We request non-blocking I/O in the generic implementation, but some files ‒ ttys ‒ only check O_NONBLOCK. Refuse them here, lest we risk sleeping with the pipe locked for indeterminate lengths of time. This also masks inconsistent wake-ups (usually every second line) when splicing from ttys in icanon mode. Regular files don't /have/ a distinct O_NONBLOCK mode, because they always behave non-blockingly, and for them FMODE_NOWAIT is used in the purest sense of /* File is capable of returning -EAGAIN if I/O will block */ which is not set by the vast majority of filesystems, and it's not the semantic we want here. Link: https://lore.kernel.org/linux-fsdevel/qk6hjuam54khlaikf2ssom6custxf5is2ekkaequf4hvode3ls@zgf7j5j4ubvw/t/#u Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@xxxxxxxxxxxxxxxxxx> --- fs/splice.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/splice.c b/fs/splice.c index 9d29664f23ee..81788bf7daa1 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1300,6 +1300,8 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out, } else if (opipe) { if (off_out) return -ESPIPE; + if (!((in->f_mode & FMODE_NOWAIT) || S_ISREG(in->f_inode->i_mode))) + return -EINVAL; if (off_in) { if (!(in->f_mode & FMODE_PREAD)) return -EINVAL; -- 2.39.2
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