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| author | Mateusz Jończyk <mat.jonczyk@o2.pl> | 2021-12-10 23:01:25 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-13 21:59:14 +0300 |
| commit | be6c3152d6f6d9c4a72eeb7126b762b413b1030c (patch) | |
| tree | fb03d4ac48752423d3c1107d9c3dcae32011509b /arch | |
| parent | 8c69210752228d141c6e690eda98945265902870 (diff) | |
| download | linux-be6c3152d6f6d9c4a72eeb7126b762b413b1030c.tar.xz | |
rtc: Check return value from mc146818_get_time()
[ Upstream commit 0dd8d6cb9eddfe637bcd821bbfd40ebd5a0737b9 ]
There are 4 users of mc146818_get_time() and none of them was checking
the return value from this function. Change this.
Print the appropriate warnings in callers of mc146818_get_time() instead
of in the function mc146818_get_time() itself, in order not to add
strings to rtc-mc146818-lib.c, which is kind of a library.
The callers of alpha_rtc_read_time() and cmos_read_time() may use the
contents of (struct rtc_time *) even when the functions return a failure
code. Therefore, set the contents of (struct rtc_time *) to 0x00,
which looks more sensible then 0xff and aligns with the (possibly
stale?) comment in cmos_read_time:
/*
* If pm_trace abused the RTC for storage, set the timespec to 0,
* which tells the caller that this RTC value is unusable.
*/
For consistency, do this in mc146818_get_time().
Note: hpet_rtc_interrupt() may call mc146818_get_time() many times a
second. It is very unlikely, though, that the RTC suddenly stops
working and mc146818_get_time() would consistently fail.
Only compile-tested on alpha.
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: linux-alpha@vger.kernel.org
Cc: x86@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210200131.153887-4-mat.jonczyk@o2.pl
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/alpha/kernel/rtc.c | 7 | ||||
| -rw-r--r-- | arch/x86/kernel/hpet.c | 8 |
2 files changed, 12 insertions, 3 deletions
diff --git a/arch/alpha/kernel/rtc.c b/arch/alpha/kernel/rtc.c index ce3077946e1d..fb3025396ac9 100644 --- a/arch/alpha/kernel/rtc.c +++ b/arch/alpha/kernel/rtc.c @@ -80,7 +80,12 @@ init_rtc_epoch(void) static int alpha_rtc_read_time(struct device *dev, struct rtc_time *tm) { - mc146818_get_time(tm); + int ret = mc146818_get_time(tm); + + if (ret < 0) { + dev_err_ratelimited(dev, "unable to read current time\n"); + return ret; + } /* Adjust for non-default epochs. It's easier to depend on the generic __get_rtc_time and adjust the epoch here than create diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index 882213df3713..71f336425e58 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -1435,8 +1435,12 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id) hpet_rtc_timer_reinit(); memset(&curr_time, 0, sizeof(struct rtc_time)); - if (hpet_rtc_flags & (RTC_UIE | RTC_AIE)) - mc146818_get_time(&curr_time); + if (hpet_rtc_flags & (RTC_UIE | RTC_AIE)) { + if (unlikely(mc146818_get_time(&curr_time) < 0)) { + pr_err_ratelimited("unable to read current time from RTC\n"); + return IRQ_HANDLED; + } + } if (hpet_rtc_flags & RTC_UIE && curr_time.tm_sec != hpet_prev_update_sec) { |