linux-kernel - Re: [PATCH v2] kdb: use ktime_get_mono_fast_ns() instead of ktime_get

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Date:   Tue, 30 Jan 2018 08:02:10 -0600
From:   Jason Wessel <jason.wessel@...driver.com>
To:     Arnd Bergmann <arnd@...db.de>, Baolin Wang <baolin.wang@...aro.org>
CC:     Daniel Thompson <daniel.thompson@...aro.org>,
        Ingo Molnar <mingo@...nel.org>,
        Mark Brown <broonie@...nel.org>,
        <kgdb-bugreport@...ts.sourceforge.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] kdb: use ktime_get_mono_fast_ns() instead of
 ktime_get_ts()

On 01/30/2018 07:35 AM, Arnd Bergmann wrote:
> On Mon, Jan 29, 2018 at 3:22 AM, Baolin Wang <baolin.wang@...aro.org> wrote:
>> The kdb code will print the monotonic time by ktime_get_ts(), but
>> the ktime_get_ts() will be protected by a sequence lock, that will
>> introduce one deadlock risk if the lock was already held in the
>> context from which we entered the debugger.
>>
>> Thus we can use the ktime_get_mono_fast_ns() to get the monotonic
>> time, which is NMI safe access to clock monotonic. Moreover we can
>> remove the 'struct timespec', which is not y2038 safe.
>>
>> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
> 
> Reviewed-by: Arnd Bergmann <arnd@...db.de>
> 


I'll add this in today, run some tests and it should be in the merge window.

Thanks,
Jason