| From 976517f162a05f4315b2373fd11585c395506259 Mon Sep 17 00:00:00 2001 |
| From: Pavel Begunkov <asml.silence@gmail.com> |
| Date: Wed, 9 Jun 2021 12:07:25 +0100 |
| Subject: io_uring: fix blocking inline submission |
| |
| From: Pavel Begunkov <asml.silence@gmail.com> |
| |
| commit 976517f162a05f4315b2373fd11585c395506259 upstream. |
| |
| There is a complaint against sys_io_uring_enter() blocking if it submits |
| stdin reads. The problem is in __io_file_supports_async(), which |
| sees that it's a cdev and allows it to be processed inline. |
| |
| Punt char devices using generic rules of io_file_supports_async(), |
| including checking for presence of *_iter() versions of rw callbacks. |
| Apparently, it will affect most of cdevs with some exceptions like |
| null and zero devices. |
| |
| Cc: stable@vger.kernel.org |
| Reported-by: Birk Hirdman <lonjil@gmail.com> |
| Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> |
| Link: https://lore.kernel.org/r/d60270856b8a4560a639ef5f76e55eb563633599.1623236455.git.asml.silence@gmail.com |
| Signed-off-by: Jens Axboe <axboe@kernel.dk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/io_uring.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/fs/io_uring.c |
| +++ b/fs/io_uring.c |
| @@ -2770,7 +2770,7 @@ static bool io_file_supports_async(struc |
| return true; |
| return false; |
| } |
| - if (S_ISCHR(mode) || S_ISSOCK(mode)) |
| + if (S_ISSOCK(mode)) |
| return true; |
| if (S_ISREG(mode)) { |
| if (io_bdev_nowait(file->f_inode->i_sb->s_bdev) && |
