Hello,
Etienne Brateau, le dim. 01 mars 2026 16:43:40 +0100, a ecrit:
> void *func(void * a) {
> // printf("start\n");
> // fflush(stdout);
> for (int i = 0; i < 9; i++) {
> printf("out: %i\n", i);
> //printf("out\n");
> fflush(stdout);
> }
> }
>
> int main() {
>
> pthread_t a[9];
>
> for (int i = 0; i < 9; i++) {
> pthread_create(&a[i], NULL, func, NULL);
> }
>
> for (int i = 0; i < 9; i++) {
> pthread_join(a[i], NULL);
> }
>
> return 0;
> }
> ===
>
> Basically this program should output 81 lines (9 threads printing 9 lines),
> but
> it actually print less. (I usually do `./a.out | wc -l`)
Oh, god...
We have been missing libio-safety since glibc 2.26 because somebody
optimized it away for single-threaded programs without taking care that
htl would also need the _IO_enable_locks call...
I have pushed a fix to upstream and debian.
I'll upload fixed glibcs, since it's so grave a bug.
Thanks for the simple testcase!
Samuel
