kernel/linux.git/drivers/rtc, branch v4.4.171

rtc: snvs: Add timeouts to avoid kernel lockups

2018-12-21T13:09:53+00:00

[ Upstream commit cd7f3a249dbed2858e6c2f30e5be7f1f7a709ee2 ] In order to read correctly from asynchronously updated RTC registers, it's necessary to read repeatedly until their values do not change from read to read. It's also necessary to wait for three RTC clock ticks for certain operations. There are no timeouts in this code and these operations could possibly loop forever. To avoid kernel hangs, put in timeouts. The iMX7d can be configured to stop the SRTC on a tamper event, which will lockup the kernel inside this driver as described above. These hangs can happen when running under qemu, which doesn't emulate the SNVS RTC, though currently the driver will refuse to load on qemu due to a timeout in the driver probe method. It could also happen if the SRTC block where somehow placed into reset or the slow speed clock that drives the SRTC counter (but not the CPU) were to stop. The symptoms on a two core iMX7d are a work queue hang on rtc_timer_do_work(), which eventually blocks a systemd fsnotify operation that triggers a work queue flush, causing systemd to hang and thus causing all services that should be started by systemd, like a console getty, to fail to start or stop. Also optimize the wait code to wait less. It only needs to wait for the clock to advance three ticks, not to see it change three times. Cc: Alexandre Belloni Cc: Alessandro Zummo Cc: Fabio Estevam Cc: Shawn Guo Cc: Bryan O'Donoghue Signed-off-by: Trent Piepho Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin

rtc: snvs: add a missing write sync

2018-12-21T13:09:53+00:00

[ Upstream commit 7bb633b1a9812a6b9f3e49d0cf17f60a633914e5 ] The clear of the LPTA_EN flag should be synced before writing to the alarm register. Omitting this synchronization creates a race when trying to change existing alarm. Signed-off-by: Guy Shapiro Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin

rtc: hctosys: Add missing range error reporting

2018-11-21T08:27:44+00:00

commit 7ce9a992ffde8ce93d5ae5767362a5c7389ae895 upstream. 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 Fixes: b3a5ac42ab18 ("rtc: hctosys: Ensure system time doesn't overflow time_t") Cc: stable@vger.kernel.org # 4.17+ Signed-off-by: Alexandre Belloni Signed-off-by: Greg Kroah-Hartman

rtc: bq4802: add error handling for devm_ioremap

2018-09-26T06:35:09+00:00

[ Upstream commit 7874b919866ba91bac253fa219d3d4c82bb944df ] When devm_ioremap fails, the lack of error-handling code may cause unexpected results. This patch adds error-handling code after calling devm_ioremap. Signed-off-by: Zhouyang Jia Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

rtc: ensure rtc_set_alarm fails when alarms are not supported

2018-08-06T14:24:30+00:00

[ Upstream commit abfdff44bc38e9e2ef7929f633fb8462632299d4 ] When using RTC_ALM_SET or RTC_WKALM_SET with rtc_wkalrm.enabled not set, rtc_timer_enqueue() is not called and rtc_set_alarm() may succeed but the subsequent RTC_AIE_ON ioctl will fail. RTC_ALM_READ would also fail in that case. Ensure rtc_set_alarm() fails when alarms are not supported to avoid letting programs think the alarms are working for a particular RTC when they are not. Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

rtc: tx4939: avoid unintended sign extension on a 24 bit shift

2018-05-30T05:49:14+00:00

[ Upstream commit 347876ad47b9923ce26e686173bbf46581802ffa ] The shifting of buf[5] by 24 bits to the left will be promoted to a 32 bit signed int and then sign-extended to an unsigned long. If the top bit of buf[5] is set then all then all the upper bits sec end up as also being set because of the sign-extension. Fix this by casting buf[5] to an unsigned long before the shift. Detected by CoverityScan, CID#1465292 ("Unintended sign extension") Fixes: 0e1492330cd2 ("rtc: add rtc-tx4939 driver") Signed-off-by: Colin Ian King Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

rtc: hctosys: Ensure system time doesn't overflow time_t

2018-05-30T05:49:10+00:00

[ 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 Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

