Comment 28 for bug 1754584

Boiled it down to a minimal async I/O reproducer as follows:

#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <libaio.h>
#include <fcntl.h>
#include <err.h>

io_context_t io_ctx;

void do_sync_io(struct iocb *iocb)
{
        struct io_event event;
        struct iocb *iocbs[] = { iocb };
        struct timespec ts = { 30, 0 };

        if (io_submit(io_ctx, 1, iocbs) != 1)
                err(1, "io_submit failed");
        if (io_getevents(io_ctx, 0, 1, &event, &ts) != 1)
                err(1, "io_getevents failed");
}

int main(void)
{
        char *buf;
        int rwfd, status = 0, res, page_size = getpagesize();
        struct iocb iocb;

        if (io_queue_init(1024, &io_ctx))
                err(1, "io_queue_init failed");
        rwfd = open("testfile", O_RDWR | O_CREAT);
        if (rwfd < 0)
                err(1, "open failed");
        if (ftruncate(rwfd, 512) < 0)
                err(1, "ftruncate failed");
        buf = mmap(0, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, rwfd, 0);
        if (buf == MAP_FAILED)
                err(1, "mmap failed");

        (void)io_prep_pwrite(&iocb, rwfd, buf, 512, 0);
        do_sync_io(&iocb);

        (void)io_prep_pread(&iocb, rwfd, buf, 512, 0);
        do_sync_io(&iocb);
}