Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1469954

Re: [PATCH v3] clocksource: sun4i: Clear interrupts after stopping timer in probe function

Show all headers | View raw

[Multipart message — attachments visible in raw view] - view raw

On Thu, Aug 25, 2016 at 02:26:59PM +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.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>

Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v3] clocksource: sun4i: Clear interrupts after stopping timer in probe function Chen-Yu Tsai <wens@csie.org> - 2016-08-25 09:30 +0200
  Re: [PATCH v3] clocksource: sun4i: Clear interrupts after stopping  timer in probe function Maxime Ripard <maxime.ripard@free-electrons.com> - 2016-08-25 10:20 +0200
  Re: [PATCH v3] clocksource: sun4i: Clear interrupts after stopping  timer in probe function Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-08-25 11:20 +0200

csiph-web