Commit 56567a20 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'io_uring-6.6-2023-10-27' of git://git.kernel.dk/linux 

Pull io_uring fixes from Jens Axboe:
 "Fix for an issue reported where reading fdinfo could find a NULL
  thread as we didn't properly synchronize, and then a disable for the
  IOCB_DIO_CALLER_COMP optimization as a recent reported highlighted how
  that could lead to deadlocks if the task issued async O_DIRECT writes
  and then proceeded to do sync fallocate() calls"

* tag 'io_uring-6.6-2023-10-27' of git://git.kernel.dk/linux:
  io_uring/rw: disable IOCB_DIO_CALLER_COMP
  io_uring/fdinfo: lock SQ thread while retrieving thread cpu/pid
parents 2dc4e0f4 838b35bb

io_uring/fdinfo.c

+12 −6
Original line number Diff line number Diff line
@@ -53,7 +53,6 @@ static __cold int io_uring_show_cred(struct seq_file *m, unsigned int id, 
__cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f)

{

	struct io_ring_ctx *ctx = f->private_data;

	struct io_sq_data *sq = NULL;

	struct io_overflow_cqe *ocqe;

	struct io_rings *r = ctx->rings;

	unsigned int sq_mask = ctx->sq_entries - 1, cq_mask = ctx->cq_entries - 1;
@@ -64,6 +63,7 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f) 
	unsigned int cq_shift = 0;

	unsigned int sq_shift = 0;

	unsigned int sq_entries, cq_entries;

	int sq_pid = -1, sq_cpu = -1;

	bool has_lock;

	unsigned int i;
@@ -143,13 +143,19 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f) 
	has_lock = mutex_trylock(&ctx->uring_lock);



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

		sq = ctx->sq_data;

		if (!sq->thread)

			sq = NULL;

		struct io_sq_data *sq = ctx->sq_data;



		if (mutex_trylock(&sq->lock)) {

			if (sq->thread) {

				sq_pid = task_pid_nr(sq->thread);

				sq_cpu = task_cpu(sq->thread);

			}

			mutex_unlock(&sq->lock);

		}

	}



	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);

	seq_printf(m, "SqThread:\t%d\n", sq_pid);

	seq_printf(m, "SqThreadCpu:\t%d\n", sq_cpu);

	seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);

	for (i = 0; has_lock && i < ctx->nr_user_files; i++) {

		struct file *f = io_file_from_index(&ctx->file_table, i);

io_uring/rw.c

+0 −9
Original line number Diff line number Diff line
@@ -913,15 +913,6 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags) 
		kiocb_start_write(kiocb);

	kiocb->ki_flags |= IOCB_WRITE;



	/*

	 * For non-polled IO, set IOCB_DIO_CALLER_COMP, stating that our handler

	 * groks deferring the completion to task context. This isn't

	 * necessary and useful for polled IO as that can always complete

	 * directly.

	 */

	if (!(kiocb->ki_flags & IOCB_HIPRI))

		kiocb->ki_flags |= IOCB_DIO_CALLER_COMP;



	if (likely(req->file->f_op->write_iter))

		ret2 = call_write_iter(req->file, kiocb, &s->iter);

	else if (req->file->f_op->write)