Commit 5f3f26f9 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: fix SQPOLL thread handling over exec 



Just like the changes for io-wq, ensure that we re-fork the SQPOLL
thread if the owner execs. Mark the ctx sq thread as sqo_exec if
it dies, and the ring as needing a wakeup which will force the task
to enter the kernel. When it does, setup the new thread and proceed
as usual.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 4fb6ac32

fs/io_uring.c

+34 −1
Original line number Diff line number Diff line
@@ -339,6 +339,7 @@ struct io_ring_ctx { 
		unsigned int		eventfd_async: 1;

		unsigned int		restricted: 1;

		unsigned int		sqo_dead: 1;

		unsigned int		sqo_exec: 1;



		/*

		 * Ring buffer of indices into array of io_uring_sqe, which is
@@ -6796,6 +6797,10 @@ static int io_sq_thread(void *data) 
	complete_all(&sqd->completion);

	mutex_lock(&sqd->lock);

	sqd->thread = NULL;

	list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {

		ctx->sqo_exec = 1;

		io_ring_set_wakeup_flag(ctx);

	}

	mutex_unlock(&sqd->lock);



	complete(&sqd->exited);
@@ -7840,6 +7845,25 @@ void __io_uring_free(struct task_struct *tsk) 
	tsk->io_uring = NULL;

}



static int io_sq_thread_fork(struct io_sq_data *sqd, struct io_ring_ctx *ctx)

{

	int ret;



	clear_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);

	reinit_completion(&sqd->completion);

	ctx->sqo_dead = ctx->sqo_exec = 0;

	sqd->task_pid = current->pid;

	current->flags |= PF_IO_WORKER;

	ret = io_wq_fork_thread(io_sq_thread, sqd);

	current->flags &= ~PF_IO_WORKER;

	if (ret < 0) {

		sqd->thread = NULL;

		return ret;

	}

	wait_for_completion(&sqd->completion);

	return io_uring_alloc_task_context(sqd->thread, ctx);

}



static int io_sq_offload_create(struct io_ring_ctx *ctx,

				struct io_uring_params *p)

{
@@ -9128,6 +9152,12 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, 
	if (ctx->flags & IORING_SETUP_SQPOLL) {

		io_cqring_overflow_flush(ctx, false, NULL, NULL);



		if (unlikely(ctx->sqo_exec)) {

			ret = io_sq_thread_fork(ctx->sq_data, ctx);

			if (ret)

				goto out;

			ctx->sqo_exec = 0;

		}

		ret = -EOWNERDEAD;

		if (unlikely(ctx->sqo_dead))

			goto out;
@@ -9229,8 +9259,11 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) 
	 */

	has_lock = mutex_trylock(&ctx->uring_lock);



	if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL))

	if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL)) {

		sq = ctx->sq_data;

		if (!sq->thread)

			sq = NULL;

	}



	seq_printf(m, "SqThread:\t%d\n", sq ? task_pid_nr(sq->thread) : -1);

	seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);