From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sedat Dilek <sedat.dilek@gmail.com>
Subject: Re: [PATCH] usbhid: Fix lockdep unannotated irqs-off warning
Date: Wed, 30 Sep 2015 12:39:58 +0200
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To: Steven Rostedt <rostedt@goodmis.org>
Cc: Jiri Kosina <jikos@kernel.org>, linux-input@vger.kernel.org, Tejun Heo <tj@kernel.org>, Lai Jiangshan <jiangshanlai@gmail.com>, Paul McKenney <paulmck@linux.vnet.ibm.com>

On Wed, Sep 30, 2015 at 12:13 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
> On Wed, 30 Sep 2015 11:46:31 +0200
> Sedat Dilek <sedat.dilek@gmail.com> wrote:
>
>> On Wed, Sep 30, 2015 at 10:56 AM, Steven Rostedt <rostedt@goodmis.org> wrote:
>> > On Wed, 30 Sep 2015 09:35:23 +0200 (CEST)
>> > Jiri Kosina <jikos@kernel.org> wrote:
>> >
>> >
>> >> [ ... snip a lot of stuff ... ]
>> >> > What shall I do... play with lockdep (print_irqtrace_events) in
>> >> > del_timer_sync()?
>> >
>> > Also, do you have PARAVIRT enabled by chance?
>> >
>>
>> Yes.
>>
>> CONFIG_PARAVIRT=y
>>
>> Is that the corresponding indicator in dmesg-log?
>>
>> [    0.000000] Booting paravirtualized kernel on bare hardware
>>
>> What is your suspicion, Lt. Columbo?
>>
>
> Heh, I loved that show.
>
> Can you see if you still have the issue if you disable that. PARAVIRT
> adds a bit of magic when run on baremetal. See
> arch/x86/kernel/alterative.c. On boot up, things like disabling
> interrupts, which are originally compiled to perform a function call,
> that on a virtual machine would do hypervisor calls into the host, and
> on baremetal does the real code. But that alterative.c file will do
> live patching of the code to not do the function call but instead do
> the real work in place (if it can).
>
> Something tells me that with clang, things are not as they're expected,
> and perhaps the modification isn't working.
>

LOL, there is a LLVM(Linux) bug reported in that area - that's why
arch_hweight() is disabled etc.
I have the bug-no not at hand.
I am not in front of my machine right now.

- sed@ CSI Tuebingen/Germany -