[PATCH 5.16 0928/1017] rtc: check if __rtc_read_time was successful

Greg Kroah-Hartman
2022-04-05T13:37:53Z

From: Tom Rix <trix@redhat.com>

commit 915593a7a663b2ad08b895a5f3ba8b19d89d4ebf upstream.

Clang static analysis reports this issue
interface.c:810:8: warning: Passed-by-value struct
argument contains uninitialized data
now = rtc_tm_to_ktime(tm);
^~~~~~~~~~~~~~~~~~~

tm is set by a successful call to __rtc_read_time()
but its return status is not checked. Check if
it was successful before setting the enabled flag.
Move the decl of err to function scope.

Fixes: 2b2f5ff00f63 ("rtc: interface: ignore expired timers when enqueuing new timers")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220326194236.2916310-1-trix@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/rtc/interface.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -804,9 +804,13 @@ static int rtc_timer_enqueue(struct rtc_
struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
struct rtc_time tm;
ktime_t now;
+ int err;
+
+ err = __rtc_read_time(rtc, &tm);
+ if (err)
+ return err;

timer->enabled = 1;
- __rtc_read_time(rtc, &tm);
now = rtc_tm_to_ktime(tm);

/* Skip over expired timers */
@@ -820,7 +824,6 @@ static int rtc_timer_enqueue(struct rtc_
trace_rtc_timer_enqueue(timer);
if (!next || ktime_before(timer->node.expires, next->expires)) {
struct rtc_wkalrm alarm;
- int err;

alarm.time = rtc_ktime_to_tm(timer->node.expires);
alarm.enabled = 1;