5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yongliang Gao <leonylgao@xxxxxxxxxxx>
[ Upstream commit e8ba8a2bc4f60a1065f23d6a0e7cbea945a0f40d ]
If the __rtc_read_time call fails,, the struct rtc_time tm; may contain
uninitialized data, or an illegal date/time read from the RTC hardware.
When calling rtc_tm_to_ktime later, the result may be a very large value
(possibly KTIME_MAX). If there are periodic timers in rtc->timerqueue,
they will continually expire, may causing kernel softlockup.
Fixes: 6610e0893b8b ("RTC: Rework RTC code to use timerqueue for events")
Signed-off-by: Yongliang Gao <leonylgao@xxxxxxxxxxx>
Acked-by: Jingqun Li <jingqunli@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20241011043153.3788112-1-leonylgao@xxxxxxxxx
Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/rtc/interface.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index d858cd819932f..1536d53a7af7f 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -894,13 +894,18 @@ void rtc_timer_do_work(struct work_struct *work)
struct timerqueue_node *next;
ktime_t now;
struct rtc_time tm;
+ int err;
struct rtc_device *rtc =
container_of(work, struct rtc_device, irqwork);
mutex_lock(&rtc->ops_lock);
again:
- __rtc_read_time(rtc, &tm);
+ err = __rtc_read_time(rtc, &tm);
+ if (err) {
+ mutex_unlock(&rtc->ops_lock);
+ return;
+ }
now = rtc_tm_to_ktime(tm);
while ((next = timerqueue_getnext(&rtc->timerqueue))) {
if (next->expires > now)
--
2.43.0
