On 11 July 2014 17:30, Steven Rostedt <[email protected]> wrote:
> On Fri, 11 Jul 2014 08:12:40 -0700
> "Paul E. McKenney" <[email protected]> wrote:
>
>> On Fri, Jul 11, 2014 at 01:38:12PM +0200, Ard Biesheuvel wrote:
>> > Commit f7f7bac9cb1c ("rcu: Have the RCU tracepoints use the
>> > tracepoint_string
>> > infrastructure") unconditionally populates the __tracepoint_str input
>> > section,
>> > but this section is not assigned an output section if CONFIG_TRACING is
>> > not set.
>> > This results in the __tracepoint_str turning up in unexpected places, i.e.,
>> > after _edata.
>> >
>> > Signed-off-by: Ard Biesheuvel <[email protected]>
>> > Cc: [email protected]
>> > Cc: [email protected]
>> > Cc: [email protected]
>>
>> If you get a Reviewed-by from Steven Rostedt, I will be happy to queue
>> this one.
>
> I'm fine with it, but it should add a comment.
>
>
>>
>> Thanx, Paul
>>
>> > ---
>> > kernel/rcu/tree.c | 9 ++++++++-
>> > 1 file changed, 8 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
>> > index f1ba77363fbb..ac1984149eb5 100644
>> > --- a/kernel/rcu/tree.c
>> > +++ b/kernel/rcu/tree.c
>> > @@ -79,9 +79,16 @@ static struct lock_class_key
>> > rcu_fqs_class[RCU_NUM_LVLS];
>> > * the tracing userspace tools to be able to decipher the string
>> > * address to the matching string.
>> > */
>> > +#ifdef CONFIG_TRACING
>
> /*
> * When tracing is enabled, DEFINE_TPS() will export the string to
> * userspace via the tracing debugfs directory. This allows userspace
> * tools to read the binary tracepoints that reference the pointer
> * to the string and not the string itself.
> */
>
>
>> > +#define DEFINE_TPS(sname) \
>> > +static const char *tp_##sname##_varname __used __tracepoint_string =
>> > sname##_varname;
>> > +#else
>> > +#define DEFINE_TPS(sname)
>> > +#endif
>
> Also, perhaps we should call it:
>
> DEFINE_RCU_TPS()
>
> Other than that, I'm fine with the patch.
>
> I'll review v2 ;-)
>
Thanks gents, v2 coming up.
--
Ard.
>> > +
>> > #define RCU_STATE_INITIALIZER(sname, sabbr, cr) \
>> > static char sname##_varname[] = #sname; \
>> > -static const char *tp_##sname##_varname __used __tracepoint_string =
>> > sname##_varname; \
>> > +DEFINE_TPS(sname) \
>> > struct rcu_state sname##_state = { \
>> > .level = { &sname##_state.node[0] }, \
>> > .call = cr, \
>> > --
>> > 1.8.3.2
>> >
>
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