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SubjectRe: [PATCH v2] seqlock: mark raw_read_seqcount and read_seqcount_retry as __always_inline
On Sun, 23 Jun 2019 at 13:16, Thomas Gleixner <tglx@linutronix.de> wrote:
>
> On Tue, 11 Jun 2019, Anders Roxell wrote:
>
> > With the function graph tracer, each traced function calls sched_clock()
> > to take a timestamp. As sched_clock() uses
> > raw_read_seqcount()/read_seqcount_retry(), we must ensure that these
> > do not in turn trigger the graph tracer.
> > Both functions is marked as inline. However, if CONFIG_OPTIMIZE_INLINING
> > is set that may make the two functions tracable which they shouldn't.
> >
> > Rework so that functions raw_read_seqcount and read_seqcount_retry are
> > marked with __always_inline so they will be inlined even if
> > CONFIG_OPTIMIZE_INLINING is turned on.
>
> Why just those two? The same issue can happen in other places with other
> clocks which can be utilized by the tracer.
>
> Aside of your particular issue, there is no reason why any of those
> functions should ever trigger a graph.


Yes you are correct. I'll update the patch with __always_inline to all functions
in that file.

Cheers,
Anders

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