On Fri, Nov 19, 2021 at 03:34:54PM +0000, Tvrtko Ursulin wrote:
>
> On 19/11/2021 13:53, Petri Latvala wrote:
> > On Fri, Nov 19, 2021 at 12:59:42PM +0000, Tvrtko Ursulin wrote:
> > > From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> > >
> > > .../lib/igt_thread.c: In function ‘__igt_unique____igt_constructor_l66’:
> > > .../lib/igt_thread.c:68:9: warning: ‘pthread_setspecific’ expecting 1 byte in a region of size 0 [-Wstringop-overread]
> > > 68 | pthread_setspecific(__igt_is_main_thread, (void*) 0x1);
> > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >
> > > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> > > Cc: Petri Latvala <petri.latvala@xxxxxxxxx>
> > > ---
> > > lib/igt_core.c | 6 ++++--
> > > lib/igt_thread.c | 4 +++-
> > > 2 files changed, 7 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/lib/igt_core.c b/lib/igt_core.c
> > > index ec05535cd56e..acb9743c4a24 100644
> > > --- a/lib/igt_core.c
> > > +++ b/lib/igt_core.c
> > > @@ -2752,6 +2752,8 @@ void igt_vlog(const char *domain, enum igt_log_level level, const char *format,
> > > char *line, *formatted_line;
> > > char *thread_id;
> > > const char *program_name;
> > > + const uintptr_t false_key = 0;
> > > + const uintptr_t true_key = 1;
> > > const char *igt_log_level_str[] = {
> > > "DEBUG",
> > > "INFO",
> > > @@ -2796,9 +2798,9 @@ void igt_vlog(const char *domain, enum igt_log_level level, const char *format,
> > > }
> > > if (line[strlen(line) - 1] == '\n')
> > > - pthread_setspecific(__vlog_line_continuation, (void*) false);
> > > + pthread_setspecific(__vlog_line_continuation, &false_key);
> > > else
> > > - pthread_setspecific(__vlog_line_continuation, (void*) true);
> > > + pthread_setspecific(__vlog_line_continuation, &true_key);
> >
> > Quoting the usage of this:
> > if (pthread_getspecific(__vlog_line_continuation)) {
> >
> > That's going to give a non-null pointer in both cases.
>
> Doh..
>
> >
> >
> >
> > > /* append log buffer */
> > > _igt_log_buffer_append(formatted_line);
> > > diff --git a/lib/igt_thread.c b/lib/igt_thread.c
> > > index 5bdda4102def..f5de2d57eaaa 100644
> > > --- a/lib/igt_thread.c
> > > +++ b/lib/igt_thread.c
> > > @@ -64,6 +64,8 @@ bool igt_thread_is_main(void)
> > > }
> > > igt_constructor {
> > > + const uintptr_t key = 1;
> > > +
> > > pthread_key_create(&__igt_is_main_thread, NULL);
> > > - pthread_setspecific(__igt_is_main_thread, (void*) 0x1);
> > > + pthread_setspecific(__igt_is_main_thread, &key);
> >
> > This is fine, __igt_is_main_thread key will have non-null only on the
> > main thread. But still a bit sus slapping the address of a
> > function-local variable to setspecific, we might just be trading a
> > compiler warning for a new future one.
>
> And this is then the same - why do you say this one is okay? :)
Because setspecific for this key is called from only one thread so it
kinda works.
--
Petri Latvala
>
> Okay I wasn't sufficiently focused while trying to fix this. No idea then
> apart for playing with pragmas.
>
> Regards,
>
> Tvrtko
