Hi
Sorry for the long delay.
> char *get_task_comm(char *buf, struct task_struct *tsk)
> {
> - /* buf must be at least sizeof(tsk->comm) in size */
> - task_lock(tsk);
> - strncpy(buf, tsk->comm, sizeof(tsk->comm));
> - task_unlock(tsk);
> + unsigned long seq;
> +
> + do {
> + seq = read_seqbegin(&tsk->comm_lock);
> +
> + strncpy(buf, tsk->comm, sizeof(tsk->comm));
> +
> + } while (read_seqretry(&tsk->comm_lock, seq));
> +
> return buf;
> }
Can you please explain why we should use seqlock? That said,
we didn't use seqlock for /proc items. because, plenty seqlock
write may makes readers busy wait. Then, if we don't have another
protection, we give the local DoS attack way to attackers.
task->comm is used for very fundamentally. then, I doubt we can
assume write is enough rare. Why can't we use normal spinlock?
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