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.
>
> /* 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.
--
Petri Latvala
> }
> --
> 2.32.0
>
