimeofday64(&tv64);
-- 
2.19.2