Commit d3cac64c authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: fix NULL-mm for linked reqs 



__io_queue_sqe() tries to handle all request of a link,
so it's not enough to grab mm in io_sq_thread_acquire_mm()
based just on the head.

Don't check req->needs_mm and do it always.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
parent f6b6c7d6

fs/io_uring.c

+11 −4
Original line number Diff line number Diff line
@@ -1991,10 +1991,9 @@ static void io_sq_thread_drop_mm(struct io_ring_ctx *ctx) 
	}

}



static int io_sq_thread_acquire_mm(struct io_ring_ctx *ctx,

				   struct io_kiocb *req)

static int __io_sq_thread_acquire_mm(struct io_ring_ctx *ctx)

{

	if (io_op_defs[req->opcode].needs_mm && !current->mm) {

	if (!current->mm) {

		if (unlikely(!mmget_not_zero(ctx->sqo_mm)))

			return -EFAULT;

		kthread_use_mm(ctx->sqo_mm);
@@ -2003,6 +2002,14 @@ static int io_sq_thread_acquire_mm(struct io_ring_ctx *ctx, 
	return 0;

}



static int io_sq_thread_acquire_mm(struct io_ring_ctx *ctx,

				   struct io_kiocb *req)

{

	if (!io_op_defs[req->opcode].needs_mm)

		return 0;

	return __io_sq_thread_acquire_mm(ctx);

}



#ifdef CONFIG_BLOCK

static bool io_resubmit_prep(struct io_kiocb *req, int error)

{
@@ -2781,7 +2788,7 @@ static void io_async_buf_retry(struct callback_head *cb) 
	ctx = req->ctx;



	__set_current_state(TASK_RUNNING);

	if (!io_sq_thread_acquire_mm(ctx, req)) {

	if (!__io_sq_thread_acquire_mm(ctx)) {

		mutex_lock(&ctx->uring_lock);

		__io_queue_sqe(req, NULL);

		mutex_unlock(&ctx->uring_lock);

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