From: Joel Fernandes <joel@joelfernandes.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Zenghui Yu <yuzenghui@huawei.com>,
wanghaibin.wang@huawei.com, linux-trace-devel@vger.kernel.org
Subject: Re: [PATCH] tracepoint: fix bad trace value in trace_kvm_exit()
Date: Thu, 29 Nov 2018 18:18:42 -0800 [thread overview]
Message-ID: <20181130021842.GA104630@google.com> (raw)
In-Reply-To: <20181128213442.08e90ed4@vmware.local.home>
On Wed, Nov 28, 2018 at 09:34:42PM -0500, Steven Rostedt wrote:
> On Thu, 29 Nov 2018 10:21:55 +0800
> Zenghui Yu <yuzenghui@huawei.com> wrote:
>
> > On 2018/11/28 11:54, Steven Rostedt wrote:
> > > On Wed, 28 Nov 2018 03:35:23 +0000
> > > Zenghui Yu <yuzenghui@huawei.com> wrote:
> > >
> > >> After enabling KVM event tracing, almost all of trace_kvm_exit()'s
> > >> printk shows
> > >>
> > >> "kvm_exit: IRQ: ..."
> > >>
> > >> even if the actual exception_type is NOT IRQ. More specifically,
> > >> trace_kvm_exit() is defined in virt/kvm/arm/trace.h by TRACE_EVENT.
> > >>
> > >> This slight problem may have existed after commit e6753f23d961
> > >> ("tracepoint: Make rcuidle tracepoint callers use SRCU"). There are
> > >> two variables in trace_kvm_exit() and __DO_TRACE() which have the
> > >> same name, *idx*. Thus the actual value of *idx* will be overwritten
> > >> when tracing. Fix it by adding a simple prefix.
> > >
> > > Nice catch! I'll apply it tomorrow and start testing it then.
> >
> > Thanks Steven!
> >
>
> FYI, I renamed your subject to:
>
> tracepoint: Use __idx instead of idx in DO_TRACE macro to make it unique
>
> to make the name more specific to the fix and not the symptom.
>
> Thanks!
Thanks!
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
- Joel
prev parent reply other threads:[~2018-11-30 13:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 3:35 [PATCH] tracepoint: fix bad trace value in trace_kvm_exit() Zenghui Yu
2018-11-28 3:54 ` Steven Rostedt
2018-11-29 2:21 ` Zenghui Yu
2018-11-29 2:34 ` Steven Rostedt
2018-11-30 2:18 ` Joel Fernandes [this message]
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