From: Pavel Begunkov <asml.silence@gmail.com> stable inclusion from stable-5.10.50 commit a75457f63086500d0182c0cb664e2e35d85d5dab bugzilla: 174522 https://gitee.com/openeuler/kernel/issues/I4DNFY Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- 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/d60270856b8a4560a639ef5f76e55eb563633599.162323645... Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- fs/io_uring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 72d1a34e1a35..fb63cc8f476d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2771,7 +2771,7 @@ static bool io_file_supports_async(struct file *file, int rw) 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) && -- 2.20.1