io_uring/fdinfo: only print ->sq_array[] if it's there

If a ring is setup with IORING_SETUP_NO_SQARRAY, then we don't have
the SQ array. Don't try to dump info from it through fdinfo if that
is the case.

Reported-by: syzbot+216e2ea6e0bf4a0acdd7@syzkaller.appspotmail.com
Fixes: 2af89ab ("io_uring: add option to remove SQ indirection")
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: axboe

io_uring/fdinfo.c

@@ -93,6 +93,8 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
 		struct io_uring_sqe *sqe;
 		unsigned int sq_idx;
 
+		if (ctx->flags & IORING_SETUP_NO_SQARRAY)
+			break;
 		sq_idx = READ_ONCE(ctx->sq_array[entry & sq_mask]);
 		if (sq_idx > sq_mask)
 			continue;