rtc: snvs: Fix usage of snvs_rtc_enable

2018-05-30T05:49:09+00:00

[ Upstream commit 1485991c024603b2fb4ae77beb7a0d741128a48e ] commit 179a502f8c46 ("rtc: snvs: add Freescale rtc-snvs driver") introduces the SNVS RTC driver with a function snvs_rtc_enable(). snvs_rtc_enable() can return an error on the enable path however this driver does not currently trap that failure on the probe() path and consequently if enabling the RTC fails we encounter a later error spinning forever in rtc_write_sync_lp(). [ 36.093481] [] (__irq_svc) from [] (_raw_spin_unlock_irqrestore+0x34/0x44) [ 36.102122] [] (_raw_spin_unlock_irqrestore) from [] (regmap_read+0x4c/0x5c) [ 36.110938] [] (regmap_read) from [] (rtc_write_sync_lp+0x6c/0x98) [ 36.118881] [] (rtc_write_sync_lp) from [] (snvs_rtc_alarm_irq_enable+0x40/0x4c) [ 36.128041] [] (snvs_rtc_alarm_irq_enable) from [] (rtc_timer_do_work+0xd8/0x1a8) [ 36.137291] [] (rtc_timer_do_work) from [] (process_one_work+0x28c/0x76c) [ 36.145840] [] (process_one_work) from [] (worker_thread+0x34/0x58c) [ 36.153961] [] (worker_thread) from [] (kthread+0x138/0x150) [ 36.161388] [] (kthread) from [] (ret_from_fork+0x14/0x20) [ 36.168635] rcu_sched kthread starved for 2602 jiffies! g496 c495 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0 [ 36.178564] rcu_sched R running task 0 8 2 0x00000000 [ 36.185664] [] (__schedule) from [] (schedule+0x3c/0xa0) [ 36.192739] [] (schedule) from [] (schedule_timeout+0x78/0x4e0) [ 36.200422] [] (schedule_timeout) from [] (rcu_gp_kthread+0x648/0x1864) [ 36.208800] [] (rcu_gp_kthread) from [] (kthread+0x138/0x150) [ 36.216309] [] (kthread) from [] (ret_from_fork+0x14/0x20) This patch fixes by parsing the result of rtc_write_sync_lp() and propagating both in the probe and elsewhere. If the RTC doesn't start we don't proceed loading the driver and don't get into this loop mess later on. Fixes: 179a502f8c46 ("rtc: snvs: add Freescale rtc-snvs driver") Signed-off-by: Bryan O'Donoghue Acked-by: Shawn Guo Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

rtc: interface: Validate alarm-time before handling rollover

2018-04-13T17:50:15+00:00

[ Upstream commit da96aea0ed177105cb13ee83b328f6c61e061d3f ] In function __rtc_read_alarm() its possible for an alarm time-stamp to be invalid even after replacing missing components with current time-stamp. The condition 'alarm->time.tm_year < 70' will trigger this case and will cause the call to 'rtc_tm_to_time64(&alarm->time)' return a negative value for variable t_alm. While handling alarm rollover this negative t_alm (assumed to seconds offset from '1970-01-01 00:00:00') is converted back to rtc_time via rtc_time64_to_tm() which results in this error log with seemingly garbage values: "rtc rtc0: invalid alarm value: -2-1--1041528741 2005511117:71582844:32" This error was generated when the rtc driver (rtc-opal in this case) returned an alarm time-stamp of '00-00-00 00:00:00' to indicate that the alarm is disabled. Though I have submitted a separate fix for the rtc-opal driver, this issue may potentially impact other existing/future rtc drivers. To fix this issue the patch validates the alarm time-stamp just after filling up the missing datetime components and if rtc_valid_tm() still reports it to be invalid then bails out of the function without handling the rollover. Reported-by: Steve Best Signed-off-by: Vaibhav Jain Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

rtc: opal: Handle disabled TPO in opal_get_tpo_time()

2018-04-13T17:50:15+00:00

[ Upstream commit 6dc1cf6f932bb0ea4d8f5e913a0a401ecacd2f03 ] On PowerNV platform when Timed-Power-On(TPO) is disabled, read of stored TPO yields value with all date components set to '0' inside opal_get_tpo_time(). The function opal_to_tm() then converts it to an offset from year 1900 yielding alarm-time == "1900-00-01 00:00:00". This causes problems with __rtc_read_alarm() that expecting an offset from "1970-00-01 00:00:00" and returned alarm-time results in a -ve value for time64_t. Which ultimately results in this error reported in kernel logs with a seemingly garbage value: "rtc rtc0: invalid alarm value: -2-1--1041528741 2005511117:71582844:32" We fix this by explicitly handling the case of all alarm date-time components being '0' inside opal_get_tpo_time() and returning -ENOENT in such a case. This signals generic rtc that no alarm is set and it bails out from the alarm initialization flow without reporting the above error. Signed-off-by: Vaibhav Jain Reported-by: Steve Best Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman