4.9-stable review patch. If anyone has any objections, please let me know.
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From: Alexandre Belloni alexandre.belloni@bootlin.com
[ Upstream commit b3a5ac42ab18b7d1a8f2f072ca0ee76a3b754a43 ]
On 32bit platforms, time_t is still a signed 32bit long. If it is overflowed, userspace and the kernel cant agree on the current system time. This causes multiple issues, in particular with systemd: https://github.com/systemd/systemd/issues/1143
A good workaround is to simply avoid using hctosys which is something I greatly encourage as the time is better set by userspace.
However, many distribution enable it and use systemd which is rendering the system unusable in case the RTC holds a date after 2038 (and more so after 2106). Many drivers have workaround for this case and they should be eliminated so there is only one place left to fix when userspace is able to cope with dates after the 31bit overflow.
Acked-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/rtc/hctosys.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/drivers/rtc/hctosys.c +++ b/drivers/rtc/hctosys.c @@ -49,6 +49,11 @@ 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) + goto err_read; +#endif + err = do_settimeofday64(&tv64);
dev_info(rtc->dev.parent,