Messages in this thread | ![/](/images/icornerl.gif) | | From | Chen-Yu Tsai <> | Date | Tue, 26 Jul 2016 14:42:00 +0800 | Subject | Re: [PATCH] clocksource: sun4i: Clear interrupts after stopping timer in probe function |
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On Tue, Jul 26, 2016 at 1:49 PM, Maxime Ripard <maxime.ripard@free-electrons.com> wrote: > On Tue, Jul 26, 2016 at 11:01:59AM +0800, Chen-Yu Tsai wrote: >> The bootloader (U-boot) sometimes uses this timer for various delays. >> It uses it as a ongoing counter, and does comparisons on the current >> counter value. The timer counter is never stopped. >> >> In some cases when the user interacts with the bootloader, or lets >> it idle for some time before loading Linux, the timer may expire, >> and an interrupt will be pending. This results in an unexpected >> interrupt when the timer interrupt is enabled by the kernel, at >> which point the event_handler isn't set yet. This results in a NULL >> pointer dereference exception, panic, and no way to reboot. >> >> Clear any pending interrupts after we stop the timer in the probe >> function to avoid this. >> >> Signed-off-by: Chen-Yu Tsai <wens@csie.org> > > Awesome, thanks! > > You should put stable in Cc though for this kind of patches.
AFAIK some maintainers prefer to add it themselves. Not sure about clocksource so I left it out.
ChenYu
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